The re-labelling of dysthymic disorder to persistent depressive disorder in DSM-5: old wine in new bottles?

Purpose of reviewDysthymic disorder and other chronic depressive disorders have recently been merged in DSM-5 into a persistent depressive disorder' category. As its introduction in DSM-III, the validity of dysthymic disorder has long been challenged, posing concerns regarding the validity of its successor - persistent depressive disorder. This review aims to present recent findings regarding the validity and utility of dysthymic disorder.Recent findingsSeveral recent studies raise questions regarding the validity of dysthymic disorder, namely, results indicating a significant overlap between dysthymic disorder and other mood and/or anxiety disorders, failure of such a diagnosis to predict illness outcome and the lack of any validation strategy identifying that it is a depressive entity or subtype.SummaryResearch findings indicate that dysthymic disorder is a heterogeneous diagnosis encompassing many different depressive (and anxiety or personality weighted) conditions, and without clear evidence of its validity as a diagnostic entity. As dysthymic disorder is a key component of DSM-defined persistent depressive disorder - the latter is at similar risk of providing a heterogeneous domain diagnosis, and thus limiting identification of specific causative factors and preferential treatment modality.