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The NIDA Blog Team

You may know that smoking marijuana can pose risks for a person’s physical health and brain development, especially for teens. But did you know that, for some people, it carries risks for their mental health, too?

We don’t just mean short-term memory problems or poor judgment—those can happen for anybody who smokes marijuana. We’re talking about serious mental illness.

Researchers have found that some marijuana users have an increased risk for psychosis, a serious mental disorder where people have false thoughts (delusions) or see or hear things that aren’t there (hallucinations). But there is still a lot to learn about whether marijuana use may lead to this loss of touch with reality, or if having a mental illness makes people more likely to use marijuana. And as with other drugs, things like the age of users, how early they started smoking pot, the amount of the drug they used, and their genetics all could make a difference in whether or not long-term problems develop.

It’s not your jeans that matter—it’s your genes

Regular marijuana users with a specific version of a particular gene, AKT1, are at a greater risk of developing psychosis than those who smoke it less often or not at all. How much greater? For people who smoke marijuana daily, the risk is up to seven times greater.

The reason is that the AKT1 gene affects how much dopamine is released in your brain. Dopamine is one of our brain’s “feel-good” chemicals; it affects important brain functions such as behavior, motivation, and reward. When your brain releases dopamine (for example, after a beautiful bike ride or when you eat a delicious piece of chocolate), the release “teaches” your brain to seek out the same experience (reward) again. Some researchers believe that changes in dopamine levels are linked to psychosis.

Another study found that adults who used marijuana when they were teenagers and who carried a specific form of another gene for the enzyme COMT (which also impacts dopamine signaling) were at a higher risk of becoming psychotic.

Are you at risk?

Right now, unless you’ve had your DNA tested for those specific genes, you don’t know. Many health professionals believe that in the future most of us will know much more about our genetic makeup, but for now and for regular marijuana users, it’s an unknown risk—and you won’t know until you've developed an addiction.

Even if you don’t have those specific genes, there’s still a risk

A psychotic event can even happen to pot smokers without these specific genes that put them at risk for long-term serious mental illness. Although rare, marijuana-induced psychosis is becoming more common as people use higher potency forms, including edibles and oil extracts.

The bottom line? It’s important to know all the risks that can come with using marijuana.

Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.


A bunch of BS right there. AKT1 has been shown time and again to have little to no relative effect when mixed with pot. THC really doesn't affect it at all. There is no causal relationship between pot and psychosis. There is a correlative relationship. People who are psychotic but not undergoing treatment tend to self medicate with pot. The same is true of people who are depressed. The facts are simple and continued fear mongering by sites like this stigmatize people with false information.
because you can die form it and you get more of it and you can die a lot faster
There have been 0 reports of anyone dying after using marijuana so sit down
Tell that to my niece who was perfectly normal before smoking some "dank" marijuana and still not stabilized two weeks later. You're up in the night so stop kidding yourself.
You say at the end that although rare marijuana induced psycosis is happening more with higher potency. Is there a good reason that you don't site any study at all when you make this bold claim?

Hi Scott, thanks for your comment! We've added a link to this study in the text above: 

It's really interesting! 10x
We applied adjusted logistic regression models. W.T.F. That means they calculated the odds of psycosis on the data that they gathered then adjusted using a regressive algorithm to model the end result. I don't care how many names with Dr attached to it they got. If they are going to use that method to come to a conclusion about a biological process. They are on the wrong track. To many variables to point to anything definitive. I would say try again guys but this time do the actual research. Don't just crunch some numbers based on other people's diagnoses. You get skewed results that way. Again another Reefer Madness moment.
Denial. Playing Russian roulette
KJM, I suggest you too look into the newer research and be careful with not misrepresenting facts or minimizing health risks with marijuana use, regardless if "medicinal" (debatable) or not. This site is not intent on inducing fear, but to offer education and research on topics that affect our public health. FYI, rationalizing use is a sure sign of marijuana dependency; maybe you need to consult with a professional about signs of dependency.
I feel like this could have been written with a slightly less biased attitude. There's only a 1-sentance mention that folks with mental illness may be more likely to smoke, and then a lot of material suggesting a causative relationship (without actually saying it). All of the studies you have posted are correlation studies, and anyone who has ever taken Statistics 101 knows that you cannot infer causation from correlation. To do so is intellectually disingenuous. I see two possibilities that really should be included in any fair and balanced discussion of cannabis and psychosis: 1) the euphoria and relaxation caused by smoking provides relief to patients who experience high levels of anxiety or depression, both of which are highly comorbid with psychotic disorders (Buckley, Miller, Leher, & Castle, 2008), and so psychotic patients are self-medicating a preexisting condition instead of having it induced. The second possibility is that, for folks who are predisposed to psychosis, or have non-neurotypical dopamine signaling, the experience of smoking cannabis is, for whatever reason, more compelling than it is for a neurotypical person, so they are more likely to smoke for that reason. The study by Buckley et al was Psychiatric Comorbidities and Schizophrenia, published in the Schzophrenia Bulletin, 2008.
Your reference is outdated.
i think you could have been a little less biased. sorry but this was an awesome article. so shhhhhhhhh!!!!!
Wish I could have said that half as well.
What a joke
this was dumb and weird
this was so
Where's my Cheetos?
this is very helpful information for addictive, and marijuana.
There is no evidence to support the link between cannabis and psychosis. That's not to say they don't try to push it on you. They site recent discoveries that show structural changes in the brain. Also they try to use biochem to show that there "might" be damage. If you look closely at these negative studies, you will notice the use of the words should, could and might when describing the interaction between cannabis and the human brain. Strange eh! When looking for answers I find that going to the most knowledgeable source is the best choice. His name is Raphael Mechoulam. His team in Israel was the first to isolate the cannabinoid T.H.C. and what does this man say about marijuana. It is safe. It helps us to relax, eat, sleep and forget. Now don't think that forgetting is less important then remembering. We need a system that allows us to forget. If you walk thru a mall do you really want to remember the thousands of faces that you see. Our biological hard drive is called the hypacampus. It stores our memories and experiences. But like all hard drives, space is a finite resource. Which means it is possible to run out of that much needed space. Therefore the need to forget becomes really important. This also means that when you forget it changes the structure of the hypacampus. Amazing eh! I believe these structural changes in the brain that researchers are so worried about could be the bodies way of trimming the fat and streamlining the whole operation. Funny but the word fat is actually a great word for this comment. Your brain/grey matter is a modified fat. This is the matrix our neurons grow in and the reason we need those nice omega fats in our diet. A thought if I may. When we hit the 30's and older many people have had a pinched nerve. It can cause numb patches. Breathing problems. Motor and coordination difficulties. Also a host of other problems to numerous to list here. What if these changes they see are actually beneficial. The changes in the white matter that connects the two hemispheres of our brain and allows them to communicate back and forth. Might be getting streamlined to improve that communication. Like getting the pressure off of a pinched nerve. More white matter in such an enclosed space would mean more pressure being put on that white matter and as we all know pressure and nerves sometimes mix badly. I really wish they would get off this psycosis thing. If there was any validity to this at all. Then the world would have known about it thousands of years ago. But in all of the ancient medical writings there is no mention of it. Researchers today can't point to this or that and say see we told you cannabis was harmful. There is just to much supposition and bad interpretations of the data that has been released so far. What gets me is they are using these suppositions and bad interpretations to draft policies that we as a people have to abide by. It kinda sucks.
I am not an expert, nor have I done research on the material. The only thing that I can tell you is my own experience. I am an emergency room nurse, and in the last couple of years we have seen a noticeably increase in the teens with new onset psychosis. This are patients that do not have any previous psych history, no brain abnormality, not on medications, and the only drug in common that keeps coming up is THC. The physicians have been contributing this to the frequency and the strength . Just food for thought.