Scale matters: the need for a Bipolar Depression Rating Scale (BDRS)

Objective: To briefly review the clinical and biological distinctions between unipolar and bipolar depression critiquing in particular currently available depression rating scales and discuss the need for a new observer-rated scale tailored to bipolar depression. Method: Relevant literature pertaining to the symptomatic differences between bipolar disorder and unipolar disorder as well as their measurement using existing assessment scales was identified by computerized searches and reviews of scientific journals known to the authors. Results: Bipolar depression is distinct from unipolar depression in terms of phenomenology and clinical characteristics. These distinguishing features can be used to identify bipolarity in patients that present with recurrent depressive episodes. This is important because current self-report and observer-rated scales are optimized for unipolar depression, and hence limited in their ability to accurately assess bipolar depression. Conclusion: The development of a specific bipolar depression rating scale will improve the assessment of bipolar depression in both research and clinical settings and assist the development of better treatments and interventions.