Experts warn against cannabis use during adolescence, pregnancy, and while driving

Experts recommend avoiding cannabis during adolescence and early adulthood, in people prone to or with mental health disorders, in pregnancy, and before and while driving, based on an in-depth evidence review published by The BMJ. However, they say cannabidiol (one active compound in cannabis) is effective in people with epilepsy, and cannabis-based medicines can help people with multiple sclerosis, chronic pain, inflammatory bowel disease, and in palliative care.

Their recommendations are based on an “umbrella review” of 101 meta-analyses on cannabis and health. Umbrella reviews synthesize previous meta-analyses and provide a high-level summary of evidence on a particular topic.

To address this, an international team of researchers set out to assess the credibility and certainty of over 500 associations reported between cannabis and health in 50 meta-analyses of observational studies and 51 meta-analyses of randomized controlled trials, pooling data from hundreds of individual studies.

Based on at least suggestive level evidence in observational studies and moderate certainty evidence in trials, the researchers found an increased risk of psychosis associated with cannabinoids in the general population.

Specifically, cannabis use was associated with psychosis in adolescents (when brain development is still taking place), and with psychosis relapse in people with a psychotic disorder.

Reference: Balancing risks and benefits of cannabis use: umbrella review of meta-analyses of randomized controlled trials and observational studies, The BMJ, DOI 10.1136/bmj-2022-072348