Minutes

Schoeler, Tabea; Baldwin, Jessie R.; Martin, Ellen; Barkhuizen, Wikus; & Pingault, Jean-Baptiste. (2024). Assessing rates and predictors of cannabis-associated psychotic symptoms across observational, experimental and medical research. Nature Mental Health, 2, 865–876. https://doi.org/10.1038/s44220-024-00261-x

Does cannabis trigger psychotic symptoms? Who is most at risk? UK and Swiss scientists reviewed 162 studies comparing different kinds of research on cannabis-associated psychotic symptoms. 

The team pooled data from over 210,000 cannabis-exposed people across observational studies of recreational users, experimental trials administering THC (the active ingredient in cannabis) to healthy volunteers, and medicinal cannabis trials. The researchers checked how often psychotic symptoms happened and what raised the risk, e.g. THC dose, age, gender, mental health history, and genes. 

Results? In observational and experimental studies, 20% reported psychotic symptoms, compared with only about 2% in medicinal cannabis trials. Risk was higher with larger THC doses, younger age, female gender, and pre-existing vulnerabilities such as bipolar disorder, anxiety, depression, or family history of psychosis. Increased dopamine activity also predicted psychotic symptoms, while candidate genes did not. 

Thus, developing psychosis happens more in people who take more THC or already have mental health issues. As cannabis becomes more accessible and stronger in the U.S., doctors and users should pay attention to dose and personal risk factors. This matters most for young people, even those up to 35 years old, females, and those with mental health vulnerabilities. Beware; be smart. 

Written by Dan Peacock M.S.