Adolescents who use cannabis could face a significantly higher risk of developing serious psychiatric disorders by young adulthood, according to a large new study published today in JAMA Health Forum. The longitudinal study followed 463,396 adolescents ages 13 to 17 through age 26 and found that past-year cannabis use during adolescence was associated with a significantly higher risk of incident psychotic (doubled), bipolar (doubled), depressive and anxiety disorders.
The study analyzed electronic health record data from routine pediatric visits between 2016 and 2023. Cannabis use preceded psychiatric diagnoses by an average of 1.7 to 2.3 years. The study’s longitudinal design strengthens evidence that adolescent cannabis exposure is a potential risk factor for developing mental illness.
Unlike many prior studies, the research examined any self-reported past-year cannabis use, with universal screening of teens during standard pediatric care, rather than focusing only on heavy use or cannabis use disorder.
The study also found that cannabis use was more common among adolescents enrolled in Medicaid and those living in more socioeconomically deprived neighborhoods, raising concerns that expanding cannabis commercialization could exacerbate existing mental health disparities.
It pretty much is, though I think this study is unusual in that it suggests that the effect may be independent of socioeconomic factors.
Though the authors do admit that there may be a bidirectional link at play, which is quite interesting, and relatively novel, off the top of my head. You’re at higher risk for schizophrenia or psychosis if you use marijuana, but you’re also more likely to use marijuana if you’re at higher risk for schizophrenia or psychosis. A lot of prior studies established the links individually, but didn’t combine them.
There are a few dotted throughout this thread, laying the blame on other things than the hasis.