Clinical profile of cannabis-induced psychosis in comparison to schizophrenia

Abstract

BackgroundThe question whether substance-induced psychotic disorders can be differentiated from schizophrenia on the basis of clinical and psychological tests performance remains inconclusive. We hypothesize that cannabis-induced psychosis and schizophrenia have different cognitive, premorbid, and clinical features. ObjectiveThe main objective of this study was to investigate and describe clinical profile of cannabis-induced psychosis and to plot a comparative study between patients with cannabis-induced psychosis and schizophrenic with regard to cognitive abilities, different personality traits as well as phenomenological differences between both groups. Patients and methods This was a cross-sectional comparative study in which 60 patients were recruited; 30 patients with diagnosed cannabis-induced psychosis and 30 patients with diagnosed schizophrenia. The patients were selected from inpatient units and outpatient psychiatric clinics at the Institute of Psychiatry, Ain Shams University, over a period of 6 months. The recruited samples were assessed by a semistructured interview on the basis of the interview (questionnaire) sheet of the Institute of Psychiatry, Ain Shams University Hospital, and the diagnosis was made on the basis of ICD-10 symptom checklist. They were also assessed by the following scales: Wechsler Intelligence Scale, Minnesota Multiphasic Personality Inventory, and Positive and Negative Symptoms Scale. ResultsWe found that cannabis-induced psychosis patients have statistically significant better cognitive functioning in the object assembly, less lie and correction, more psychopathic deviation, more antisocial and borderline traits, and less negative and general psychopathology symptoms compared with schizophrenic patients. ConclusionResults from the present study support previous evidence that tasks of cognitive functions, personality assessment, and clinical evaluation distinguish cannabisinduced psychosis and schizophrenia even in the earliest stages of illness and that the two disorders can be differentiated on the basis of areas of selective deficit. However, the present results also support the hypothesis of a continuum of illness severity, in which significant deficits are evident in all diagnostic groups, but with different severity.