Kendler KS, et al. - Researchers followed individuals with a substance-induced psychotic disorder in national medical registries (N=7,606) for a mean of 84 months in order to describe the etiology of substance-induced psychotic disorder and its progression to schizophrenia. Observations suggest that in individuals at high familial risk for substance abuse and moderately elevated familial risk for psychosis substantial drug exposure may result in substance-induced psychotic disorder. Progression from substance-induced psychosis to schizophrenia could be predicted by familial risk for psychosis, but not substance abuse Schizophrenia following substance-induced psychosis is most likely not a syndrome mainly caused by drug exposure, but a drug-precipitated disorder in highly vulnerable individuals. Alcohol-induced psychosis had the lowest cumulative risk for progression to schizophrenia and cannabis-induced psychotic disorder had the highest.