Effect of Motivational Therapy on Schizophrenia With Cannabis Misuse

Schizophrenia is a severe mental illness with a lifetime morbidity risk close to 1 %, involving both genetic and environmental risk factors. Prospective studies have shown that heavy use of cannabis in adolescence moderately increases the risk of developing schizophrenia. Many data have also suggested that the co-occurrence of cannabis abuse in patients with schizophrenia has a deleterious impact on the clinical outcome of schizophrenia. Cannabis abuse by schizophrenic patients is a significant public health problem for which there is no empirically validated treatment. We are presently studying the efficiency of motivational therapy on cannabis consumption in patients with schizophrenia.