Cannabis is the most widely produced and consumed illicit psychoactive substance worldwide.1 Following initiation, occasional cannabis use can progress to frequent use, abuse and dependence. About 1 in 10 occasional users becomes dependent, which is associated with physical, psychological, social and occupational consequences.2, 3 Despite the increasing use of cannabis for medicinal purposes,4 associations with adverse health effects have been reported.5, 6 These include increased risk for psychiatric outcomes, including psychosis, schizophrenia, schizotypal personality disorder and mania.7, 8 Early cannabis use appears to moderate relationship between polygenic risk scores for schizophrenia and brain maturation.9 In view of expanding medicalization and decriminalization, the potential consequences, and the debate surrounding the benefits versus adverse consequences associated with cannabis use,10 understanding the genetics of cannabis use should be a public health priority.11
