Cannabis users genetically predisposed to schizophrenia may have higher risk for psychosis It has been long been known that cannabis users develop psychosis more often than non-users, but what is still not fully clear is whether cannabis actually causes psychosis and, if so, who is most at risk. A new study published in Translational Psychiatry by researchers at the Centre for Addiction and Mental Health (CAMH) and King's College London helps shed light on both questions. The research shows that while cannabis users had higher rates of psychotic experiences than non-users across the board, the difference was especially pronounced among those with high genetic predisposition to schizophrenia.