These questions were answered by more than 50 individual scientists and science writers with expertise in addiction. To get as many answered as possible, responses were written quickly based on the personal background and knowledge of each expert. Please note that there was not a secondary review or proofreading of each fact, and if readers have questions or comments about any response, they can ask further questions.

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How do you know if you're an alcoholic?


Hi good question! A person is considered an alcoholic when they cannot control the amount and frequency of alcohol use. That is, the person uses alcohol in situations that can put him or her at risk or in danger, for example, while driving a car. A person is also considered an alcoholic if they use larger amounts than what they intended to use, when alcohol affects his or her social, family, work, or emotional life, or continues to use alcohol in spite of knowing that it causes them medical or psychiatric (mental) consequences. The American Psychiatric Association publishes the Diagnostic and Statistical Manual of Mental Disorders (DSM) which has the diagnostic criteria for alcohol abuse or dependence. For more information on alcohol and resisting peer pressure go to Thanks for your question! Keep them coming!

-Ivan Montoya

how do you know when you've drank too much alcohol?


That is a great question. One of the problems with drinking alcohol is that it affects your judgement as you drink it, so you are less able to tell how it is affecting you. But you might notice that you more sociable at first, and with continued drinking, you may find yourself talking more loudly or behaving in an inappropriate manner. Some people become sleepy or argumentative or aggressive when they continue to drink, and your ability to make reasonable decisions deteriorates. You can find more information at

-Nancy Pilotte

How do you prevent people from smoking and what should that person do to stop smoking?


Well there are a lot of approaches to prevent tobacco use. We know that kids who have good social and academic skills and supportive non-smoking home environments are less likely to start smoking. So a lot of prevention programs work with kids and families to develop these skills. Many tobacco interventions are what we call policy interventions. These are things like training clerks in stores to card kids to prevent them from purchasing, and raising taxes on cigarettes so much that they become unaffordable for kids. There are also many approaches for quitting smoking, unfortunately smoking is a very difficult addiction to break. At this point a combination of social support through quit phone lines, quitting clinics and family support in combination with nicotine replacement therapy seems to be the most effective approaches. The best approach of course is to never start smoking.

-Liz Robertson

How do you say no?


It's really tough, especially when you're a teenager. One of my kids never did drugs. He just told people that he did not want to have to admit to doing something later in life that people would think less of him for.I remember when I was a teenager that people offered me heroin and speed. I just was not interested and told them so. Anybody who persists and keeps bugging you isn't really your friend.

-Frank Vocci

how do you study drugs


We can study abusable drugs from many different angles. I am a geneticist, that means that I study how the use and abuse of drugs is affected by genetic differences among different people. There is actually a lot of research in the area of genetics of drug abuse. For a good resource on this, check out:

-Joni Rutter

how do you tell if someone is on drugs


You can't always tell, but some tell-tale signs are red eyes, slurred speech, walking funny, not finishing sentences, seeming too sleepy in the middle of the day ( heroin) or being jumpy (speed or other amphetamines). Also, if a person is compulsively seeking and using a drug despite negative consequences, such as loss of job, debt, physical problems brought on by drug abuse, or family problems, then he or she probably is addicted.T o learn more, check out "The Science of Addiction" at

-Frank Vocci

How does a drug test work?


There are several types of drug tests, but the most common uses a urine sample. In these tests, a sample is exposed to various antibodies for drugs. If a drug is present,usually an indicator on the test will change color or give some other visual sign that you have tested positive.You can find out more about drug testing at:

-Steve Gust

HOW CAN I TELL IF MY FRIEND IS DOING DRUGS?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!? WORRIED


From you question, I am guessing that you have observed signs or changes in your friend's behavior that lead you to suspect they are using drugs. I suggest that you talk with you friend about your concerns. NIDA's website has many resources for teens to help them learn about the effects of using drugs and how they can find help.You can find out more about that at: You can also find information about specific drugs and their unique effects, e.g. For more information about marijuana, go to For more about club drugs go to:

-Cora Lee Wetherington

How can I tell if someone is on drugs?


not always. people that have taken drugs for long periods of time can hide the effects very well

-Nora Volkow

how can new born babies be addicted to crack at birth


When a mother takes a drug, like crack or nicotine, that drug can be passed on to the baby through the placenta. The level of the drug in the baby can be high enough for the baby to show signs of withdrawal from the drug when they are born. Some babies born to mothers who have have abused crack during pregnancy are born prematurely and are smaller than babies born to mothers that didn't use the drug. For more information on the effects of crack, see

-Larry Stanford

How Can Presriotions Drugs Be So Addictive If They Are For Your Health?


Prescription drugs have been tested to establish what good and bad effects the drug has, and how much of the drug you can take before the drug starts having bad effects. That is why prescription drugs have to been given under a doctor's supervision. Prescription drugs can be addictive when taken in amounts greater or more frequently than a doctor would permit. You can find out more about that at: and "The Science of Addiction" at

-Steve Grant

How can snorting cocaine give you nosebleeds or make you lose your sense of smell?


Cocaine affects the blood vessels in the nose by making them narrower. When this happens the membranes in your nose are damaged for lack of oxygen. If that were not bad enough, cocaine increases blood pressure. The two together combine to give the user nosebleeds. In addition, the nerve cells that are responsible for the sense of smell also suffer from lack of oxygen and become impaired in their ability to send proper odor signals to the brain.

-Barry Hoffer

how can u get addicted to food if the are not drugs

-go nc,

we are not certain that food can produce addiction but we know it can produce very strong habits that are very difficult to break. this is because food like drugs increases dopamine in brain producing pleasure

-Nora Volkow

how do medicines work differantly than drugs?


all drugs of abuse increase dopamine in the brain which is a chemical involved with pleasure. Very few medications increase dopamine but there are some that do. When a medication increases dopamine it can also produce addiction.

-Nora Volkow

How do people get addicted to drugs?

-XxhoundgirlxX, Texas

Thanks to scientific advances, we know quite a lot about how different drugs act on the brain. All drugs of abuse increase the release of a neurotransmitter (a brain chemical used to send signals between nerve cells) known as dopamine in the brain's pleasure centers. With continued use the release of dopamine becomes totally out of control. Individuals are then at risk of becoming addicted to this effect and start to take the drug without even thinking about it. Eventually, drugs of abuse can affect your capacity to make good decisions and learn new things. In many cases, the drugs can mess with your brain so much that you can literally lose control of your life.This is why we say that drug addiction is a brain disease, and stopping drug abuse after you start is hardly a simple a matter of will power. To learn more, check out "The Science of Addiction" at

-Joni Rutter

how do u feel when you don't have your drugs for a long period of time?


Interesting question! What you feel depends on the type of drug. When a person does'nt have addictive drugs for a long time they can experience what is called a Withdrawal Syndrome. The syndrome is often characterized by overactivity of the bodily functions that are suppressed by the drug and/or depression of the functions that are stimulated by the drug. Usually, this syndrome is characterized by signs and symptoms that make the person look like he/she is really sick and sometimes the person has no choice other than to use the addictive drug seeking relief of the syndrome and that way he/she relapses. For more information please go to Thanks for your question!

-Ivan Montoya



science has shown that you can do this voluntarily or involuntarily. voluntarily, the person needs to be motivated to stop taking the drug and seek treatment. involuntary treatment also works as when individuals are ordered into treatment by the court system. in this case they are assigned to a treatment program and monitored very carefully. during treatment it is very helpful to have the family involved in the process and supporting the person while they go through the treatment process.

-Nora Volkow

How do we know that Marijuana destroys brain tissue?


We do not have evidence that marijuana destroys brain cells--although it does interfere with thinking and learning while someone is high and sometimes for a few days after. Marijuana use has also been associated with a number of mental conditions, including schizophrenia (psychosis), depression, anxiety, and suicide attempts.Scientists do not yet know whether using marijuana causes mental illness. Evidence does show that frequent use is linked to psychosis (disturbed perceptions and thoughts) in some people, and can make these symptoms worse in patients who already have schizophrenia. Young users and those who are dependent on marijuana may be especially vulnerable. For more information about marijuana, go to

-Barry Hoffer

how do you get depressed?


we do not know exactly but believe that there is a chemical imbalance that triggers depression--chronic use of certain drugs can also lead to depression

-Nora Volkow

How do you get your parents to stop smoking?


I can relate to this, because when I was young, I wanted to get my mother to stop smoking! In those days, there wasn't much available in terms of effective treatments to help stop smoking. Now, there is so much help available!Smoking involves addiction to nicotine, but it also involves breaking strong habits. People get very used to smoking at certain times of day, in certain situations.Behavioral treatments help people learn to break the habit of smoking, and medications can help with the nicotine addiction. So combined behavioral treatment and medication can be very effective. For more information about how to stop smoking, take a look at this website: Perhaps if you let your parents know that you're concerned,and that there are effective treatments available, they might be willing to try to stop. If they're not quite ready, or if they fail, you can let them know that many people fail, or even fail repeatedly before they succeed, but that success is possible. Good luck!

-Lisa Onken

How do you help someone who uses drugs stop?


The best way for someone to stop using drugs is to get treatment from a doctor, therapist or support group. The sooner they get treatment the better are their hopes for recovery. For more on treatment and where you can find it, you can call the Substance Abuse Treatment Facility Locator at 1-800-662-HELP or go to their website at Because talking with someone about their drug use can be uncomfortable, it might be helpful to ask someone to help you, like a trusted family member, teacher or coach.

-Melissa Riddle

How are fertirnal and identical twins made? I am a sixth grader, so i am sorry for the spelling


I not a 6th grader and I mispel all the time! Fraternal twins are twins resulting from two different sperm cells fertilizing two different eggs. Identical twins result from a single fertilized egg that then splits into two. The identical twins have the same exact DNA; not so the fraternal twins.

-Joni Rutter

How big of an effect does cough med. have on people that use is a lot to get high?


there's a chemical in many cough syrups called dextromethorphan that can negatively impact a person's health. some of the effects include distorted perceptions of sight and sound and it can produce feelings of detachment - dissociation - from the environment and self.

-Nora Volkow

How big of an impact do drugs have on your mind, if only used once or twice?


Usually taking a drug only once won't have long-lasting effects, but taking drugs is always risky. The impact of taking a drug once depends on the drug, how much you take,and the circumstances under which you take it. Drugs like LSD and other hallucinogens have had profound effects on people's lives even after only one dose. Even if you have never taken an opiate drug, like oxycotin or heroin, if you take too much it can shut your brain down completely--and kill you.You can find out more about that at:

-Steve Grant

How can a person die from drugs?


there are many ways a person can die from drugs:they can overdose and die from respiratory depression or from seizures;they can die because drugs interfere with their reflexes so they end up in an accident;one can die from medical consequences such as lung caner or prostate cancer from smoking; or they can die from an infection contracted while injecting drugs. these are just a few examples. for more information on the consequences associated with drug abuse please go to

-Nora Volkow

How can amphetamine affect your body?

-Strawberry Shortcake,

amphetamine decreases blood flow in your body and thus can hurt the function of any organ in your body but particularly your heart and brain. amphetamine also produces addiction

-Nora Volkow

How can drugs affect your body?

-Groucho Marx,

Drugs affect your body in many ways. You can find out more about that at:

-Steve Grant

how can drugs affect your social life


Drugs can affect your social life when they become so important that you give up social things that are important to you. Drugs can also lead to problems at school (like getting bad grades) and with the police(like driving while intoxicated), which could limit your freedom to have a good social life. When you're high, you are generally more likely to make mistakes that could embarrass or even hurt you.Here's NIDA's Website for teens with information on the science behind drug abuse, facts on drugs, questions and answers, real stories and interactive activities.

-Kevin Conway

How does cocaine affect boys and girls differently?


What a great question. Unfortunately, at this time we have very little information on whether cocaine affects girls and boys differently, but there is evidence that girls may be much more vulnerable to developing addiction to cocaine than boys. For more information on cocaine, see

-Gaya Dowling

How does crack kiil you?


Smoking crack or injecting cocaine can directly affect your heart, producing an abnormal heartbeat. In some people this can make the heart stop. If that happens, death is just minutes away. Now, even if the person is lucky enough to get CPR and get resuscitated, that person is still at risk for brain damage.Seizures and stroke can also result from cocaine abuse.

-Barry Hoffer