[Drug resistance in endogenous depression Part II. Refractoriness to antidepressants in affective disorders].

Among 67 patients admitted for the first time to the hospital drug resistance was evaluated in the further course of disease for at least 3 consecutive depressive phases. It was established that drug resistance occurs (usually as a single episode) in 28% of patients with endogenous depression and it concerns 10% of all depressive phases. The drug resistance is more frequent after the 45th year of life. The incidence of therapeutic failures is 3% during the first depressive phase and goes up in the consecutive phases. The occurrence of drug resistance in the past has no prognostic value for the next phase. There is a certain subgroup of patients, characterized by repetitive drug resistance during several phases. This phenomenon needs further evaluation.