In 79 patients with endogenous depressions (66 MDP and 13 circular schizophrenic patients) which received high doses of tricyclic antidepressants (amitriptyline in agitated forms and melipramine++ in inhibited ones) that remained ineffective for at least one month, hemosorption (HS; 39 patients) or ECT (40 patients) were randomly applied. The overall efficiency of HS and ECT was 53.8% and 60%, respectively. The efficiency of HS was substantially higher than that of ECT in the cases with dominant obsessive-phobic symptoms in depression. The reverse relation was observed in the cases with dominant anxious-delirious symptoms. In order to determine the predictors of the efficiency of the therapies, the stepwise discriminant analysis was used and the linear discriminant function equations were derived for HS and ECT involving 11 and 8 parameters, respectively. Correlation coefficients between predicted and de-facto therapeutic effects determined in an additional test group of 20 patients were 0.63 for HS and 0.88 for ECT. This is important in terms of directing a practitioner toward one or another technique with due respect for the individual differential therapeutic prediction of its result.