Marijuana & Anxiety

Teenagers who frequently smoked pot had higher anxiety later in life

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) The human brain is still in a state of rapid development during the teen years. Can using marijuana disrupt normal brain growth? A recent study followed a group of teens for 15 years to see how marijuana affected their mental health.

Study results showed that depression was not a factor, but that anxiety was likely.

"Marijuana may not be safe for teenage brains!"

Louisa Degenhardt, PhD, from the National Drug and Alcohol Research Centre at the University of New South Wales in Australia and George C. Patton, PhD, from the Centre for Adolescent Health at Royal Children’s Hospital and the University of Melbourne in Australia, investigated the link into the use of marijuana and anxiety in adolescents.

For the study, 1,943 teenagers between the ages of 14 and 17 in Australia were selected. Each of the participants was assessed six different times over the course of 15 years.

The group was assessed for depression and anxiety and asked about their marijuana usage.

Results showed that there was no link between marijuana use and depression later in life.

However, teens that smoked marijuana on a frequent basis, weekly and/or daily, were 2.3 times more likely to have an anxiety disorder later in life. Teens who were marijuana dependent were 2.5 times more likely to have anxiety during adolescence and later in life.

These results were consistent even if the person had stopped using marijuana for an extended period as long as 10 years.

Dr. Patton suggested that these results are due to brain development that happens during the teen years.

Dr. Patton said, “During the teen years the parts of the brain that are involved in managing emotions are still developing rapidly and it is highly possible that heavy cannabis use at this sensitive point could have long lasting effects.”

The authors did admit that anxiety could have existed before the use of marijuana began, which could predispose teenagers to use marijuana.

Further research would be necessary to fully understand the effects of marijuana during adolescents on mental health outcomes later in life.

This study was published in the July in the journal Addiction. Funding was provided by the Australian National Health and Medical Research Council and the Australian Government Department of Health and Ageing. No conflicts of interest were found.

Reviewed by: 
Review Date: 
August 12, 2012
Last Updated:
June 5, 2013