Differences in substance abuse patterns: multiple drug abuse alone versus schizophrenia with multiple drug abuse.

OBJECTIVE: To compare the lifetime consumption patterns of patients with schizophrenia and multiple substance abuse and multiple substance abusers without schizophrenia. METHOD: Two hundred and thirty in-patients of a specialized rehabilitation facility for young drug abusers were assessed with regard to their lifetime consumption patterns of 16 different classes of psychoactive drugs. While 110 patients had no diagnosis of a schizophrenic disorder, 120 patients had a comorbidity of multiple substance abuse and schizophrenia. RESULTS: Comorbid patients reported a higher lifetime consumption of hallucinogens, whereas multiple substance abusers without schizophrenia showed a higher lifetime consumption rate of cocaine. CONCLUSION: The differences found in lifetime consumption patterns between comorbid patients and substance abusers without psychotic disorder do not support the so-called self-medication hypothesis. Instead, the differences in lifetime consumption of certain drugs might be a result of lower social competence and standing in schizophrenic patients and lower ability to procure certain illicit drugs.