The authors present a narrative review from the diagnostic and nosologic viewpoints of mood disorders (bipolar and depressive ones) by revisiting the revision from the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, Text Revision to DSM-5, including the following: the separation of the bipolar and depressive sections; the addition of increased energy and continuation of symptoms to the hypo/manic criteria; the elimination of mixed episodes; the creation of new categories and specifiers ("other specified bipolar and related disorder", "disruptive mood dysregulation disorder", "with anxious distress", "with mixed features", "with peripartum onset"); the categorization of hypo/manic episodes during antidepressant treatment into bipolar disorder; the elimination of the "bereavement exclusion"; the ambiguous separation between bipolar I and II; the insufficient distinction between "other specified bipolar and related disorders" and major depressive disorder; the differentiation regarding borderline personality disorder; agitation; premenstrual dysphoric disorder; and society and psychiatry. Through this analysis, we point out both the achievements and limitations of DSM-5. In addition, to examine the future direction of psychiatry, we introduce our cohort study regarding maternal depression and an outline of the National Institute of Mental Health's Research Domain Criteria project in the US. Finally, we advocate the importance of elucidating etiopathogeneses by starting from or going beyond the DSM operational diagnostic system, which has shown great efficacy.
Keywords: Bipolar and related disorders; DSM-5; Depressive disorders; Diagnosis; Mood disorders; RDoC.