To analyze social, demographic and clinical characteristics of patients with schizophrenia and comorbidity drug dependence.

Clinical interview with specially elaborated formalized card. Patients were diagnosed according to ICD-10 criteria. 182 patients were treated in St Petersburg state mental hospital № 3 in 2005-2010.

Alcohol, cannabis, and heroin tend to be the primary substances of abuse. According to the drug usage we form two groups. The first group (n = 105, 57,7%) consisted of patients who abuse alcohol only. The second group consisted of patients who use different types of drugs (n = 77, 42,3%). Both groups had high rates of unemployment, disability, length of stay in a psychiatric hospital.

Schizophrenia patients with multidrug dependence (2nd group) were younger than patients with alcohol dependence only (1st group). Middle age of patients of 2nd group was 31, 38 ± 0, 94 and middle age of patients of 1st group was 42, 45 ± 1,14. Patients of both group were unemployed 92 (87, 61%) and 62 (80,52%) respectively.

We identified statistically significant between-group differences in patients with paranoid schizophrenia. Patients of 1st group had paranoid schizophrenia higher 76 (72, 38%) than patients of 2nd group 39 (50, 65%). On the contrary, simple schizophrenia was diagnosed more often in patients of 2nd group 29, 87% and 14, 28% respectively.

Drug dependence disorders come before schizophrenia manifestation significantly more often (51,95%) than alcohol use disorders (AUD) (31,43%).

AUD occurred after schizophrenia manifestation (33, 33%) significantly more often than drug dependence disorders (12,9%).