Cannabis-induced psychosis: a cross-sectional comparison with acute schizophrenia.

Cannabis-induced psychosis and acute schizophrenia show distinct demographic, premorbid, and clinical features. Among 61 patients (26 with cannabis-induced psychosis, 35 with acute schizophrenia), those with cannabis-induced psychosis were more often male, had more expansive mood and ideation, derealization or depersonalization, visual hallucinations, and sensorium disturbances. Premorbid schizoid personality traits were more common in acute schizophrenia, while antisocial personality traits were more frequent in cannabis-induced psychosis. The findings suggest that continuous heavy cannabis use can induce a psychotic disorder that is separate from acute schizophrenia, with both shared and differing characteristics.

Study at a glance

Abstract

The existence of cannabis-induced psychosis (CP) remains controversial, partly because of methodological problems. We hypothesize that acute schizophrenia (AS) and CP can have distinct demographic, premorbid and clinical features. We compared 26 patients with CP to 35 with AS, after their cannabis-consumption status was confirmed by repeated urine screens. Patients with CP were assessed after at least 1 week but not more than 1 month of abstinence. Symptoms were evaluated with the Present State Examination (PSE). In group CP, male gender, expansive mood and ideation, derealization/depersonalization, visual hallucinations, and disturbances of sensorium were more frequent than in group AS. Premorbid schizoid personality traits were more frequently associated to AS and antisocial personality traits to CP. The continuous heavy use of cannabis can induce a psychotic disorder distinct from AS. These two clinical entities share some features but they differ in others.