In Case You Haven't Heard…

Abstract

You have heard all the stories about cannabis and psychosis — mostly in the “which came first” category. Now a study has linked them in a perfect loop, finding that a genetic predisposition to schizophrenia may increase the risk of psychosis from cannabis use. The study, published in Translational Psychiatry by researchers from the Centre for Addiction and Mental Health (CAMH) and King's College London, found that while cannabis users had higher rates of psychotic experiences than non‐users, the difference was pronounced among those with a genetic predisposition to schizophrenia. “These results are significant because they're the first evidence we've seen that people genetically prone to psychosis might be disproportionately affected by cannabis,” said lead author Dr. Michael Wainberg, a scientist at the Krembil Centre for Neuroinformatics at CAMH. “And because genetic risk scoring is still in its early days, the true influence of genetics on the cannabis‐psychosis relationship may be even greater than what we found here.” Overall, people who had used cannabis were 50% more likely to report psychotic experiences than people who had not. However, among the fifth of participants with the highest genetic risk scores for schizophrenia, it was 60%, and among the fifth with the lowest scores, it was only 40%.