Teen Marijuana Use and Depression: Is there a Link?

By Hupu2 [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wik

There’s a popular argument against the legalization of marijuana because of evidence showing teens who use it may experience mood disorders later on in life. However, new research suggests the link doesn’t exist or at least may not be as pronounced as what was once feared.

Marijuana: Is it Really That Bad?

There have been a lot of smaller or medium sized studies performed and they appear to show an increased risk between heavy marijuana use during adolescence and mental health issues in adulthood. Previous research has often not considered data gathered from other studies over the years and it has often, not because of researcher mistakes, but because of the nature of certain studies, been limited as to what it can tell us about adolescent marijuana and the health of an individual in adulthood. Instead these studies have focused on the toxicity of cannabis and induced paranoia and other issues.

Research Studies

Research done by teams at the University of Pittsburg Medical Center and Rutgers University, has tried to start to fill in the gaps of knowledge.
The teams decided to look at the lives of 408 adolescent males and followed them into their adult lives. Data was gathered on the group via the Pittsburgh Youth Study, which started tracking 14-year old males in the 1980’s. It examined various things such as health, economic status and lifestyle choices these subjects made into adulthood.

The information cultivated involved surveying the participants every year or two. Then the group completed follow-up surveys conducted in 2009-2010, when they had reached 36-years of age. For the purpose of the latest research, study participants were separated into groups of four, based on their marijuana use, including low or non-users and early chronic users who started using it before or right as the study started.

Researchers found that those who used marijuana peaked at the age of 22 and then use declined as the subject got older. Based on previous studies, researchers expected to find that there would be an increase in health issues for chronic marijuana users as they became adults. However, surprisingly, there was no increase in the risks associated with physical or mental health issues distinguished in the data.

Lead researcher Jordan Bechtold, PhD, stated “What we found was a little surprising. There were no differences in any of the mental or physical health outcomes that we measured regardless of the amount or frequency of marijuana use during adolescence.”


There was no association found between marijuana use and mental health issues like depression or anxiety disorders. There is a common misconception of scientific evidence that has shown beyond a doubt that marijuana use among teens is linked to schizophrenia. While there were some early studies that suggested a possible link, more recent evidence appears to show no meaningful connection. There was also no evidence found during the most recent study either.

Furthermore, there was no association between an increased risk of respiratory problems, nor was there an increase in lung cancer, such as was previously suggested in past research.


The information provided on the PsyWeb.com is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her health professional. This information is solely for informational and educational purposes. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Neither the owners or employees of PsyWeb.com nor the author(s) of site content take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading this site. Always speak with your primary health care provider before engaging in any form of self treatment. Please see our Legal Statement for further information.

PsyWeb Poll

Are you currently taking or have you ever been prescribed anti-depressants?
Total votes: 3979