Schizophrénie et addictions : les liaisons dangereuses

A majority of patients with schizophrenia are comorbid with addictions. Addictive comorbidities impact prognosis and outcome of the disease. They result in diagnostic and therapeutic challenges for caregivers since they are causing a considerable proportion of cases of non-response to treatment. These are the main causes of disability among adolescents and young adults patients in the world and their socio economic impact represents a growing challenge for all health systems. Double diagnosis are more frequent in homeless populations and represent a major risk factor of suicidal behavior. Consumption of psychoactive substances, Alcohol and illicit drugs contributes to excess mortality of schizophrenic patients to both natural and unnatural causes. Many factors have been identified to explain the reasons for this high comorbidity. Some genetic, social and economic factors are common between schizophrenia and addiction. Psychological and behavioral factors have mainly been studied in relation to the specific links between schizophrenia and cannabis. Two complementary hypotheses are argued, self-medication and damage hypothesis. Advances in brain imaging have shown that chronic cannabis use alters the morphology of the brain regions whith high concentration of cannabinoid receptors like hippocampus and amygdala. Though effects of cannabis may interact with other vulnerability factors of schizophrenia. The management of patients with schizophrenia and addiction requires clear diagnosis identification and integrated care with an efficient coordination between professionals. In regard of the impact on those who suffer, their entourages and the medical and economic impact of these disorders, measures on organizational care setting and promotion of research and evaluation are needed.