Annual incidence of cannabis-induced psychosis, other substance-induced psychoses and dually diagnosed schizophrenia and cannabis use disorder in Denmark from 1994 to 2016
Psychological Medicine December 16, 2019 C. Hjorthøj, Maria Larsen, M. Starzer et al.
From 2006 to 2016, the incidence rate of cannabis-induced psychosis in Denmark rose from 2.8 to 6.1 per 100,000 person years. A corresponding increase occurred in dual diagnoses of schizophrenia with cannabis use disorder, while alcohol-induced psychosis decreased. Other substance-induced psychoses showed no clear trend. The rise in cannabis-induced psychosis parallels increases in both cannabis use and the THC content of cannabis, and changes in diagnostic practice do not appear to account for the increase.