There are no licensed pharmacological treatments for people who are at clinical high risk of developing psychosis. Although psychological interventions are well tolerated, they do not appear to reduce the risk of later transition to psychosis. Clinically high-risk people commonly experience low-grade anxiety and psychotic symptoms. Cannabidiol is a non-intoxicating substance present in cannabis that shows promise in terms of its antipsychotic and antianxiety potential. However, no fully powered randomised clinical trial has investigated the efficacy of cannabidiol as a treatment in people with clinical high risk. Further, the mechanisms that may underlie its beneficial effects remain unclear.
