In the last ten years, there was an increasing interest for comorbidity between schizophrenia and substance abuse, including cannabis. Indeed, the cannabis use is significantly higher in patients with schizophrenia (15 to 40%) than in general population (16%).

The objective of this study was to determine demographic and clinical features of hospitalized schizophrenic patients with a history of cannabis abuse.

The aim of our study is to examine the relationship between cannabis use and the course of illness in schizophrenia.

This was a descriptive and a comparative study. Sixty Tunisian male with schizophrenia were divided in two groups: patients who abuse or are addicted to cannabis (cannabis+, N = 30) and patients who have never used this substance (cannabis-, N = 30).

In the cannabis (+) group, 33,4% of patients had a history of a long stay abroad and 50% had a criminal record. The difference between the two groups was statically significant (respectively p = 0,011 and p = 0,0001).

Antisocial personality disorder was significantly more prevalent in patients with cannabis (+) (p = 0.04), whereas subjects with a schizoid personality were essentially schizophrenic with no history of cannabis use (p = 0.026). Duration of untreated psychosis and number of hospitalizations were significantly associated with cannabis use (respectively p = 0,001 and p = 0,002).

Cannabis seems to complicate the evolution, and the management of schizophrenic illness. Identification and treatment of this addiction in a patient with schizophrenia is essential to ensure a better prognosis.