Pediatric Pearls: Cannabis and Depression in Adolescents

Answer: Cannabis use in adolescence is associated with an increased likelihood of developing depression and suicidal ideation.

Cannabis is the most widely used drug of abuse in the world. The effects of marijuana on the developing brain are still not a completely understood. However, growing evidence suggests that regular use leads to deleterious effects such as diminished scholastic achievement and earlier onset of psychosis. Little is known about the impact of cannabis use on mood and suicidality in young adulthood.

With this in mind, Gabriella Gobbi, MD, and colleagues conducted a systematic review and meta-analysis to determine the relationship between cannabis use and depression, anxiety, and suicidal behavior. Using 11 longitudinal and prospective studies including 23,317 participants younger than 18 years old, odds ratios (ORs) were determined for the development of depression, anxiety, suicidal ideation, and suicidal attempt in the setting of cannabis use. All studies reported ORs adjusted for prior history of depression and other confounding variables (such as alcohol use and sex).

The pooled OR regarding the development of depression during young adulthood among cannabis users compared with nonusers was 1.37 (95% CI, 1.16-1.62; I2=0%). Cannabis use was not associated with a significant development of anxiety with an OR of 1.18 (95% CI, 0.84-1.67; I2=42%). Results pooled from 3 studies that measured the association of cannabis use during adolescence with suicidal ideation resulted in an OR of 1.5 (95% CI, 1.11-2.03; I2=0%). The risk of suicide attempts was increased as well, with an OR of 3.46 (95% CI, 1.53-7.84, I2=61.3%).

A number of studies could not be included in the meta-analysis due to the nature of their reporting or the inclusion of the same cohort as another study. Most of these studies were found to have a positive correlation between adolescent cannabis use and the development of later depression, with chronic use presenting a higher risk of depression and anxiety.

The limitations of this type of study are evident here: Depression and depressive symptoms were detected using heterogeneous methods, and not every study adjusted for associated factors such as alcohol use. Quantity of use and the changing potency of marijuana were also not factored into this study.

This meta-analysis shows that cannabis use in adolescence is associated with an increased likelihood of developing depression and suicidal ideation. These findings illuminate the need for direct counseling and drug use prevention programs for adolescents. This crucial time of neurodevelopment must be protected from the deleterious effects of cannabis, especially in the setting of the current landscape. Families and care providers alike should align through thoughtful conversation on this topic.

Reference:
Gobbi G, Atkin T, Zytynski T, et al. Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood: a systematic review and meta-analysis [published online February 13, 2019]. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2018.4500.

Jessica L. Tomaszewski, MD, is a pediatrician in the Division of General Pediatrics/Primary Care in the Department of Pediatrics at Nemours duPont Pediatrics, Jessup Street, in Wilmington, DE.