Hjorthøj C, et al. - Researchers assessed data from the combined nationwide Danish registers in order to determine if the risk of substance-induced psychosis increases in presence of infections, and if infections enhance the risk of converting from substance-induced psychosis to schizophrenia. In this study, they assessed data from 2,256,779 individuals; among these, incident substance-induced psychosis was recorded in 3,618 cases.  Analysis support the hypothesis that psychosis has an an immunological component. The risk of substance-induced psychosis raises in presence of any infection. Development of substance-induced psychosis was observed in strongest correlation with hepatitis. Link was observed of different types of infections with different types of substance-induced psychosis. Only hepatitis was identified as predictive of conversion to schizophrenia after substance-induced psychosis.