We studied correlations between factors of inherent immunity and the effectiveness of therapy in patients with endogenous psychosis using the method of canonical correlations. There were strong significant (canonical R>0,8; p=0,02) positive correlations between the therapeutic effectiveness of neuroleptics (haloperidol and clozapine) and values of factors of inherent immunity in the group of 34 men with schizophrenia, aged from 16 to 34 years, with the first episode of psychosis. The effectiveness of treatment was assessed by the percentage reduction of total scores on the PANSS scale or scores on PANSS subscales (positive, negative and general psychopathology) at the beginning and the end (after 60 days) of the treatment. Initial parameters of factors of inherent immunity (levels of gamma-interferon production by T-lymphocytes, proportion of phagocytosing neutrophils and monocytes, and cytotoxic activity of lymphocytes - natural killers) contributed to 67,3%, or more than two thirds, of the variance of treatment effects. The contribution of inherent immunity factors was determined mainly by their similar effects on the reduction of positive and general psychopathological symptoms, with the minimal effect on the reduction of negative symptoms. The maximum correlation was found for weighting coefficients for inherent immunity factors estimated as 0,567 for the proportion of phagocytosing neutrophils and monocytes; 0,518 - for the levels of gamma-interferon production by T-lymphocytes and 0,334 - for cytotoxic activity of lymphocytes - natural killers. The authors suggest that the reduction of activity of the cell branch of inherent immunity develops before the disease manifestation. It creates conditions for the activation of latently persistent infections (the cytomegalovirus infection, in our case) in a patient's organism, with the formation of therapeutic resistance. The method described may be widely used in clinical and biological psychiatry and neurology.