Review of dysthymia and persistent depressive disorder: history, correlates, and clinical implications.

Persistent depressive disorder is a chronic mood disorder that is common and often more disabling than episodic major depression. In DSM-5, the term subsumes several chronic depressive presentations, including dysthymia with or without superimposed major depressive episodes, chronic major depression, and recurrent major depression without recovery between episodes. Dysthymia can be difficult to detect in psychiatric and primary care settings until it intensifies in the form of a superimposed major depressive episode. Although information is scarce concerning the cause of persistent depressive disorder including dysthymia, the causation is likely to be multifactorial. In this narrative Review, we discuss current knowledge about the nosology and neurobiological basis of dysthymia and persistent depressive disorder, emphasising a dimensional perspective based on course for further research. We also review new developments in psychotherapy and pharmacotherapy for persistent depressive disorder, and propose a tailored, modular approach to accommodate its multifaceted nature.