Complex of clinical, EEG and neuroimmunological parameters was analyzed in patients with depressive-delusional conditions in order to clarify the role of neuroimmunity interaction in pathogenesis of mental disorders. Revealed correlations between values of EEG spectral power, immunological markers of neuroinflammation and neuroplasticity, and clinical assessments of patients emphasize the role of demyelination in pathogenesis and EEG pattern in depressive-delusional conditions.