Will Legalization and Commercialization of Cannabis Use Increase the Incidence and Prevalence of Psychosis?
JAMA psychiatry April 8, 2020 R. Murray, W. Hall
Cannabis legalization and commercialization are increasing worldwide, with rising tetrahydrocannabinol potency linked to greater risks of dependence and psychosis. Dependence risk has risen from 9% to near 30% as potency increased. Daily use of high-potency cannabis raises psychosis risk up to 9-fold, comparable to the lung cancer risk from smoking 30 cigarettes daily. Evidence from prospective studies shows a causal relationship between cannabis use and later schizophrenia-like psychosis, not explained by confounding factors or reverse causation. Adolescents and those with a family history of psychosis are especially vulnerable. The cannabis industry's marketing and lobbying echo tactics used by the tobacco industry to downplay health harms.