Cannabis May Be Tied to Increased Risk for Psychiatric Outcomes

TUESDAY, Sept. 5, 2023 (HealthDay News) -- Cannabis should be avoided in adolescence and early adulthood and by people at risk for mental disorders, according to a review published online Aug. 30 in The BMJ.

Marco Salmi, M.D., Ph.D., from University of Ottawa in Ontario, Canada, and colleagues conducted an umbrella review of meta-analyses to assess credibility and certainty of associations between cannabis, cannabinoids, and cannabis-based medicines and human health. A total of 101 systematic reviews with meta-analyses of observational studies and randomized controlled trials were included.

The researchers found that based on randomized controlled trials (high-to-moderate certainty), cannabis-based medicines increased adverse events related to the central nervous system (equivalent odds ratio, 2.84), psychological effects (3.07), and vision (3.00) in people with mixed conditions (Grading of Recommendations, Assessment, Development and Evaluations [GRADE], high) and improved nausea/vomit, pain, and spasticity, but increased psychiatric, gastrointestinal adverse events, and somnolence, among others (GRADE, moderate). In the general population, cannabis worsened positive psychotic symptoms (equivalent odds ratio, 5.21) and total psychiatric symptoms (7.49; GRADE, high), as well as negative psychotic symptoms and cognition (GRADE, moderate). In people with epilepsy, cannabidiol reduced seizures and improved quality of life, but conferred side effects. Cannabinoids improved sleep disruption in those with cancer, but carried a risk for gastrointestinal adverse events. Harmful effects were seen in pregnant women/neonatal outcomes and drivers. In healthy people, cannabinoids improved pain symptoms but impaired cognition. Cannabis-based medicines were effective in people with multiple sclerosis, chronic pain, and inflammatory bowel disease and in palliative medicine, but carried a risk for adverse events.

“Convincing or converging evidence supports avoidance of cannabis during adolescence and early adulthood, in people prone to or with mental health disorders, in pregnancy and before and while driving,” the authors write.

Several authors disclosed ties to the pharmaceutical industry.

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