What is the meaning of treatment resistant/refractory major depression (TRD)?
Objective: To summarize and discuss the conceptual and operational definitions of treatment resistant/refractory depression (TRD) by systematically reviewing randomized controlled trials (RCTs) on its somatic treatment. Data sources: We searched the MEDLINE, Cochrane Library, PsyclNFO, and EMBASE for potentially relevant RCTs on the somatic treatment of TRD published from January 1996 to June 2006. Study selection: Studies were included if they: (a) enrolled patients at least 18 years old with a primary diagnosis of unipolar major depression considered resistant/refractory to treatment at baseline, (b) had a randomized design, (c) were published in peer-reviewed journals, and (d) were written in English. Trials that enrolled patients with secondary depression were excluded from our review. Finally, the bibliographies of relevant articles were hand-searched for additional references. In total, 233 full electronic references were retrieved, from which 47 meet the inclusion criteria. Data
