“Cannabis is the mostly commonly used drug of abuse by adolescents in the world,” wrote Gabriella Gobbi, M.D., Ph.D., of McGill University in Montreal, Canada, and colleagues. The authors systematically selected studies that assessed participants’ cannabis use when they were younger than 18 years old; adjusted for depression, anxiety, and/or suicidality at baseline; and tracked development of depression in young adulthood (age 18 to 32 years). The meta-analysis included seven studies for depression, three for anxiety, three for suicidal ideation, and three for suicide attempts, totaling some 23,000 participants.
The odds of developing depression in young adulthood was more than one-third higher among adolescents who used cannabis before age 18 (odds ratio [OR] = 1.4), compared with those who had not. The effect was more dramatic for suicidality: adolescents who used cannabis before age 18 were 50% more likely to think about suicide (pooled OR of 1.5) and more than three times more likely to have attempted suicide (pooled OR of 3.5) as young adults.
Younger users of cannabis, age 14 and 15, were at significantly higher risk of suicidal behaviors, according to the report, and girls seemed more susceptible than boys to develop adult depression if they smoked cannabis in adolescence, the researchers reported. “Two trajectory studies demonstrated that quitting cannabis by the end of adolescence did not protect people from some of the serious effects of the drug,” the authors added.
More than one-third of high school seniors reported using marijuana in 2018 (36%), with vaping of THC (the active ingredient in marijuana) rising at record levels, according to an annual National Institute on Drug Abuse-funded survey. At the same time, perceptions of harm and disapproval of marijuana use have trended down in recent years, with only 1 in 4 seniors agreeing that regular marijuana use poses a great risk—less than half of what it was 20 years ago. Ten states plus the District of Columbia have now legalized recreational use of marijuana for adults in 2019.
“These findings highlight the importance of initiatives aiming to educate teenagers on the risks associated with using cannabis and teach them skills to resist peer pressure,” Gobbi and colleagues concluded from their study. “Given the likelihood of a window of risk during adolescence when the deleterious effects of cannabis are most pronounced, the findings in this meta-analysis suggest that cannabis is a serious public health concern and there is an urgent need to implement better drug use prevention programs targeting the use of cannabis among adolescents and interventions aimed at educating adolescents to develop the skills to resist peer pressure on drug consumption.”
For more information, see the Psychiatric News article “Teen Vaping Surges While Use of Most Other Substances Flat” and the American Journal of Psychiatry article “A Population-Based Analysis of the Relationship Between Substance Use and Adolescent Cognitive Development.”
(Image: iStock/Stígur Már Karlsson/Heimsmyndir)