[Stages of treatment resistance in depressive disorders, defined after somatotherapeutic methods].

This brief survey is not a systematic review of the literature on treatment-resistant depression (TRD). Rather, in the light of results of controlled clinical trials, proposals for assessment of TRD are made: First-degree treatment resistance implies nonresponse to standard antidepressive therapy (two successive adequate treatments with antidepressants, combined with induced-wakefulness therapy). Second-degree treatment resistance is defined by nonresponse to alternative treatment strategies (MAO inhibitors, lithium augmentation, electroconvulsive therapy, infusion therapy) that have proved to be effective in TRD both in clinical practice and in systematic investigations. In this therapeutic situation, the only option still open is to resort to previously ineffective therapy or to turn (as yet) inadequately established therapeutic strategies. Criteria for third-degree treatment resistance should not be based on nonresponse to specific further therapeutic trials but on the duration of the treatment (at least 2 years).