The aim of the study was to investigate clinical and biochemical correlates of depression in the structure of schizophrenia to improve its diagnosis and differential diagnosis and to deepen understanding of mechanisms of schizophrenia development. Material and Methods. Forty-two inpatients at the stabilization stage of paranoid schizophrenia, aged 29.5±5.9 years, of whom 64.3% were women, were examined. The duration of the disease was 5.6±6.3 years. We used clinical and psychopathological methods, clinical scales (PANSS, SANS, BACS, Calgary Scale), catamnestic and clinic-laboratory methods (determination of brain-derived neurotrophic factor BDNF, proinflammatory cytokine interleukin-6, C-reactive protein). Results. At the stabilization stage, depression in patients with paranoid schizophrenia occurred in 19% of cases, more frequently in women. Female patients were more severely depressed, which was associated with an increased concentration of C-reactive protein, while negative symptoms predominated in male patients as compared to females. The presence of depression correlates with a lower severity of psychopathological, primarily positive symptoms and with a greater severity of neurocognitive deficit in schizophrenic patients. BDNF level directly correlates with the severity of positive and negative symptoms, and the level of interleukin 6 at the stage of remission formation does not differ from that in healthy individuals. C-reactive protein levels are associated with the characteristics of the course of schizophrenia.