Cannabis use, Depression and Suicidal Thoughts in Teens
WRITTEN BY DESPINA BOLANIS, PHD STUDENT IN SCHOOL/APPLIED CHILD PSYCHOLOGY AT MCGILL UNIVERSITY, MONTREAL, QUEBEC. @DESPINAA (TWITTER)
A philosopher would ask themselves, which came first: the chicken or the egg? As a graduate student in psychology, I asked myself, which came first: cannabis use, depression or suicidal thoughts? Cannabis is the most widely used drug in North American teens and depression is also on the rise in this group. This is why our research team wanted to understand the timing between cannabis use, depression and suicidal thoughts. This knowledge could help guide treatment plans for teens presenting with these conditions simultaneously.
CANNABIS USE AND MENTAL HEALTH IN TEENAGERS
The teenage years are crucial to human development. In addition to teens’ growing independence (and often times, rebellion), these years are also marked with increased cannabis consumption, depression and suicidal thoughts. Given how common these mental health concerns are in teens, researchers have attempted to better understand their timing throughout the teenage years.
Studies have shown that cannabis use is a risk factor for depression and suicidal thoughts, while others have shown the opposite (commonly referred to as the “self-medication” hypothesis). These mixed findings make it difficult to understand the mechanisms of how cannabis use, depression and suicidal thoughts develop over time.
WHAT WERE THE GOALS OF THIS STUDY?
We wanted to test both hypotheses to see if 1) cannabis use is a risk factor for later depression and suicidal thoughts, or 2) if depression and suicidal thoughts are risk factors for later cannabis use.
HOW WAS THIS TESTED?
We used data from a large sample of teens who were born in Quebec in 1997/1998, and who completed questionnaires when they were 15, 17 and 20 years old. They provided information on their frequency of cannabis use, depression and suicidal thoughts.
Using specialized statistical techniques, we tested both of our hypotheses at the same time. This allowed us to answer the age-old question: which came first?
WHAT WERE THE RESULTS OF THIS STUDY?
We found that weekly cannabis use started at 15 years old for about 7% of the teens and increased to 12.6% by the time they were 20 years old. We also found that teens who used cannabis monthly were more likely to increase its use to weekly over time. These results suggest that cannabis use increases throughout the teenage years.
Our study did not find that cannabis use alone was a risk factor for suicidal thoughts. Rather, the combination of using other drugs, including cannabis, was a risk factor for suicidal thoughts. However, we cannot ignore that for some teens, using cannabis chronically is associated with negative outcomes. In a recent review that pooled the results from 11 studies, the authors found that teens who used cannabis weekly were more likely to have suicidal thoughts and depression when they were young adults.
We found that depression was a risk factor for weekly cannabis use, supporting the “self-medication” hypothesis. We highlighted that cannabis has the ability to temporarily alleviate negative mood states that exist prior to its use. Vulnerable teens may interpret this as therapeutic and they may mistakenly believe that cannabis helps them feel better. This is problematic because the underlying mood disturbance is still present and requires the attention of a mental health practitioner.
TAKE HOME MESSAGE
We can take away that cannabis use increases throughout the teenage years. Once this behaviour is initiated, using cannabis is likely to remain stable over time. Teens experiencing depressive symptoms were at heightened risk of using cannabis weekly over time. These findings highlight the importance of treating depressive symptoms in teens in an attempt to avoid them from starting to use cannabis as a coping mechanism.
MENTAL HEALTH RESOURCES FOR YOU AND YOUR TEEN:
Suicide Action Montreal: 1-866-277-3553
Kids Help Phone (Tel-jeunes): 1-800-263-2266
Text: 514-600-1002
Drugs: Help and Referral (DAR): 514-527-2626 (Montreal area)
1-800-265-2626 (everywhere in Quebec)
About the author
Despina Bolanis is a PhD student in School/Applied Child Psychology at McGill University, under the supervision of Dr. Marie-Claude Geoffroy (Canada Research Chair in Youth Suicide Prevention). She received her Master of Science in Psychiatry from McGill University in 2019.
Her PhD research focuses on documenting the effects of nature exposure on mental health, as there is a need for research on simple and free interventions aimed at improving mental health problems.
As a future psychologist, she intends on developing her skills in psycho-educational assessments and psychotherapy for youth experiencing depression, anxiety, and other related conditions.
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