[Drug use and dependence in schizophrenia]

Drug dependence is common in schizophrenia. Two main models explain this association: drugs precipitate psychosis in a vulnerable subject, and drugs use to self-medicate positive and negative symptoms and neuroleptics side effects. We investigated the prevalence of psychoactive substance use and dependence in schizophrenia and its association with the subtype of schizophrenia. The sample consisted of 56 outpatients with schizophrenia according to ICD-10, between 18 and 40 years, and a control group with 56 subjects with other different disorder. They were evaluated with Addiction Severity Index (ASI) and Positive And Negative Syndrome Scale (PANSS), sociodemographical, clinical and toxicological characteristics were evaluated too. Patients were classified in subtype negative, positive or mixed according to scoring in PANSS. Schizophrenics were reevaluates at six months of development. There were higher cocaine, alcohol, cannabis and nicotine use in schizophrenics. The patients with negative subtype of schizophrenia had more clinical severity, less scoring in alcohol and drugs subscales of ASI, lower prevalence of nicotine dependence and cocaine, amphetamines, cannabis and opioids use. Drugs use were associated with a poor compliance of treatment. Therefore, cannabis and cocaine dependence, regular alcohol use and tobacco use are more prevalent in schizophrenic than control group with other mental disorders. Negative subtype had lower drug use.