Hello, you last heard from me when I won one of NIDA’s Science of Addiction Awards at the Intel Science and Engineering Fair. Since then, NIDA invited me to become an intern at its Intramural Research Program (IRP) lab in Baltimore, Maryland, and it was a memorable experience. I worked in the Molecular Targets and Medications Discovery Branch. The research I conducted at NIDA focused on cocaine addiction but also has applications for Parkinson’s disease and schizophrenia.
My project looked at how dopamine receptors in the brain might structurally combine to affect cocaine addiction and other neurological disorders. After taking two buses to come to the IRP campus every morning, I strapped on my gloves and started preparing the substance to give to the dopamine cells. My experiments usually lasted the whole day. I always waited with excitement at the end of the day to see the results. Through the experimentation, we developed a better understanding of the intracellular signaling of dopamine receptors (how they “talk” to each other), which could eventually help in developing new drugs to treat ailments associated with the dopamine receptors, including addiction.
I enjoyed the opportunity to work in a professional environment. I was able to contribute to the research in Dr. Sergi Ferre's lab, called the Central Nervous System Receptor-Receptor Interactions Unit. Every Thursday, our lab met to discuss our results. There, I had the amazing opportunity to work with my mentor, Dr. Xavier Guitart—something I will never forget. I was new to this specific field of neurology, so Dr. Guitart guided me through the whole process. He was always there when I needed guidance. It was so great to work in such a supportive environment.
Loss Led to Interest in Brain Science
I became interested in drug addiction because of my strong desire to contribute to research in the neurology field, after my uncle passed away from stroke in 2008. Stroke constricts blood flow to the brain, which is why it is a neurological disorder. Addiction is another disorder that affects the brain, which is what initially made me interested in drug addiction. My hope is that developing a treatment for addiction will also shed light on neurological disorders like stroke.
I've always wanted to be a medical doctor, possibly a surgeon. But now that I've had a glimpse of working in a research lab, it is something that I want to pursue later in life. Through this opportunity, I’ve learned that drug addiction is an important issue that affects many people, and that my efforts, along with many others’ efforts, will contribute to finding effective treatments. Working at the NIDA lab gave me a lot to think about as I enter my final year of high school.
Yamini Naidu is a senior at Valley Catholic High School in Beaverton, Oregon. Her lab work in NIDA's Intramural Research Program has inspired her to pursue a joint M.D.-Ph.D. program in neurology.
What do walnuts and our Word of the Day have in common?
Well, it’s a stretch, but fun to think about. If you crack open a walnut carefully, you can see it has two “sides”—just like the human brain. And that’s where our “word of the day” comes in.
The cerebral cortex covers most of the other brain parts inside your head—making up two-thirds of the brain’s mass. No surprise, since the cerebral cortex is what allows us to speak and understand, learn languages, play music, and a lot more.
Like a walnut, the cerebral cortex has two sides called “hemispheres.” The left hemisphere rules things like our ability to talk, write, and learn languages. The right hemisphere rules our musical abilities, and how we figure out distances and other “spatial” challenges. For example, does it look like you and all your friends can fit into that diner booth? Oops, not quite.
And that’s not all. Our sense of touch also uses both hemispheres of our brain! Walnuts anyone?
For more brainy words and others, check out NIDA’s glossary.
“This is drugs. This is your brain on drugs. Any questions?”
Sound familiar? For some of our readers, maybe not. This line actually dates back to the Partnership for a Drug-Free America’s 1987 classic television public service campaign. Perhaps even more memorable than the slogan was the imagery that accompanied it—a sizzling egg in a hot frying pan. Check out the video and see for yourself.
When it launched in the late 1980s, this classic public service campaign challenged the idea that drugs’ effects were temporary. The campaign message that drug addiction changes people’s brains and shatters people’s lives would soon start to take hold.
Brain Scans Replace Fried Eggs
Today, we don’t have to use a frying egg to demonstrate what a “brain on drugs” might look like. Through the use of brain-imaging technology, science can show us a real picture of how drug use affects the brain. By measuring the amount of glucose in a particular area of the brain, a brain scan (called positron emission tomography) can tell how active the brain is.
Take a look at the “control” scan on the left, which is the brain of a normal person. Look at all the red—this means that these regions of the brain are highly active since red represents glucose. The right scan is taken from someone who is on cocaine. What do you notice? A lot less red, right?, which means less activity. Reduced glucose can affect many brain functions, such as decision-making, memory, and concentration.
“This is your brain on drugs” just got a whole new meaning.
What drug-prevention slogans or images have the greatest impact on you? Send us a message or leave us a comment, and let us know what you think.
Have you ever wondered why you have to be 16 to get your driver’s license or 18 to vote or 21 to legally drink alcohol?
It’s partly because your brain is not ready to take on these responsibilities, since your brain is not fully developed when you’re a teen.
During the teen years, essential parts of the brain are still forming—like the prefrontal cortex, which allows people to weigh the pros and cons of situations instead of acting on impulse. This is one reason why teens are generally more likely to take risks than adults.
For example, with alcohol, teens may be less able to judge when to stop drinking. The Centers for Disease Control and Prevention (CDC) tells us that each year, more than 4,600 alcohol-related deaths occur among those less than 21 years old—that is way too many.
Research shows that alcohol and other drugs change the brain’s structure and how it works in the short and long term. In the short term, drugs affect your brain’s judgment and decision-making abilities, while long-term use causes brain changes that can set people up for addiction and other problems. The brains of people who become addicted get altered so that drugs are now their top priority—and they will compulsively seek and use drugs even though doing so brings devastating consequences for their lives and for those who care about them.
Do yourself a favor and use your brain to make smart choices, reach your goals, and achieve your full potential in life.
I remember my sophomore year in high school, feeling a life-changing moment of excitement when I read Dr. Karl Diesseroth’s work on optogenetics, a new field that involves studying the brain with light. I could never have imagined it would mark the beginning of a journey that would lead to presenting my research to NIDA Director Dr. Nora Volkow and her colleagues just 2 years later.
Along my journey, I was fortunate to have wonderful mentors from Yale University who truly cared about my interests. Professors Amy Arnsten and Ralph DiLeone are brilliant leaders in neuroscience research, yet they still found time to generously mentor. I performed optogenetics research in Dr. DiLeone’s laboratory, working closely with postdoctoral fellow Dr. Benjamin Land, who is a great, generous mentor.
Shedding Light on Connections Between Brain and Behavior
With optogenetics, light-sensitive chemicals (first discovered in algae) are inserted into the DNA of specific cells, giving us the ability to control those cells. In the project I worked on, we used this method to modify particular neurons in the prefrontal cortex of genetically altered mice. The prefrontal cortex is a region involved in regulating behavior and self-control.
We delivered blue laser light via fiber optics to the animals’ prefrontal cortex to control the timing of their behavior. This approach suggested a whole new way the brain could be repaired effectively, using light to target specific areas causing the trouble—instead of using medications that could affect the whole brain. By pairing genetics with light, optogenetics allows us to design new ways to repair the brain in people with brain disorders.
Undertaking such research felt especially compelling to me because of my desire to help people with difficulties stemming from disorders affecting their prefrontal cortex. Millions of individuals suffer from such disorders, which include drug addictions, schizophrenia, depression, Alzheimer’s disease, and Parkinson’s disease. These conditions might be better managed or even cured in the future with new treatments growing out of optogenetic research.
Sharing My Research and My Passion
As a result of these experiences, I’ve presented my research many times to different audiences. I have talked to students from elementary through high school, participated in Connecticut state science competitions, presented at a regional competition at the Massachusetts Institute of Technology and then at the George Washington University as a national finalist in the Siemens Competition in Math, Science, and Engineering, at the American Academy of Neurology, and finally at the Intel International Science and Engineering Fair, where I received the NIDA Addiction Science Fair Award. Presenting to Dr. Volkow and her colleagues proved to be one of the greatest opportunities. I loved responding to their rapid-fire questions after giving my presentation. I also had the chance to tour the National Institutes of Health campus and Intramural Research Program laboratories.
Winning this award offered me a window to seeing the best translational research in action—applying what we learn from basic research to develop treatments and then try them out in clinical trials. It seems there are no limits to the questions that could be imagined and tested and the scientific inquiry that could be accomplished on the road ahead.
John Solder is currently a freshman at Yale University. The optogenetics project he worked on is part of a manuscript he co-authored, to be published in the Proceedings of the National Academy of Sciences (PNAS). He will be continuing research in this area.
You probably know that your genes help make you who you are. Except for identical twins, everyone has a slightly different set of genes, and when our genes interact with our environment, that’s what makes us unique individuals.
Genes give us different hair, eye, and skin colors, and affect our height and weight. Genes also affect the inside of our bodies, and influence how organs like the heart, lungs, and even the brain work. But did you know that genes also affect how you behave. And the opposite is true as well–how you behave can affect your genes!
Scientists have learned that genes are affected by our lifestyles–what we eat and drink, how much we exercise, how much we sleep. These factors influence how genes are expressed–or turned “on” or “off”–in our bodies. That can have pretty major effects on health.
Currently, scientists are studying how taking cocaine affects your genes. Scientists have known for a while that using cocaine over a drawn-out period can lead to permanent changes in the brain. Teen brains may be especially vulnerable, because they are not yet fully developed. But what causes those changes to happen?
In May 2009, a NIDA-funded study found one piece of the puzzle-and it has to do with, yep, genes. For the first time, scientists have discovered that mice given repeated cocaine exposure “turn on” genes in certain regions of the brain. These genes, called sirtuins [pronounced sir-2-ins], are activated by long-term exposure to cocaine, and it looks like they contribute to the development of addiction.
When the scientists prevented sirtuin activation in the brains of lab mice, the mice didn’t find cocaine to be as good, or rewarding. To say it another way, without turning these genes “on,” cocaine couldn’t give the mice a “high” anymore, and the mice didn’t want the drug as much.
These results are pretty exciting, because if scientists could develop a treatment based on these genes, it might help people suffering from cocaine addiction. That kind of treatment is a long way off–but at least now the scientists know how cocaine affects genes, and how that affects the brain. And that’s a good start.
To find out more about how cocaine affects the body, visit NIDA’s website, or read this basic overview of how genes and drug addiction interact.
Can you put yourself in someone else’s shoes? Developing empathy—being able to read someone else’s feelings and relate them to your own—depends to some extent on brain development.
Although it sounds simple to be able to imagine the nervousness your friend felt about playing her first JV soccer match, for example, it may be hard for teens to have empathy because their brains aren’t yet hard-wired for it. Brain imaging studies show that teens and adults may use different mental strategies for figuring out someone’s intentions or motives for doing something. The ability to understand what others are feeling is important in forming close relationships, tolerating differing points of view, and keeping us from hurting others because of misunderstandings.
Even more, some people seem to be inherently better at empathizing than others. Dr. Abigail Marsh, a researcher at Georgetown University, studies empathy—or the lack of it—in teens. Dr. Marsh measures this quality by using brain imaging technology to look at activity in the brain’s amygdala while showing both groups of teens pictures of fearful faces. She theorizes that “exposure to and correct interpretation of certain distress cues may predict the likelihood” of developing behaviors like empathy.
According to Dr. Marsh, you can aid the development of empathy by practicing the following three ways of tuning into others’ feelings:
- Put yourself in someone else’s shoes. Is it possible that it hurt your friend’s feelings when you said her choice of birthday presents “sucked”? Can you share in your sister’s excitement for acing her physics exam?
- Recognize others’ emotions if you have felt them yourself. How do you feel when someone makes you mad? Have you ever noticed when something you said out of anger or frustration had that effect on someone else?
- Pay attention. Are you too busy tuning into how no one “gets you” to notice the needs of other people around you? Other people may need your understanding as much as you need theirs.
Imagine this: You're playing basketball; it's the last quarter. In fact, you only have 30 seconds to make the winning shot. You shoot, it soars through the air, you hear the buzzer go off...and then you see the swoosh.
You just won the game for your team. How do you feel?
The answer to that question involves a chemical in your brain, called dopamine—our word of the day. Dopamine delivers important messages between neurons (brain cells). That's why it's called a "neurotransmitter." Dopamine is an especially important neurotransmitter, because it helps to control movement, motivation, emotions, and sensations like pleasure.
Back to the basketball game. After you made that winning basket, dopamine sent "messages" to your neurons to help you feel happy, pumped, and overjoyed that you made that winning shot. Dopamine would also be working away in your teammates' brains as they ran out onto the court to celebrate, and in the brains of the cheering fans jumping up and down in the stands.
But it doesn't stop there. Dopamine is at work all the time, delivering messages to neurons and motivating you to participate in the more basic activities of life, like eating foods you like or spending time with family and friends. How dopamine works in the brain is especially important in teens since teens' brains are still developing. When dopamine levels are affected by drugs like cocaine, it can affect the brain's "wiring," causing important messages to get lost in translation. Messing with dopamine can affect your motivation to go to prom or ability to make that winning basketball shot,—even your ability to feel happiness. And that's why drugs might cost you more than just the basketball game.
For more in-depth resources and other brainy words, check out NIDA's interactive glossary that fuels my "Words of the Day."
What’s that purple goo coming out of that big slug’s rear end?
Oww! That crayfish pinched me again!
Do I REALLY have to pick up that cockroach with my hands?
This is what I have to listen to in my lab at the beginning of each school year when high school seniors are conducting research on neuroscience. A public high school may seem like an unusual place for neuroscience research, but the teens I teach are really into it. Let me tell you how we got started.
More than 10 years ago, a major shift at our school saw many freshmen and sophomores registering for AP Biology instead of waiting for their junior or senior years. It occurred to me that after taking AP Biology, some students may wish to explore neurobiology in greater depth, so I created a class called Recent Advances in Neurobiology.
It’s pretty much like a graduate school seminar class: students do about 45 pages of reading homework on various topics in neurobiology, then come in and discuss everything they’ve read. Half their grade is based on class participation (i.e., talking, which high schoolers seem to be fond of anyway). Of course, they are “inspired” to come to class prepared because there is a quiz every day. (Yay!)
The topics for reading and discussion are chosen by the students, and throughout the semester we usually cover the neurobiology of Alzheimer’s disease, cocaine, synesthesia, marijuana, gender, and stuff like that. The students seem to love the material and the format.
Three years ago we decided to take this neuro stuff a bit further: we created a new Neuroscience Research Laboratory where seniors can work on year-long research projects.
I have students studying the nervous system of the sea slug Aplysia, the escape response in Madagascar hissing cockroaches, and the neurobiology of behavior in crayfish. Other students aredesigning a wheelchair (and other peripherals) to be controlled by brainwaves. This program can be established at almost any high school. All you need is a strong desire and commitment – and a sign that says “We ? Brains,” of course.
Oh, yes. By the end of the first week they know what the purple goo is and they’re picking up the cockroaches. But somehow they still get pinched by the crayfish.
Paul A. Cammer, Ph.D., Director Neuroscience Research Laboratory Thomas Jefferson High School for Science and Technology
More people understand now the harmful effects that smoking has on the body as well as the addictive effects of nicotine. The good news is that teens seem to be getting the message—SBB recently reported that smoking rates among 8th-, 10th-, and 12th-graders are at an all-time low.
But many teens are still smoking—according to the 2011 Monitoring the Future Study PDF [230 KB], 19 percent of high school seniors reported smoking in the past month.
New NIDA research gives yet another reason for teens to avoid lighting that first cigarette—nicotine may “prime” the brain to enhance cocaine’s effects, making it a very dangerous “gateway drug.” That means it could open the door to other drug use.
Science Suggests that Nicotine Changes the Brain
Evidence shows that most people who tried drugs like cocaine were first tobacco or alcohol users. This concept of “gateway drugs” has been controversial, mostly because people question whether prior use of drugs like nicotine, alcohol, or marijuana actually leads to later drug use. Before now, studies have not been able to show a biological reason why smoking or other nicotine use could increase a person’s chances of using illegal street drugs.
That changed when NIDA researchers found that mice exposed to nicotine in their drinking water for at least 7 days showed an increased response to cocaine. Why did this happen? Researchers recognized that nicotine actually changes the structure of your DNA, it reprograms how certain genes are expressed—in particular a gene that has been related to addiction—and ultimately, it enhances the response to cocaine.
Why did this happen? Researchers recognized that nicotine actually changes the structure of your DNA, it reprograms how certain genes are expressed—in particular a gene that has been related to addiction—and ultimately, it enhances the response to cocaine.
Moving on from mice, researchers looked at statistics in humans—in particular at when people began nicotine use and their degree of cocaine dependence: Among cocaine users who smoked cigarettes before starting cocaine, the rate of cocaine dependence was higher compared with those who tried cocaine first (before smoking cigarettes).
The study doesn’t mean that every person who smokes cigarettes will eventually become addicted to cocaine. But it does suggest that if a person who smokes cigarettes tries cocaine, their brains may have been changed by nicotine to make it more likely that they will become addicted to cocaine.
Need help quitting smoking? Take a look at these resources from the Centers for Disease Control and Prevention.
There’s no better time than the upcoming Brain Awareness Week, from March 11‒17, to learn more about the most fascinating organ in your body.
The included image from the Society for Neuroscience, a partner of the Dana Foundation for Brain Awareness Week, shows some of the most critical parts of your brain.
Here’s what each part is primarily responsible for—and guess what? As the image shows, these are also the brain regions most affected by drugs of abuse:
Prefrontal cortex: This part is often referred to as the “CEO of the brain.” The prefrontal cortex is responsible for critical thinking and abstract thought, as well as many other functions like focusing attention, organizing thoughts, controlling impulses, and forming strategies for future action. The prefrontal cortex is one of the last regions of the brain to mature, so changes caused by drug abuse could have long-lasting effects.
Nucleus accumbens: Part of the so-called “pleasure center,” the nucleus accumbens is thought to play an important role in reward, pleasure, laughter, aggression, and fear.
Amygdala: Research shows that the amygdala has a major role in processing memory and emotional reactions, such as fear. The amygdala is part of the limbic system.
Hippocampus: Also part of the limbic system, the hippocampus plays important roles in moving information from short-term memory to long-term memory.
Ventral tegmental area: This structure is important in thinking, motivation, and intense emotions relating to love.
Scientists are constantly studying the brain and learning more and more about how different brain structures relate to addiction. We know drugs change the brain, but the effects of these changes are not yet fully understood.
Protect your brain. Make the healthy choice to stay away from drugs and alcohol.
What questions do you have about the brain? Let us know in comments. And Happy Brain Awareness Week!
Our word for today is: Cerebellum
Cerebellum: A portion of the brain that helps regulate posture, balance, and coordination during activities such as playing ball, picking up objects, and balancing.
Why do I like this word so much? Say it again: "cer·e·bel·lum" (s?r'?-b?l'?m)—yup, it's my namesake! When we walk down the street or concentrate on keeping our balance, our cerebellum is guiding us. The cerebellum coordinates our voluntary muscle movement as well as our posture and balance, like a puppeteer helping us put one leg in front of the other. Suppose you're playing ball? Picking up your pet? Playing a musical instrument? Your cerebellum is hard at work inside your head so you can slam dunk that basketball, hold onto the cat, and play each note on your electric guitar perfectly. And these are just a few of the activities that the cerebellum handles for us. The cerebellum is located just above the brainstem, where our brain connects to our spinal cord. The average teen's cerebellum weighs about 6 ounces. That's about one-eighth of the total weight of our brain, which weighs about 3 pounds. Hmm...who knew something so little could be so powerful? You can look up more words in the NIDA for Teens glossary.
That was my question. Why do people do the things they do. I used to just love to sit and watch people. I could sit at the park or in the mall for hours and just “people watch.” I think that's why when I got to college I eventually became a psychology major. I wanted to understand more about why people behave in certain ways and what makes people choose to do different things.
One thing fascinated me in particular was why do some people smoke? My parents smoked when I was growing up. I remember my dad decided to quit and he seemed to do it so easily but when my mom tried, it was so hard for her. She seemed to try everything to quit, and then her mood would get so bad that soon she was buying another pack. Eventually though she did quit...I don't know what finally did it—back then we didn't have the patch or gum and there were no medications. No one talked about smoking being an addiction, it was just a habit, and people thought you only needed willpower to be able to quit. Imagine how hard it must have been for my mom to see my dad being able to quit so easily and her having to struggle so hard.
Smoking affects people very differently. When I was about 18, I had some very cool friends who smoked and so I wanted to smoke too. So I tried it but, lucky for me, I hated it. That was my first lesson in genetics. My second was when I took a class in behavioral genetics, and suddenly all my life experiences started to click, to make sense. My mother struggled to quit because she had a genetic tendency for addiction, not just smoking but also for alcohol, which eventually took her life. I was lucky I had many of my dad’s protective genes so substances of abuse were never tempting to me.
It was these life experiences that drew me to the field of genetics, to better understand why some people struggle so mightily with addiction like my mother. We don't have all the answers even today, but many scientists are working on this puzzle to help find better treatments so people can overcome their addictions and reclaim their lives. Think about becoming a scientist to help solve this puzzle and make life better for so many! It’s a great field and very rewarding, too.
Dr. Miner is the Deputy Director of the Office of Science Policy and Communications (OSPC) at NIDA. She helps coordinate all of NIDA’s communications to Congress, constituent groups, and the media. She also oversees NIDA’s plans for the research it will support. Cindy earned her Ph.D. in psychology from the University of Colorado in 1986. She’s published numerous papers and book chapters on the genetic and biochemical bases of addiction. Oh—she’s also a wonderful person, an Emmy award winner (as part of NIDA’s work on the HBO special, “Addiction”), and a super athlete! So being a successful “science nerd” is just one of her many talents
* Dr. Miner will soon leave her position at NIDA to start an exciting new job with the Food and Drug Administration’s new Center for Tobacco Products, helping to start up their Communications and Policy offices. SBB wishes her the best!
- Most areas of the brain stop producing new neurons (the cells that transmit information from the brain to different parts of the body) after we’re born, but the hippocampus, a structure crucial to learning and memory, continues to form new neurons throughout life.
Recent NIDA-funded research suggests that drugs may reduce production of those hippocampal neurons, which may increase the risk of drug addiction.
- Compared to most people, those who are addicted to drugs and alcohol are more likely to go for instant gratification over long-term rewards. People who are dependent on drugs have trouble remembering the positive and negative consequences of their choices.
A NIDA study found that doing exercises to improve memory helped participants wait for a larger sum of money rather than accept a smaller one right away. This means that memory training may have a place in substance abuse treatment as a way to help patients reject quick drug highs in favor of the longer term satisfaction of a drug-free life.While NIDA scientists are focused on reducing drug addiction and its consequences, their work provides knowledge of brain science that can be applied in other areas of health. Interested in learning more about the brain? Visit the Brain Awareness Week Web site or “Like” the campaign on Facebook.
Is your brain an organic computer? Your brain does a lot of things a computer does, like math, logic, analyzing input, creating output, and storing and retrieving information. Even at the cellular level, there are some striking similarities between brains and computers. Our brain has billions of neurons that convey and analyze electrical information. This information is binary, meaning a neuron either fires a burst of electricity or it does not fire at all. Likewise, computers transmit information electrically. And at the most basic level, computers work using bits of information that are also binary, where each bit of information is either a “1” or a “0,” nothing in between.
But brains do a lot of things that computers cannot. Our brains feel emotions, worry about the future, enjoy music and a good joke, taste the flavor of an apple, are self-aware, and fall in and out of love. Albert Einstein’s famous equation E=MC2 was not the result of a computer algorithm but, rather, of a brain making a great intellectual leap. If a brain is merely an organic computer, how can it do these things?
Part of the answer may be that whereas neurons process information like a computer, they are not the only type of brain cells processing information. Neurons only make up a small portion of your brain cells—about 15 percent.
Enter the All-Important Glia Cells
The vast majority of brain cells are called “glia” cells. For over 100 hundred years, most brain scientists saw glia as being relatively unimportant. Their function was believed to be mostly cleaning up “molecular trash” created by neurons. However, research is now showing that glia do much more than housecleaning. They are involved in learning and memory, and they help repair damaged brain areas. Glia can also communicate with neurons and with each other through “gap junctions” across large areas of the brain.
To illustrate how important glia are, almost every disease of the brain is partly or solely the result of glia malfunction. Scientists are now discovering that glia may also play a pivotal role in drug abuse, where changing glia activity may reduce drug abuse and addiction.
David Thomas is a NIDA scientist and Program Officer. He received a Ph.D. in Experimental Psychology from American University in Washington, DC, and has conducted research in analgesia (pain relief) and itch. He currently works at NIDA promoting research to find better pain medications that are not addictive
Is there something magical about drugs and alcohol with us humans? So what's our fascination and why do some of us like them so much?! Actually, before we try and answer that one, let me just say: we are not alone. Some of the drugs we use, abuse, and become addicted to today were actually "discovered" by animals first.
For example, you know why we have coffee today? Well, the "legend of the dancing goats" says that coffee beans were first discovered in a field in Ethiopia by a goat herder who noticed that his goats were acting weird sometimes, running around and dancing wildly. He couldn't figure out why and so decided to study them. He saw them eating small red berries on a certain shrub found in the area—turns out they were coffee plants. After eating the berries with the coffee beans inside, the goats started their "dancing." Legend also has it that the goat herder also started eating the berries and dancing with them!
Plenty of similar stories and observations have been made of other animals that seem to get "high" from naturally occurring drugs or fermented fruits. Cats are attracted to the valerian plant and to catnip, which seems to give them extreme pleasure. In parts of Africa, the marula fruit ripens, and animals—from monkeys to elephants—are attracted to the overripe and fermenting fruits that make them act "funny." Birds have been seen sitting on smoking tree trunks after bush fires and seem to be intoxicated—they get dizzy and fall off of the smoldering trunk only to get up and do it over and over.
Back to our question…so why do we (or at least some of us) and our animal counterparts like these natural-occurring substances and synthetic or man-made drugs? The answer is simple…blame it on our brains! We have evolved a brain that allows us to see, hear, taste, move, think, etc., and also to repeat things that feel good. That happens because a part of our brain sends out feel-good signals when we do something we enjoy, like eating good food, playing a video game, kicking a goal in soccer, listening to our favorite music, or going upside-down on a roller coaster. The system that says to us: "hey, that was good, do it again!" is called the "reward system".
Turns out that alcohol and drugs affect this system really well; they are effective at going right to our brain's "reward system" and putting it into high gear. This very effective stimulation of the reward system is why many people can become addicted to drugs, since feeling good is what drives much of our behavior. Drugs, in a sense, trick the system that has evolved for helping us in our world and instead can turn our world upside down.
As a scientist and Division Director at NIDA, I am committed to learning more about how drugs exert their effects in the brain so that we can come up with better ways to prevent young people from getting "tricked" by drugs and sliding into addiction without even realizing it.
As Director of NIDA's Division of Clinical Neuroscience and Behavioral Research, Dr. Joe Frascella heads up a program that supports studies in humans to advance our understanding of brain and behavior in drug abuse and addiction. Studies are mainly on neuroscience, adolescent development, and treatment, with a goal of translating research results into real-world use.
NIDA’s Glossary defines the limbic system as “a set of brain structures that generates our feelings, emotions, and motivations. It is also important in learning and memory.”
The limbic system, known informally as the “center for emotions,” is made up of five parts that help ensure our survival, including the ability to feel emotion, long-term memory storage, memory retrieval, and other behaviors directly connected with the emotions.
Each part has a separate role that makes the system run smoothly.
1) Amygdala—a tiny, almond-shaped structure commonly associated with processing emotions like anger, fear, and pleasure.
2) Cingulate Gyrus—a structure that receives messages from other parts of the brain and is essential in higher thinking functions, respiratory control, and memory, and learning.
3) Fornix—a tough, arch-shaped band that connects the two lobes of the cerebrum (the large rounded structure that makes up most of the brain and is divided into two hemispheres).
4) Hippocampus—a brain structure that is key to memory storage and retrieval; damage to it often means significant long-term memory loss.
5) Hypothalamus—a brain structure that regulates involuntary or automatic responses, including body temperature and food digestion. Drugs disrupt the feelings and motivations that form the basis of normal behavior. A person abusing drugs is artificially feeling pleasure by interfering with the limbic system.
The human brain continues to grow during the teen years, well into the twenties. It’s a scientific fact that abusing drugs and alcohol while your brain is still developing can change the brain’s structure and how it works—both in the short and long term.
Yale University scientists recently explored how some of these changes occur when the brain is exposed to the stimulant cocaine—and learned that some changes result from the brain trying to protect itself.
Your Brain’s Self-Defense
When exposed to cocaine for the first time, the teen brain tries to defend itself against the harmful drug by changing the shape of the brain cells (or neurons) and synapses. This defensive reaction is controlled by a certain pathway in the brain involving integrin beta1, a crucial gene in the development of the nervous system in humans and most animals. The scientists discovered that if they blocked the pathway—and prevented this cell-shape change—the mice became three times more sensitive to the effects of cocaine.
This research may explain why some people who use cocaine end up addicted to the drug while others escape its worst effects. Everyone’s genetic makeup is unique. It’s possible that those with strong integrin beta1 pathways are better able to avoid the dangerous effects of the drug. More research is needed to discover which genes can protect the brain from the effects of cocaine and other drugs.
Good News: Cocaine Use Is Down
What’s your new geometry teacher’s name? How do you get to your friend’s house? Where did you put your smartphone? Have you noticed that practice makes you play the piano better?
Every day, we learn and remember things that we experience in our lives. If we didn’t, we would get lost, not be able to sing along to our favorite song, and not pass that important midterm exam.
But how do we learn new things? And how does the brain store the memories so that we can recall them at a later time?
By studying the process of learning and memory, neuroscientists hope to be able to find treatments for those who lose their memories because of aging or diseases like Alzheimer’s. We may also be able to help those who suffer anxiety and depression that are triggered by bad memories from traumas like childhood abuse, car accidents, or war. We might also help people in drug abuse recovery stay off drugs by extinguishing memories that stimulate their desire to seek and take more drugs.
A Look at the Hippocampus
Neuroscientists are learning more about the process of learning and memory by studying the hippocampus, a brain region involved in forming and retaining memories. Neuroscientists don’t know exactly how learning and memory occur in the brain, but whenever learning occurs, neurons in the hippocampus become active. Learning is thought to be due to an increase in the activity between many neurons that communicate with each other.
How do neurons communicate? When a nerve impulse reaches a neuron, the neuron is activated and releases a chemical, called a neurotransmitter, at the synapse, or the place where two neurons connect. The neurotransmitter crosses the synapse, where it connects to a receptor molecule located on the adjacent neuron. This binding of the neurotransmitter activates the second neuron, which sends a neurotransmitter to the next neuron, and so on. This process continues from neuron to neuron as the nerve impulse travels throughout the brain.
Neuroscientists have discovered that when you are not learning, a nerve impulse will cause a neuron to have a low level of activity, but that during learning, the electrical activity between two neurons will be increased. This phenomenon is called long-term potentiation or LTP, and researchers have found that animals do not learn when LTP is blocked.
One of the goals for neuroscience research is to be able to manipulate LTP and, as a result, also influence learning and memory formation. Someday neuroscientists hope to be able to help your grandmother find her glasses and purse, to reduce the stress and anxiety that is felt by those who have memories of traumatic events, and even to extinguish the memories that cause a person to want to continue to use drugs.
Roger Sorensen, Ph.D., M.P.A., is a NIDA program official who directs a grant program that supports basic science research on the physiological effects of drugs of abuse on the brain and nervous system. He was trained in neurochemistry and expects that someday scientists will be able to determine how this complex organ known as the brain makes us think, feel, and be who we are.
Here at NIDA, we can't learn enough about the brain. Other scientists are brain-obsessed too-there's even a Brain Awareness Week, a global campaign to spread the word about the progress and benefits of brain research. This week, people all over the world will take some time to learn about the complex and beautiful brain. So, in the spirit of the week, here's some "brain bits."
Everyone knows that your brain helps you learn-it stores information and helps you put different pieces together to draw conclusions about all sorts of things: from math problems to history essay questions to whether you like the taste of tomatoes.
The brain relies on a bunch of chemicals called neurotransmitters to get messages from one part of the brain to the other. It's pretty amazing how each neurotransmitter attaches to its own kind of receptor-like how a key fits into a lock. Messages zip through the brain on the right routes thanks to this intricate process.
But drugs can really mess up the brain's traffic patterns. The chemical structure of some drugs, like marijuana, imitates the structure of a natural neurotransmitter. In this way, drugs can "fool" receptors, lock onto them, and alter the activity of nerve cells.
The problem is, drugs don't work exactly the same way as the natural neurotransmitters they resemble. So a brain on drugs sends messages down wrong pathways throughout the brain. Marijuana, for example, can alter concentration and memory. Other drugs can literally reset what the brain needs to feel pleasure so that, without the drug, a person dependent on it feels hopeless and sad.
As you can see, the brain is a complex organ, worthy of its own week of honor. Learn more about your brain and the harmful effects of drugs from these resources:
Ruben Baler, Ph.D., is not your typical neuroscientist. Baler has studied in his native country Argentina, the U.S., and Israel. He is fluent in three languages. His work at NIDA enables him to publish scientific papers and collaborate on presentations and speeches with NIDA’s Director, Nora D. Volkow, M.D. His true passion is teaching young people about the brain. He talks to college students at George Washington University in Washington, DC, and regularly interacts with high school students in and around the Washington, DC, area. Dr. Baler talks in this podcast about the teen brain—how it develops fast, just like teens themselves. And how, sometimes, that growth keeps young people from using their best judgment when it comes to risky behaviors, such as experimenting with drugs and alcohol, driving too fast, or jumping headlong into relationships.
Dr. Baler: Hello, my name is Ruben Baler. I am [a scientist] with the National Institute on Drug Abuse, NIDA. It’s probably helpful to think of the brain as a computer, which in essence, it is. It’s a very complex computer. It’s made up of circuits that affect or mediate all sorts of different functions in the brain. You can think of the learning circuit, the memory circuit, the higher thinking (cognitive function) circuit. There are all sorts of networks in the brain that interact with each other and with the environment. They are the substrates (or key brain areas) where drugs of abuse have their effects. The main substrate in the brain that is impacted by drugs of abuse is called the circuit of reward. It is the area deep inside the brain that influences feelings of reward, feelings of pleasure. Drugs of abuse hijack the normal pathways of reward and lead the brain to think that the drug-induced experience is the highest possible goal from now on.
SBB: What makes the teenage brain so special?
Dr. Baler: One of the main reasons is that different parts of the brain develop at different rates. There are two main parts: one area, called the amygdala, governs our instincts, our gut feelings. That area develops early on and is already mature in a teenager. Then there is another area called the prefrontal cortex, a part of the brain that takes much longer to develop, to fully mature. The teen brain is different because the ability to make good decisions really depends on the balance between these two structures: the prefrontal cortex and the amygdala, part of the limbic system that develops so early on.
So we can say that teenagers make decisions mostly based on this instinctual part of the brain, these gut feelings, because the prefrontal cortex has not yet reached [developed] the ability to fully exert control and keep tabs on the already-mature limbic system.
SBB: Do you think that by studying the brain and knowing how it’s linked to addiction and other high-risk behaviors, teens can learn to “tame” their brains?
Dr. Baler: Well, one school of thought says that by providing fact-based information to teenagers—like the fact that their brains are still developing and they may make decisions differently than adults—may urge them to stop and think, and make better decisions as a result.
There are big, big questions in neuroscience. For example: where is consciousness? Where does consciousness lie? We’d like to understand how this computer (the brain) leads to things like music, creativity, poetry—very complex products of this very complex machine.
*Note: In order to hear the podcast you will need to have a media player on your computer.
SBB has talked a lot about how drug addiction is a complicated brain disease. But it’s not the only one. Obesity also involves the brain and is the subject of an HBO special that takes a serious look at this complex problem. The 4-hour documentary series “The Weight of the Nation” covered everything from fatty liver disease in overweight children to how humans are wired to find pleasure in food to how our food supply has changed over the years. If you missed it in mid-May, you can go to HBO’s Web site and see it for free. To get a better idea of the obesity problem, check out this creative infographic, “Obesity: Complex But Conquerable,” from the Institute of Medicine. Our Brains: Wired To Find Pleasure in Food You may see overweight people and wonder, “Why don’t they just stop eating so much?” If the solution were that simple, then nearly two-thirds of the U.S. population would not be either overweight or obese. NIDA Director Nora D. Volkow, M.D., spoke in the HBO series about how brain science relates to obesity. She noted how early in human civilization, when a person’s survival depended on the ability to hunt and gather, our brains associated tasty food, like bananas, with pleasure, making it more likely that a person would climb a tree to get the fruit. Today, that powerful connection still exists between food and pleasure, except now we don’t have to work so hard for our food. For some people, the rush of dopamine associated with eating a food they like may cause them to overeat impulsively—a brain reaction they cannot control, according to Dr. Volkow. It is a similar response to what happens in drug addiction when people compulsively seek and use drugs despite the negative consequences. Nature AND Nurture The documentary emphasized that our society—with its overabundance of fast food restaurants, massive portion sizes, and schools serving foods like French fries and pizza—makes it easy for people to make poor food choices. To reverse this bad health trend, we need to change our environment and make better choices. Our stomachs, livers, and hearts aren’t the only organs affected by obesity—the brain also takes a hit. Dr. Volkow said, “Obesity negatively affects the function of the brain. The greater the problem of obesity, the less activity in areas of the brain that are extremely important for cognitive (thinking) operations.” Find out more about what other experts from the National Institutes of Health had to say about obesity, and preview a clip from the documentary:
When our brains are healthy, we barely notice this marvel of engineering that controls our every thought, feeling, and move. But the many people suffering from brain disorders, including addiction, know that malfunctions in the brain can change who we are and how we manage our lives.
For a closer look into how our brains function—or malfunction—scientists have discovered a new way to turn individual neurons and cell circuits on and off using light.
Neurons in the brain pass electrical impulses back and forth thousands of times a minute, but turning them on and off isn’t quite as simple as flipping a light switch. First, researchers have to insert light-sensitive genes, taken from algae, into specific neurons. Then, using lasers connected to thin fiber optic threads, they can activate or deactivate the modified cells to see how neurons or groups of neurons work together. So far, this new field of optogenetics research is limited to animal studies.
Working To Understand Brain Disorders
Scientists have successfully switched mouse neurons on and off to see how different brain circuits control habits, emotions, and behaviors. The technique may also help scientists understand the causes and potential treatment of specific brain disorders such as schizophrenia.
Optogenetics is also helping scientists understand how addiction affects the brain.
Researchers at the Massachusetts Institute of Technology trained mice to run through a maze for a chocolate reward. Out of habit, the mice continued to run through the maze even after the reward was no longer present. But by using optogenetics to activate cells of a brain area called the basal ganglia, the researchers turned off the chocolate-chasing habit. (The basal ganglia contain the brain’s reward circuits, which are involved in addictions.)
Scientists are hopeful that optogenetics could eventually help treat addiction and other neurological conditions in people.
Watch this video to learn more about optogenetics:
Euphoria: A feeling of well-being or elation.
Euphoria is that excitement you get from getting a perfect score on a test, or attention from someone you have a crush on. It can come from a roller coaster ride or as the rush from a physical activity like downhill skiing, especially the first time. These feelings of euphoria are all healthy and natural.
What's not healthy or natural is taking drugs to feel "euphoric." Drugs of abuse artificially produce euphoria by manipulating your brain chemistry to make it seem that something exciting is happening. To get this feeling again, you may choose to use the drugs again-and again. And that can lead to craving and addiction.
Over time, the brain needs more of the drug to get the same feelings of pleasure. Why? The drug causes surges, like waves, of the brain chemical dopamine, which initially produce the euphoria. After repeated hits, though, the brain adjusts to this higher level of dopamine by making less of it and by reducing the number of receptors that can receive and transmit the signals it sends. Pretty soon, the drug abuser is taking the drug just to bring the dopamine functions back up to normal and to avoid the horrible craving that compels them to seek and use drugs even when their lives and health are falling apart. That is really the essence of addiction.
But the good news is that natural, healthy experiences of euphoria don't wreck the brain's chemistry. So think about what you do in life that makes you feel good. Spending time with friends, playing with your dog, doing sports, seeing a good movie? Any of these activities can create a natural euphoria by triggering the brain's reward system the way it was meant to work.
So don't let drugs fool your brain, and then wreck it.
Dr. Nora Volkow, Director of NIDA, is an avid runner—6 miles a day!
We all know the benefits of physical activity on the body, but as a neuroscientist, Dr. Volkow is also interested in how exercise helps the brain.
Working your body can definitely make you feel good—but can you really get a “high” without drugs?
Doing exercise like running actually stimulates the brain's reward system and releases the same feel-good brain chemicals that drugs do. The best part of “getting high” through exercise is that you avoid the negative health effects of drugs, while also making your body stronger.
What causes this natural high? Here are a couple theories from research:
Theory 1: Endorphins and Dopamine
The body produces its own kind of opioids—chemicals closely related to the drugs morphine or heroin—called endorphins. Endorphins are produced when we feel excitement or love, or when we eat tasty food. The brain also produces endorphins during intense workouts.
The release of endorphins stimulates the brain's reward system to release dopamine—the brain’s #1 feel-good chemical. Increased dopamine in the brain causes the euphoria people get from drugs and may explain the runner’s high too.
Theory 2: Endocannabinoids
Other research suggests that a different class of chemicals, called cannabinoids, are also released by exercise and may contribute to the runner’s high.
Your body actually makes cannabinoids—called endocannabinoids—that act on the same brain receptors as the THC in marijuana. It’s no surprise then that cannabinoids are associated with the pleasant sensation, reduced anxiety, and pain reduction that marijuana can bring.
The runner’s high might even help people who are addicted to drugs. NIDA is supporting research to find out how exercise and the release of those feel-good brain chemicals might help prevent substance abuse, or even encourage people who do drugs to replace one habit with another—in a good way.
So, does knowing that exercise can make you feel happy make you want to pop in your earbuds and take a run??
I'm sure you've heard that abusing alcohol hurts your health. But how many years of drinking do you think it takes to visibly affect your brain? Ten years? Twenty?
It turns out that it doesn't take that long at all—in fact, scientists can already see changes in the brains of teenagers who drink.
In a new research study, Professor Susan Tapert of the University of California at San Diego used an imaging machine called an MRI to scan the brains of teens who binge drink—defined as drinking 4 or 5 (or more) drinks in a couple of hours. Dr. Tapert found that the "white matter" in their brains—the part that transmits signals, like a television cable or a computer USB cord—was abnormal when compared with the white matter of teens who don't binge drink. Transmitting signals is a big part of what the brain does, so affecting the white matter in this way could also affect thinking, learning, and memory.
The really scary part is that these teens weren't alcoholics, and they didn't drink every day. All they did (to be considered "binge drinkers") was drink at least four (for women) or five (for men) drinks in one sitting, at least one time during the previous three months.
How could it be possible for just a few sessions of heavy drinking to affect the white matter of the brain? Well, science has shown that alcohol can poison brain cells and can alter the brain's white matter in adult alcoholics. Dr. Tapert thinks that teenagers' brains are even more susceptible this way. She says, "because the brain is still developing during adolescence, there has been concern that it may be more vulnerable to high doses of alcohol."
Many questions still remain, including how long it takes before these changes occur, and how much they affect the function of the brain. To figure this out, scientists would have to look at the binge drinkers' brains before and after they started drinking. That way, they can tell if the differences might have already been there before the teens started drinking. It's possible that having abnormal white matter in the brain somehow increases the chance of being a binge drinker. In order to answer that question, Dr. Tapert says they need to do longer studies that follow teens' brain growth over time.
The bottom line? If you're a teen, drinking to the point of getting drunk could damage the white matter of your brain—even if you do it only once in a while.
Find out more through the following resources:
- SAMHSA Fact Sheet on Binge Drinking
- NIH Fact Sheet on Underage Drinking (PDF, 305 KB)
- USCD News Release: Binge Drinking May Hamper Information Relay System in Teen Brain
- Dr. Tapert's Study: Altered White Matter Integrity in Adolescent Binge Drinkers
- NIAAA's Rethinking Drinking Web page
Do you or your friends play video games? Many video games create a virtual reality, a world that only exists on a computer, made up of vivid images and engrossing stories. Researchers are looking at ways to use the power of virtual reality to help people with conditions ranging from fear of flying to drug addiction. The use of virtual reality to help people with specific health conditions is called virtual reality therapy.
Researchers at Duke University are trying virtual reality therapy as a treatment for drug addiction. This NIDA-funded research may help people recovering from addiction keep from returning to drug use (relapse). This is how it works:
- Researchers use virtual realities to create common situations where people recovering from drug addiction might encounter drugs.
- These virtual situations help people develop strategies to overcome cravings they might feel in the real world when they come into contact with the drug or when they find themselves in situations where they used to abuse drugs, like at a party.
- In the virtual worlds visited during treatment, people get support and ideas to help them recognize and conquer their cravings.
Research shows that when recovering people develop strategies to avoid relapse in a virtual world, they are able to take those strategies and use them in real-world situations.
Researchers are also exploring virtual reality therapy as a way to help people with eating disorders, like those that lead to obesity. Many scientists believe that some people become obese because they are addicted to food. Food addiction may be similar to drug addiction, where food triggers reward signals in the brain and makes people who are addicted to food crave it even if they aren’t hungry. Virtual realities might help people develop strategies to overcome their food cravings.
Have you ever taken a skill you learned in a video game and used it in the real world? Tell us in comments.
Your school probably has science classes like biology and chemistry and maybe even ecology, but does it offer a class specifically on neuroscience?
Neuroscience is a branch of biology that focuses on the body’s nervous system—which includes the spinal cord, nerves, neurons (nerve cells) and, of course, the all-important brain.
Work in the neuroscience field is varied and exciting. Neuroscientists might study how messages travel from one area of the brain to the other, or they might focus on how the brain is involved in behavior and decision-making.
Still others might work to find causes of and cures for diseases and medical problems like stroke, Parkinson’s disease, depression, Alzheimer’s disease, schizophrenia, and addiction.
At NIDA, research focuses heavily on neuroscience, considering that drug addiction is a brain disease. Without neuroscientists and the research they do, we would be unaware of some pretty important things—like how the brain isn’t fully developed until a person is well into their 20s and how drugs like marijuana affect the teen brain differently than an adult brain.
So much about the brain is still unknown. That makes neuroscience a particularly exciting field. If you are interested in help shed light on the mysteries of the brain, consider exploring neuroscience as a career. Check out the advice NIDA scientists offered to SBB for teens interested in a future career in science.
Learn more about the brain from these NIDA resources:
“We always start with a question…”
We love getting the comments you send us in response to important or controversial posts. As you know, Sara Bellum has the opportunity to interact with some of the world’s most renowned researchers to understand more about drug abuse and addiction. Since many of you have commented on blog posts questioning the science or wondering how NIDA scientists reach their conclusions, we invited NIDA’s Director, Dr. Nora Volkow, to talk about how scientists go about the process of discovery. Dr. Volkow explains:
In scientific research, we always start with a question. It could be something monumental—like setting out to map every neuron in the human brain to help determine its precise structure—or something that applies in only certain cases—like why do some people get addicted to drugs more easily than others?
Once we have a question in mind, we investigate existing research to see how others have looked at the question, or maybe even answered it. Sometimes, this helps a researcher refine the question or discover whether other conclusions could have been drawn from existing data.
Science is about testing and retesting our assumptions
Based on current research on differences in addiction between individuals, we might look through data to identify common features for drug-addicted persons: are they based on a family history of addiction? Are there environmental factors like the availability of certain drugs? What about mental health considerations?
From there, we would form a hypothesis. For example: “In certain individuals, heredity is a factor in drug addiction.”
Then we would devise a way to test that hypothesis in an experimental group vs. a control group. The only way we can verify results is to have someone else conduct the experiment independently and replicate the findings. Science is about testing and retesting our assumptions. Only then can we call it a science-based fact.
So, you can see that scientists are, by nature, curious about why and how things work. Maybe you’ve been curious enough to do a science experiment yourself?
Maybe you’re like teens Daniel Martin, Jada Dalley, and Sehar Salman, who all found themselves pursuing scientific mysteries: Daniel wondered if he could prove the urban myth that scavengers in the deserts of the Southwest will not touch human remains with even a trace of methamphetamines in their bodies. Jada and Sehar examined tsetse flies (a common experimental source for scientists) to discover something completely new: effects of third-hand smoke. They searched for answers using the scientific method Dr. Volkow describes above, and designed research projects that earned them a 2009 Intel International Science and Engineering Fair (ISEF) Addiction Science Award.
Check out ( PDF [586 KB] ) what Daniel, Jada and Sehar found, and how they reached their conclusions.
Keep asking questions.
Hi, my name is Eric Wargo and I’m a new science writer here at NIDA. Before coming to NIDA, I wrote for an association of psychological scientists, people who study all aspects of the mind and human behavior. I was excited to come to NIDA, because NIDA scientists study the brain, and the brain is at the root of everything we humans do.
The brain is almost like magic: It has the ability to transform thoughts and feelings into real physical actions and physical states like health or illness. And something as simple as an idea or a belief can have a real effect on your well-being or how well you do in school or in your relationships. I’ve always been especially interested in ways people can improve themselves—and even achieve many of the things some people seek through drugs—through activities that change their brains. SBB asked me to write some guest columns on this topic. I hope you enjoy them!
Learning Changes the Brain
If you’ve been reading this blog, you know all about how drugs change the brain. But lots of things besides drugs change the brain, and lots of those brain changes are good.
Learning is the #1 positive thing that changes your brain. Something as small as a new experience or learning a new word rapidly creates or reinforces new connections between neurons, even hundreds or thousands of them, in real time. You aren’t exactly the same person now, after reading the last sentence, as you were before you read it—because your brain changed a little.
And guess what—just knowing that fact can actually make you smarter.
Challenge Your Mindset
A few years ago, I was blown away when I heard a really amazing lecture by a psychologist named Carol Dweck. She has studied how people’s “mindsets”—specifically the beliefs they hold about whether someone’s intelligence is changeable—have a strong effect on how well they succeed in school and in life. People who think that intelligence is just something you are born with (or not) don’t apply themselves as much when it comes to learning. Even if they are told they are smart, they may not try as hard and actually may not ultimately achieve as much or handle challenges as well as those who believe that smartness depends mainly on how much effort they put in.
Dweck tested this idea with junior high school students. It can be a tough period in life, as you may have found out yourself. A lot of kids who were happy and did well in elementary school suffer setbacks when they hit junior high—they become frustrated and unhappy and stressed, and where they were once good students, they suddenly see their grades go down. In one study, Dweck and a couple of her colleagues found that students who held the “intelligence is changeable” mindset were more motivated to learn and actually performed better in math over the course of 7th and 8th grades than did those who believed their intelligence was a permanent, fixed quantity.
So Dweck and her team designed an intervention to help students whose math grades were falling. Over the course of 8 weeks, a group of these students were taught about how the brain works, including the way learning actually builds new and stronger connections between neurons and how the brain is like a muscle that can be strengthened through the exercise of learning. A comparison group also learned about the brain and study skills but without the emphasis on the brain’s changeability.
You can probably guess what happened: The students who learned about how their brains change actually reversed their plummeting math grades—they started doing better! Those who were not exposed to this idea continued doing poorly in math. (Dweck has now taken her intervention, called “Brainology,” and developed it for use by schools and teachers.)
The bottom line: Mindsets are super-powerful in setting people either on a path to success or on a path to something less. People who (correctly) believe their brains change go farther, do more, and adapt better to life’s challenges. So help spread the word to your peers: Your brain changes and you can choose how you change it.
Next time, I’ll talk about some cool things you can do to change and hone your brain.
Eric Wargo writes about the brain and addiction for NIDA’s Office of Science Policy and Communications. He has a Ph.D. in anthropology, and in his spare time, he writes and blogs about science, history, movies, and other cool topics.
Regardless of whether or not teens should care about body image or physical appearances, the truth is that we do care, a lot. And working out is a healthy way to look and feel better. The trouble comes when people sacrifice their health to look buff—like by taking steroids.
While not that many teens try steroids even once, according to NIDA surveys (about 3 in 100), those who do use steroids are getting a lot more than just larger muscles. Steroids can cause acne and make your hair fall out. They can also damage your heart and change your hormone levels so that girls might grow facial hair, and boys could develop breasts. Seriously. NIDA scientist Dr. Baler reveals more about what steroids can do in the video to the right.
Alcohol companies have tapped into a growing market to introduce underage drinkers to their products, on the basis that kids who acquire a taste for alcoholic drinks early are more likely to get hooked. While it is still illegal for teens to purchase them, “alcopops,” are flavored beer and vodka drinks that contain caffeine, juices, and other flavors. These drinks often sport names like Moonshot, JungleJoose, and Bacardi Breezer Watermelon, to fool you into believing they are harmless flavored drinks.
But Drinker Beware…
Alcopops may contain 4-7% alcohol or more, higher than the average can of beer containing a little over 3% alcohol content. Alcohol is a depressant, and so can make you tired and slow your brain and reaction time. That affects your ability to make decisions and to act or think properly—it also makes you thirsty, so you keep drinking. Now throw in a strong jolt of caffeine, such as you find in typical energy drinks. While the alcohol in alcopops tends to make you sleepy, the caffeine in them keeps you feeling “up.” Sugar, the major ingredient in many juice drinks and flavorings, also stimulates your brain to give you a short-term energy surge. Now confused from the caffeine, alcohol, and sugar mix, your brain gets tricked in sometimes lethal ways because these drinks don’t taste like alcohol and make you feel less intoxicated than alcohol alone. This leaves you even less aware of how much you’ve consumed and more likely to binge drink.
What’s the Big Deal?
The big deal here is that combining a depressant (alcohol) with stimulants (caffeine and sugar) sends mixed signals to your brain, which can have long-term consequences. So digest the facts before you pop a top: drinking alcohol—including alcopops—can be quite dangerous.
Have you ever noticed all the different emotions you experience in a normal day? For example, you can feel happy in the morning when you find out you passed your bio quiz, grumpy at noon when you haven’t eaten since breakfast, and then sad when the football team loses the big Homecoming game.
Chemicals called neurotransmitters, which carry messages across the gaps between neurons in your brain, influence your changing mood. One neurotransmitter, dopamine, increases alertness and makes you feel happy when something good happens. Lots of abused drugs raise a person’s level of dopamine.
Serotonin, another neurotransmitter, affects the brain in a different way. Known as the “calming chemical,” serotonin eases tension and stress. It lifts a person’s mood, lessens anxiety and aggression, promotes sleep, and also affects appetite, memory, and perceptions.
“It’s a molecule involved in helping people cope with adversity … to keep going and try to sort everything out,” says Philip J. Cowen, a serotonin expert at Oxford University and the Medical Research Council. To quote his Manchester University colleague Bill Deakin, “It’s the ‘Don’t panic yet’ neurotransmitter.”
Serotonin also puts a brake on the excitement and sometimes recklessness that dopamine can produce. When the overall brain chemical system is working well, it seems that these chemicals interact to balance out extreme behaviors. That’s why it can lead to problems when a person takes illegal drugs that affect serotonin or dopamine.
Many different drugs affect serotonin levels in complex ways. For example, when a person uses MDMA (Ecstasy or “Molly”), serotonin increases in different parts of the brain, causing elevated mood and feelings of empathy. Some studies show that elevated serotonin from illegal drug use plays a role in the person wanting to take more of the drug, possibly leading to addiction.
For more information on how drugs affect brain chemicals, check out NIDA’s article, Impacts of Drugs on Neurotransmission.
Dr. Frascella: At NIDA, we’re interested in how drug abuse affects brain and behavior, so we can learn how to better prevent and treat it.
We’re finding out that all drugs of abuse change the brain. Our task as scientists and researchers is to try to figure out 1) How to prevent the use of drugs that change the brain, and 2) Once the brain has been changed, can we change it back to normal?
We know generally that drugs change the brain in ways that result in some dysfunctional behaviors.
SBB: What does that mean?
Dr. Frascella: Well, for instance, addiction is characterized by compulsive drug seeking and drug taking. That means once you start [abusing drugs], you often can’t stop, even if you want to. That is because your brain has been changed in ways that “hijack” your self-control. So although your initial decision to take drugs was a voluntary behavior (maybe you thought you’d try them out once or twice), it ends up being compulsive behavior, where you are driven to repeat drug use again and again.
Over time, if you keep taking drugs, you’re no longer in control. The drug-seeking urges or drug cravings become so strong that you can’t stop.
SBB: Is marijuana one of those drugs that can hijack the brain?
Dr. Frascella: It certainly could. There are plenty of people who start out smoking pot recreationally. Some people may try it to be “cool” and have fun with their friends. They like it so much, they keep doing it. But 15 to 20 years later, they’re still smoking marijuana every day, once, twice, or three or more times a day. They can’t go to sleep without it; and they have trouble with thinking and remembering things. It becomes a big problem in their lives.
SBB: Does smoking pot have any unique effects when you’re a teen?
Dr. Frascella: We know that the teenage brain isn’t fully developed in areas where making decisions and exercising good judgment (the frontal areas of the brain) are involved. Adding drugs of abuse further compromises those same brain areas, so it’s like a “double whammy.” Because the brain isn’t fully developed, drugs can have a greater effect on it and cause the brain not to function properly.
If you think about a car, drugs push the “go” system, the gas pedal. The frontal areas of the brain are like the braking system. Those brakes are not fully developed, and the drugs are pushing on that accelerator without having brakes. We really need those frontal brain areas to help us weigh two sides of a decision properly and consider the consequences, which we don’t tend to do when we’re young and feeling like nothing can hurt us.
SBB: So we’re speeding through life with no brakes, and whatever is in front of us gets mowed down?
Dr. Frascella: Well, hopefully not. Hopefully we aren’t without any brakes. Our research at NIDA is to figure out ways to enhance those braking systems and come up with therapies that can help teenagers and adults who want to take back their lives from the grip of drugs.
*Note: In order to listen to the podcast, you will need to have a media player on your computer.
I’ve always been a huge Star Trek fan. When I was a teenager, my hero was Mister Spock—cool, analytical, even-tempered, and smarter than everyone around him. Being raised in his ancient society of the planet Vulcan made him a force to be reckoned with. He was kind and compassionate, but his mind was unswayed by human passions and fears, and he was always in control. When he was alone, he often sat, eyes closed, deep in meditation.
Vulcan is a fictional planet, but I later came to learn that there are real people on Earth kind of like Mister Spock, who possess many of his qualities and abilities because they have trained their brains in ancient Eastern mental arts.
Going to a “Zen Place”
A German philosophy professor named Eugen Herrigel discovered the power of a calm mind when he went to Tokyo in the 1920s. One day, he was having lunch with a Japanese colleague when an earthquake struck. Panic quickly broke out, and most of the diners (including Herrigel) jumped up and hurried out of the restaurant.
But the man Herrigel was having lunch with remained seated with his hands folded, his eyes nearly closed, completely undisturbed by the shaking going on around them. Fascinated by his companion’s trance-like calm, Herrigel sat down too and felt strangely safe. When the earthquake was over, the man continued the conversation exactly where it had broken off, saying nothing about what had just happened.
A few days later, Herrigel learned the source of his lunch partner’s amazing, infectious calm—he was a Zen Buddhist. His emotional steadiness came from practicing meditation.
Buddhist literature is full of stories of people achieving amazing feats of insight, courage, and even control over their own bodies after years of practicing simply sitting and focusing their minds. Such people often become rocks of support, giving strength to those around them, or even become calmly inspiring leaders themselves.
Meditation’s Effects on the Brain
Brain scientists have gotten really interested in the effects of meditation on the brain. A Harvard psychologist named Richard Davidson has done brain scans on dozens of Buddhist monks and found that their training has permanently altered their limbic systems, giving them heightened empathy—or the ability to understand and identify with another person’s feelings.
A recent study of “beginner” meditators by another Harvard researcher found that 8 weeks of training in techniques like mindfulness meditation and yoga increased gray matter in brain regions involved in memory, learning, emotion, breathing, and motor control.
[Caption: These high-resolution brain image scans show where gray matter increased in different parts of the brain for those who practiced mindfulness.. A: The posterior cingulate cortex and cerebellum; B: The left temporo-parietal junction; C The cerebellum and brainstem.]
The bottom line is, the brain is a powerful instrument, and you can make it do even more amazing things when you sharpen and enhance its powers. Wouldn’t it be cool to have a tough, disciplined, compassionate, and fearless brain like a Buddhist monk … or Mister Spock? P.S. After his remarkable experience with the Zen man in the earthquake, Eugen Herrigel promptly decided to learn Zen himself, and went on to study with a Zen master for 6 years. He then wrote a classic book about his experience, called Zen and the Art of Archery, as well as a short introduction to Zen philosophy and meditation (which I highly recommend, if you are interested) called The Method of Zen.
Eric Wargo writes about the brain and addiction for NIDA’s Office of Science Policy and Communications. He has a Ph.D. in anthropology, and in his spare time, he writes and blogs about science, history, movies, and other cool topics. Read his previous SBB guest post, Mindset Over Matter.
Our bodies can do lots of things without us even thinking about it. And that’s what the Word of the Day is about. The brainstem, not surprisingly, is a “stem” that connects the brain to the spinal cord. Its basic functions include directing heart rate, breathing, arousal, and sleeping. Lucky for us, the brainstem does all these things automatically. That’s why you don’t forget to breathe when you’re asleep!
How? The brainstem directs the spinal cord, other parts of the brain, and the body to do what is necessary to maintain our life.
The brainstem is one of the more primitive parts of our brain—it dates back to the age of the dinosaurs! Just like another primitive part of our brain, the limbic system.
One of the reasons that addictive drugs exert such powerful control over our behavior is that they act directly on our primitive brainstem and limbic system.
For more brainy words, check out the NIDA for Teens glossary that fuels SBB’s words of the day.
Did you ever wonder how scientists develop medications to help people stop smoking? High School Junior Ameya Deshmukh has been wondering about that since he was 7 years old. Because his parents work in science labs, he began learning about basic science from an early age. Now at age 16, he just won the first place NIDA Addiction Science Award at this year’s Intel International Science and Engineering Fair.
For his project, Ameya decided to search a database of 10,000 molecules to find one that will bind to nicotine receptors in the brain. Those are the cells that nicotine molecules attach to and then cause their addictive effects in the brain. If we can learn how to link up the right molecules with the right receptors—say, by developing a special medication with that would go right to nicotine’s “sweet spot” in the brain—then we could block the pleasure that people get from cigarettes. A lot of lives might be saved, since 440,000 people in this country die every year from tobacco-related diseases. This includes 35,000 who die from exposure to second-hand smoke. UGH!
Because identifying the right molecule can be like finding a needle in a haystack, Ameya used what is known as “rational drug design.” He first selected molecules based on previous research. Then he used computerized models to narrow the list of potential compounds even more. Finally, he tested the short list of molecules on human cells to identify which ones would bind to the receptors. With more research, Ameya’s work could point to new directions in developing medications to help people quit smoking.
When talking to the judges, Ameya stressed how important it was to develop these medications. In 2009, 20.1 percent of 12th-graders, 13.1 percent of 10th-graders, and 6.5 percent of 8th-graders said they smoked in the month before the survey. Unfortunately, many will get addicted. The hard part is quitting, as seen in the nearly 35 million people who make a serious attempt to quit smoking each year, with most starting up again within a week. So promising new medications are sorely needed.
NIDA’s Addiction Science award is given at the annual Intel International Science and Engineering Fair (ISEF), which was in San Jose this year. For more information on NIDA’s 3 winners, see NIDA’s news release at http://www.nida.nih.gov/newsroom/10/NR5-14.html
Are there serious public health problems that you could address in a science project?
Doodle Jump. Candy Crush. FarmVille. Angry Birds. Cut the Rope. Fruit Ninja. Words With Friends.
Nearly everyone with a smartphone or tablet has played one of these video games. It’s easy to get swept up in the bright colors, cutesy characters—and the satisfaction you feel when you finally complete a difficult level. So you keep playing, and playing, and playing. Lots of people say games like these are “addictive.” But, are they, really?
Maybe. Addiction Science Award Winner Ethan Guinn definitely thought so.
Dopamine: Sweet Rewards for the Brain
Rewards in video games, such as points or bonuses, are surprising and often unpredictable. Figuring out that special move or combination that helps you conquer each level feels great. Not knowing when you’ll get that reward keeps you engaged.
These periodic bursts of pleasure are the work of dopamine. Dopamine is the chemical in your brain that causes you to feel happy, and it is what gets you hooked on lots of things in life.
Your brain is designed to release dopamine in response to things that are good for you—like spending time with your friends, eating healthy food, or exercising. Dopamine bursts also reward you when you apply your cleverness to solving real-world problems.
But people have figured out all kinds of ways to tap into the brain’s reward system with things that aren’t so good for you. Drugs and junk food are obvious, harmful examples. Video games might not kill you or make you overweight (at least not directly), but many people feel they are “hooked” on them.
So, Is Gaming Really an Addiction?
Scientists say that more research is needed before they can tell whether being hooked on a video game is actually an addiction.
Addiction is more complicated than just wanting to feel good. People who are addicted to drugs often just want to feel “normal” or not bad. It’s also more than just the compulsive need to keep using a drug or engaging in a behavior. Addiction means being unable to quit, even in the face of negative consequences.
A person with a drug addiction wants to use drugs even when their grades have tanked, they’ve lost their job, and they no longer care about the things that were once important to them. When they aren’t using drugs, they feel withdrawal symptoms that make them sick. Scientists aren’t sure video games can cause the same effects.
But … if you play a game so much that you don’t participate in life’s normal activities—you don’t sleep or eat or hang out with friends or do the things you used to love—you are heading down a dangerous path. If that describes you, maybe you should try not playing the game for a day or two, or even a week. Ask people that you trust if they think you have a problem. And, if you find that you just can’t stop—even if video gaming addiction isn’t officially a disease—you can absolutely get help by talking to your parents or a guidance counselor at school.
Tell us what you think in comments: Is video gaming addiction real?
At NIDA’s last Chat Day, we got this question from a high school student:
”Why do people scratch a lot when they are high on heroin?"
A NIDA scientist responded that he had done years of research on this topic. He explained: “Heroin activates connections in the brain called opioid receptors. These receptors then activate fibers that transmit itch information (aka ‘pruritus’) to the brain. Thus, heroin users feel itchy. Good question.”
But before heroin can activate opioid receptors, it has to enter the blood stream and reach the brain. So how does this happen?
People usually inject heroin into their blood stream with a syringe. Soon afterwards, the heroin crosses the “blood-brain barrier”—a protective membrane that separates circulating blood from brain fluid in the central nervous system. Once in the brain, heroin is converted to a chemical called morphine and binds rapidly to the opioid receptors already mentioned. These receptors recognize chemicals affecting pain, like morphine.
Heroin users typically report feeling a surge of pleasure, or a “rush,” which makes sense because heroin enters the brain so rapidly. This quality also makes it extremely addictive. Along with the rush usually comes a warm flushing of the skin, dry mouth, and a heavy feeling in the arms and legs, which may be accompanied by nausea, vomiting, and, of course, severe itching. Also, since heroin is a depressant, it clouds your thinking and can slow—or even stop—breathing.
Because heroin is mostly sold on the street, users can’t be sure of the purity (or strength) of the drug they’re taking. Also, because it’s so addictive, they may crave bigger and bigger amounts of the drug to get the same rush they got the first time—which often leads to overdose and death.
The brain controls just about everything we do, think, and feel. It coordinates all of the body’s physical functions—like standing, walking, and breathing—as well as our memory, emotions, and behaviors.
Managing all of those jobs requires 100 billion neurons, or brain cells. And those neurons have trillions—yes, trillions—of connections through synapses, or routing switches that control how these nerve impulses travel around the brain and through the body.
With so much going on in that tightly packed space between our ears, it’s no wonder the brain requires its own field of scientific research—neuroscience.
“Brain science allows us to try and understand what makes us uniquely human and drives our behaviors and response to others,” says NIDA Director Dr. Nora Volkow.
NIDA Interviews Neuroscientists
To spotlight researchers whose work is advancing the science of the brain, NIDA interviewed several top neuroscientists investigating drug abuse and addiction. Four scientists in this group of video clips talk about what attracted them to study the brain—and all are obviously excited about how their research is increasing our knowledge about the brain and how drugs affect it.
Have you ever considered a career studying the brain?
NIDA scientists are always saying that teens shouldn’t use drugs, tobacco, or alcohol. But do you know why they say that? Because of scientific studies like this one by Dr. Jay Giedd, which shows that your brain won’t reach its adult potential until you’re over 20 years old. If you’re a teen—even if you’re a high school senior—your brain is still maturing. Your neurons are still developing, and connections between different parts of your brain are still forming. Drugs and alcohol may mess up that process.
Along with his colleagues at the National Institute of Mental Health, Dr. Giedd created this scientific figure.
This picture is a cartoon depicting how the human brain continues to change between the ages of 4 and 21 years. As you move from left to right along the red arrow, the brain gets older. Above the arrow are side views of the brain (as if someone was standing in front of you, looking toward your right shoulder). Below the arrow are views of the brain from the top (like you are looking down on someone’s head).
So what’s with the rainbow colors? The colors represent the amount of “gray matter” (or active brain cells called neurons) that the researchers found in brains of different ages, using a brain imaging technique called MRI. Gray matter isn’t usually this colorful (hence the term ‘gray’ matter), but these brain pictures have been color-coded to show areas of more or less gray matter. Pink and red areas have the most gray matter, while green and blue areas have the least.
So, who do you think has more gray matter—you, or your parents? What does the figure show?
Yep—you do! It turns out that the number of neurons in your brain actually decreases as you get older. Younger brains have more gray matter (represented by the pink and red areas) than older brains (which are more green and blue). But wait—if the number of neurons in your brain is going down as you age, does that mean you’re getting dumber?
Fortunately, no. The total number of neurons in your brain isn’t as important as how your neurons connect to each other. As you get older, everything you learn and experience shapes the connections between the neurons in your brain. Over time, the connections between neurons become stronger. Your brain also develops more myelin—a white substance that wraps around neurons, insulates them, and helps them communicate more effectively. It’s like starting with a blob of clay and carving it away to make a sculpture: eventually you get a sleek, smart, mature adult brain, like the blue brains on the far right of the figure.
This figure also shows which parts of the brain mature first and which mature last. One of the very last areas to develop is the prefrontal cortex—the part of the brain located just behind your forehead. This part of the brain is responsible for helping you make good decisions, and isn’t fully mature until well after you graduate from high school! Scientists think this might help explain why teens tend to take more risks than adults, including experimenting with drugs.
Does all this mean that teens can’t make smart decisions? No. Teens can and do make good choices all the time. What this figure shows is that your brain doesn’t reach its full potential until you are in your mid-twenties. Basically, teenagers have a lot of brainpower still to come online—good reason to avoid stunting your potential brain power now with drugs or alcohol.
Watch some cool time-lapse movies showing how the brain changes with age.
You may remember hearing something about neurons in biology, but what about today’s word of the day: axon?
Neurons are nerve cells in the brain that communicate with each other 24/7 to control everything we do, think, and feel. The axon is the long, tunnel-like part of the neuron (see picture) that steers messages from the cell to other nerve cells or body tissues, such as muscles.
Since the axon’s only job is to transmit messages from point A to point B, it can focus on doing it fast. For this reason, many axons are lined with a fatty material called myelin, which helps the message glide through the axon quickly. Prolonged drug use can damage the axon or the myelin, causing noticeable changes in a person’s behavior over time.
For example, scientists have discovered that abusing certain drugs on a long-term basis—like inhaling fumes or markers—can eat away at myelin. Without its protective myelin lining, the axon itself is more vulnerable to harm. An axon that is damaged or is missing myelin cannot transmit messages as well to other nerve cells, if at all. For someone with damaged axons, this can mean muscle spasms, tremors or difficulty with basic motor skills, like walking, bending, or talking.
Science has just revealed … (wait for it …) You need your whole brain!
Sounds obvious enough, but it’s not uncommon to hear people say, “He’s awesome at taking tests, he must be left-brained.” Or, “She’s a really good painter—she must be right-brained.”
In fact, until recently, many people thought that artistic skills were mostly processed in the right side of the brain and analytical skills were mostly processed in the left side of the brain. This led people to believe that creative thinkers were “right-brained” and logical thinkers were “left-brained”—almost the same way that most people are right- or left-handed. It was a simple way to explain why someone might be better at solving word puzzles than their friend who prefers to doodle amazing pictures. It was an “easy answer.” But it turns out, it wasn’t right (or left!).
A study that looked at 1,000 brain scans found that while certain regions in each side of the brain are responsible for certain types of tasks, the right side of the brain is no more creative than the left, and the left is no more analytical than the right.
The truth is being good at math requires both sides of your brain. You use the left side to count and memorize formulas and the right side to estimate sizes and shapes. So, you need both sides of your brain to pass geometry!
The lead researcher on the brain study said that individual talents seem to depend on connections that are formed between all regions of the brain—left, right, and center. The number of connections, or synapses, in our brain is mind-blowing: There are literally trillions (trillions!) of connections among billions of neurons in our brains. Each connection does its work to make each person unique—with different interests, strengths, personalities, and challenges.
This complexity helps to explain why there is still so much we don’t know about the brain, the impact of drugs, and why some people become addicted and others don’t, and why some recover and others don’t. It’s a reminder of how important it is that we protect our brains, keeping them healthy and drug free. Read more about how drugs can change your brain.
Tell us in comments: Are you a more creative or logical person? How would drugs interfere with your strengths?
You may think you know what addiction is—lots of people have many different opinions about addiction and different ways of defining it. Here are some myths you may have heard:
- Getting over addiction to drugs is a choice.
- In order for treatment to work, the person has to hit “rock bottom.”
- People have to choose to get treatment or it won’t be effective, such as when a judge sends a person to treatment facility instead of jail.
The truth is that addiction is a complex brain disease that scientists are still figuring out. For instance, one person may use a drug once or many times and nothing bad happens, while others may overdose with the first use. Some people use drugs regularly and never become addicted, while others try drugs once or twice and do become addicted. There is no way of knowing in advance how a person may react to these dangerous substances. Whether or how quickly addiction takes hold in individuals depends on many factors, including:
- Genes: Research shows that some people’s genes may leave them more susceptible to addiction than other people’s.
- Environment: Kids who are exposed to drug use in their families or neighborhoods are at greater risk of engaging in drug abuse themselves.
- Age at first use: The younger a person uses drugs, the more vulnerable he or she is to addiction in adulthood. Since the brain continues to develop well into a person’s twenties, using drugs in the teen years can set a person up for later drug problems.
What scientists know for sure is that many drugs “turn on” the brain’s reward circuit, which is part of the limbic system. The person then learns to associate the drug with pleasure and starts to crave it more and more, leading to compulsive drug use and often to addiction. In an addicted person, the brain changes in ways that cause compulsive drug seeking and use, despite negative consequences, so even if they want to quit, they can’t without treatment and support. That’s why addiction is considered a brain disease. Other activities in life also activate the brain’s reward circuit and can cause “driven” behaviors, such as compulsive overeating or video game playing. However, scientists are still trying to figure out why this happens in non-drug contexts—it may be connected to dopamine levels in the brain. Learn more about the science behind drug addiction by visiting http://nida.nih.gov/scienceofaddiction/.