Frontiers in Psychiatry
July 21, 2026
Kenneth P. Finn, Robin M. Murray, Elizabeth Stuyt et al.
Cannabis use, especially high-potency products with THC concentrations above 10%, has been linked to rising psychosis cases from 1995 to 2010. Psychosis has multiple causes including genetics, childhood adversity, and drug use. This perspective argues that cannabis-associated violence deserves more attention, presenting high-profile media cases where THC was the only substance involved or cannabis use preceded psychosis and violence. Toxicology often fails to test for THC. The evolving evidence on cannabis, psychosis, and violence should inform medical screening, law enforcement, and policy.
World Journal of Biological Psychiatry
March 22, 2022
D. D’souza, M. Diforti, S. Ganesh et al.
Exposure to cannabis increases the risk for psychoses ranging from transient psychotic states to chronic recurrent psychosis. Greater dose and earlier age of exposure raise the risk. For some psychosis outcomes, evidence supports some causality criteria, but reverse causality and confounders cannot be ruled out. Cannabis is neither necessary nor sufficient to cause psychosis; it is likely one of multiple causal components. In those with established psychosis, cannabis negatively affects the illness course and expression. Emerging evidence suggests alterations in the endocannabinoid system in psychotic disorders. Delaying or eliminating cannabis exposure could potentially reduce psychosis rates, especially in high-risk individuals.
Translational Psychiatry
August 10, 2021
D. Quattrone, U. Reininghaus, A. Richards et al.
Genetic risk for schizophrenia and cannabis use each contribute to specific symptom patterns across psychotic disorders, not just diagnostic categories. Among 617 first-episode psychosis patients, higher schizophrenia polygenic risk scores were linked to more severe negative and positive symptoms, regardless of diagnosis. In 979 controls, the same genetic risk was associated with all dimensions of psychotic experiences. Daily or current cannabis use was tied to more positive symptoms in both patients and controls, beyond the effect of genetic risk. The findings support a dimensional view of psychosis, where genetic liability relates to symptom severity and cannabis use specifically increases positive symptoms.