Presentation and Short-term Course of New Onset Cannabis Induced Psychotic Disorder in Males

Introduction Cannabis use has been associated with several psychosis outcomes including acute and persistent psychosis termed Cannabis Induced Psychotic Disorder (CIPD). The clinical and cognitive profile, course of CIPD, and the extent to which it is different from psychosis unrelated to cannabis exposure (PsyNoCan) is not clear. Methods The acute presentation and short-term (∼4 weeks) course of hospitalized male patients with new onset CIPD were compared prospectively to PsyNoCan using measures of psychosis, depression, mania, memory and other cognitive processes at admission, and after 4 weeks of inpatient hospitalization. A subsample of CIPD patients were followed up after 4-6 months of discharge. Cognitive test performance was benchmarked for comparison in healthy controls and individuals with Cannabis Use Disorder. Results Compared to PsyNoCan (n=53), CIPD (n=66) had a significantly lower severity of psychotic symptoms at admission but no differences in mood symptoms. After 4 weeks of hospitalization, the CIPD group had less psychosis. While both groups had significant cognitive deficits at baseline compared to healthy controls, cognitive test performance improved to a greater extent in CIPD. Amongst 16 CIPD cases with longitudinal follow-up data, 10 relapsed with psychosis within 6 months after resuming cannabis use. Conclusion CIPD in males has a distinct presentation and short-term course, characterized by less severe psychosis, and greater resolution of psychopathology and cognitive deficits relative to PsyNoCan. Relapse of cannabis use may predict poorer long-term outcomes with greater psychotic relapses. The longer-term course, prognosis and biology of CIPD, and its presentation in females needs further study.