The aim of the study was to investigate clinical-psychopathological and pathopsychological peculiarities of suicidal behavior in patients with endogenous and exogenous depressions in order to develop principles of differential therapy and prevention for these patients.

Depressed patients with suicidal behavior (120 persons; main group) and without one (30 persons; control group) were examined with clinical-psychopathological, psychodiagnostic and psychometric methods.

Combined psychogenias prevailed among factors of psychic traumatization (loneliness - 44.2%, job dissatisfaction - 28.3%, worsening of well-being - 24.2%, and loss of job - 23.3%).

In a clinical picture there was predominance of anxious (50.8%) and somatic-autonomous (46.6%) variants of the syndrome, less often asthenic (24.2%) and melancholic (22.5%), and rarely obsessive (5.8%) and tearful (5.0%) variants were pointed out. In the patient of the control group asthenic (76.6%) and adynamic (56.6%) variants of depressive syndrome were prevailed. Patients of the main group with endogenous depressions more often had anxious (70.0%), melancholic (45.0%), and senesthopathic (31.6%) variants; patients with exogenous depressions had somatic-autonomous (65.0%) and asthenic (43.3%) variants.

A differential system for crisis therapy and prevention of suicidal behavior in depressions was developed. It included pharmacotherapy and psychotherapy (in three stages: rational psychotherapy for a crisis support, group psychotherapy for a crisis intervention, cognitive-behavioral therapy for prevention). This system had a higher therapeutic efficacy as compared with methods used traditionally (recovery - 59.5% vs. 35.1% (p< 0.05); a significant amelioration - 23.8% vs. 21.6%; amelioration - 7.1% vs. 16.2%; without dynamics - 9.5% vs. 18.9%; aggravation - 0% vs. 8.1%).