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Commentary: Marijuana Use and Adolescents: What Clinicians Need to Know


As marijuana use among teenagers increases and its perceived danger among this age group decreases, clinicians need to know the latest science about the harmful effects of the drug on the adolescent brain, according to a researcher at the University of Colorado, Denver.

Paula Riggs, PhD, Professor of Psychiatry, notes the most recent Monitoring the Future Survey shows a significant increase in marijuana use, including daily marijuana use among U. S. high school students and a decrease in perceived risk of use. “There are a number of indicators, including the increasing number of states that have passed ‘medical marijuana’ legislation, and that society as a whole tends to view marijuana as a relatively benign, recreational drug. However, scientific research does not support this.”

A growing body of research shows that adolescent marijuana use can be detrimental to the brain development and may produce long-lasting neurocognitive deficits and increased risk of mental health problems including psychosis, said Dr. Riggs, who spoke about this topic at the recent California Society of Addiction Medicine meeting.

Marijuana is the most commonly used illicit drug in the United States. Although some have questioned whether marijuana is an addictive drug, scientific research shows that one in 10 people overall, and one in six adolescents, who use marijuana develop dependence or addiction, Dr. Riggs says. Research shows that marijuana can cause structural damage, neuronal loss and impair brain function on a number of levels, from basic motor coordination to more complex tasks, such as the ability to plan, organize, solve problems, remember, make decisions and control behavior and emotions.

Dr. Riggs also cited recent studies indicating that adolescents may be more vulnerable to addiction, in part due to rapid brain development. “Emerging research suggests that individuals who start using marijuana during their teenage years may have longer-lasting cognitive impairments in executive functioning than those who start later,” she says. “Animal studies also suggest that exposure to marijuana during adolescence compared to adulthood may increase the vulnerability or risk of developing addiction to other substances of abuse such as cocaine and methamphetamine.”

She adds, “It is important for pediatricians, psychiatrists and other mental health clinicians to be aware of current research because they are on the front line to identify teens when they first start to experiment. They need to be able to effectively screen adolescents for marijuana use, and be armed with the scientific facts to educate teens and families about associated risks.”

10 Responses to this article

  1. Stephanie / November 17, 2011 at 4:52 pm

    What will it be legalized as?

  2. Kevin C / November 17, 2011 at 10:55 am

    FYI – If it is the same Dr. Paula Riggs, I believe she is a Doctor of Medicine (M.D.), not a Ph.D. as stated in the article. Being a mental health professional who reads many journal articles from varying sources, I can unequivocally say that research findings accepted for publication by journals in the medical field often do not follow the same rigors that psychologists set for their field. (No, I am not a psychologist.) I would not venture to say that the evidence is culled or thin, but I would want to see the basis of conclusions before accepting what is being presented in the article above vis-a-vis Dr. Riggs’s remarks. As for legalization, we in the United States need to learn from history. We have but to look at the failings of Prohibition to realize that you cannot control that which you do regulate. Marijuana is already underground and yet is used by upwards of 6 million people in the United States. It is simply not cost-effective or realistic to prosecute and house in our prisons for a realitively minor crime such as possession and use. The tobacco companies are well positioned to turn this into a cash crop and our country sorely needs the revenue that legalization could produce. And, just as we can regulate the sale of alcohol to minors, yes, we should keep marijuana out of the hands of and away from the still developing brains of adolescents. We cannot get a grip on the problems with marijuana until we get a grip on reality and deal with it rather than deny it.

  3. Fred C / November 16, 2011 at 11:29 am

    I am a professional counselor whose main experience is in substance abuse. You are right when you say that most bad press about MJ is overblown. A study that I read about in this journal concluded that the scizophrenia connection was bogus, However, no one covered the main danger of marijuana which is apathy, I smoked MJ for a few years over 40 years ago, yes the hippie era, and I tell my classes all it did for me was make me fat, lazy and stupid. I had to quit it to get myself back to college and earn a degree, or I would probably be in a homeless shelter now. The worst “gateway” drug is tobacco. most smokers learned early that they could control their mood by ingesting a chemical, and that can lead to a lifetime of dependence. To the mother who sat with her kid in the ER after smoking pot, it is possible that your son is allergic to marijuana, but it is more likely that he got some that was ‘dusted’ or soaked in another chemical. It also could have been a synthetic like spice which is many times more poisonous than MJ. Don’t tell him this though, it is better if he thinks he just cannot smoke pot at all. I believe in MJ for medical reasons but not for general legalization. And especially not during brain-developing, teen years.

  4. Ken Wolski / November 15, 2011 at 9:46 am

    Exaggeration of the dangers of marijuana does a great disservice to drug education. According to a well respected reference for health care workers, the Merck Manual, “Critics of marijuana cite much scientific data regarding adverse effects, but most of the claims regarding severe biologic impact are unsubstantiated. Findings are sparse even among relatively heavy users and in areas intensively investigated…Even daily smokers do not develop obstructive airway disease. Lung cancer has not been reported in people who smoke only marijuana…Any drug that causes euphoria and diminishes anxiety can cause dependence, and marijuana is no exception. However, heavy use and reports of inability to stop are unusual. Marijuana is most commonly used episodically without evidence of social or psychologic dysfunction. A mild withdrawal syndrome may occur when the drug is stopped…” Marijuana is about as addictive as caffeine.

  5. Jean / November 14, 2011 at 10:13 pm

    As a parent whose child became psychotic from marijuana use, I would have taken more precautions had I known of this risk. However, from my experience a child can become addicted even before parents learn of his/her use, which makes it much harder to control the use because the child can crave the drug to such an extent that he/she will run away from home and/or become completely out of control. The Dr.’s warning is completely accurate.

  6. Marcia / November 12, 2011 at 1:15 pm

    Yet another reason why marijuana SHOULD BE LEGALIZED. If you were to actually pay attention to what the proponents of legalization are saying, legalization would regulate use of the product, as is the case with tobacco and alcohol, making it much more difficult for young people to obtain it. I doubt you will find many people who are advocates of ending drug prohibition that think everyone and anyone should have access, which of course is the case now, thanks to drug prohibition and your Big Pharma sponsored drug pushers in too many medical clinics and the local street corner.

  7. Sandra / November 12, 2011 at 12:01 pm

    This seems like very thin evidence, culled from sources that are clearly biased in favour of finding every possible problem associated with patients using marijuana, and attributing them to the drug. I did not purchase the articles from the Journals they were published in, but I would have had more confidence in meta-analyses published in peer-reviewed journals of other disciplines–perhaps that is where significant studies came from. I don’t impute bad motives to anyone involved, but studies from people who treat addiction are from a different viewpoint than those from a neurology study.

    The study about psychosis concluded that people who would have developed schizophrenic-type diseases at around 20-22 years of age developed them at 18-20 if they used drugs including marijuana. They speculated this might happen in patients who were not predisposed to psychotic disorders, but this has never been proven for any drug. Chemical psychosis is reversible. Brain damage from alcohol or other toxicity or oxygen deprivation does not lead to psychosis, it leads to lack of function.

  8. Avatar of MG
    MG / November 14, 2011 at 10:42 pm

    I’m fascinated by the concentrated efforts of the pro-pot crowd in scouring the Internet to find stories like this and post negative, pro-pot comments. With the number of teenagers rapidly increasing the use of this substance, it is, at the very least, ridiculously irresponsible to make the comments posted by “Marcia” and “Sandra”. As one of the parents who recently spent the night in the emergency room after my young son reacted after being given pot at school, I am appalled by your comments giving young people another excuse to ruin their lives.

  9. Avatar of Jim
    Jim / November 16, 2011 at 9:45 am

    I agree with MG. The other thing I find interesting is those same people have no studies or research that supports their side. I used to engage in what I thought was going to be stimulating conversation with pro-pot people. With one exception they really just wanted to argue. That exception tried to quote studies that violate the who, what, when, where, and why of good research. Some of the information cited here has been around since the 80s at least. The 90s to current brought a large amount of “good” research (see above).

  10. Kevin C / November 17, 2011 at 10:58 am

    We have but to look at the failings of Prohibition to realize that you cannot control that which you do not regulate.

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