Definition of treatment-resistant depression – Asia Pacific perspectives

Background: The lack of uniformity in the definition of treatment resistant depression (TRD) within the Asia-Pacific (APAC) region may have implications for patient management. We aimed to characterize the most commonly used TRD definition in selected APAC countries. Methods: A systematic literature review of TRD definitions in APAC countries was conducted in Medline and Embase (2010–2016) and conference proceedings (2014 and 2016). TRD guidelines (APAC, Europe regional, US, or international) were also searched. An expert-panel explored APAC nuances in TRD definitions to achieve consensus for a regional-level definition. Results: Ten guidelines and 89 studies qualified for study inclusion. Among the studies, variations were observed in definitions regarding: number of antidepressants failed (range: ≥1 to ≥3), classes of antidepressants (same or different; 59% did not specify class), duration of previous treatments (range: 4–12 weeks), dosage adequacy, and consideration of adherence (yes/no; 88% of studies did not consider adherence). No TRD-specific guidelines were identified. The emerging consensus from the literature review and panel discussion was that TRD is most commonly defined as failure to ≥2 antidepressant therapies given at adequate doses, for 6–8 weeks during a major depressive episode. Limitations: Few studies provided definitions of TRD used in daily clinical practice, and a limited number of countries were represented in the included studies and expert panel. Conclusion: Attaining consensus on TRD definition may promote accurate, and possibly early detection of patients with TRD to enable appropriate intervention that may impact patient outcomes and quality of life.