Controversy Over the Diagnosis of ‘Cannabis-Induced Psychosis’
European Psychiatry January 1, 2009 M. Arendt
Among 535 people treated in Denmark for cannabis-induced psychosis and followed for at least three years, 44.5% later received a diagnosis of schizophrenia-spectrum disorders. New psychotic episodes of any type occurred in 77.2%, and 47.1% were diagnosed with schizophrenia-spectrum disorders more than a year after the initial cannabis-induced psychosis. Both those with cannabis-induced psychosis and those with schizophrenia had similarly elevated rates of schizophrenia and other psychiatric disorders in their first-degree relatives. Cannabis-induced psychosis may be an early sign of schizophrenia rather than a separate condition.