[Drug resistance in endogenous depression. Part I. Refractoriness to antidepressants in patients with depression admitted to a psychiatric clinic for the first time].

The efficacy of antidepressive treatment (mainly pharmacotherapy) was evaluated among 284 patients, admitted for the first time to the hospital with the diagnosis of endogenous depression. The first antidepressant therapy was found effective in 58% of the patients. Furthermore treatment with other antidepressants in the patients not responding to the initial therapy was successful in 57% of the cases. Drug resistance (defined as no therapeutical effect after 2 adequate courses of antidepressant treatment) was established in 7% of this sample. It was established that the drug resistance is more frequent after the 45th year of life. No relation between the drug resistance and sex, type of affective disorder, life events or somatic disorders were found.