Persistent Depression as a Novel Diagnostic Category: Results from the Menderes Depression Study.

ABSTRACT

INTRODUCTION: Persistent depressive disorder (PDD) introduced in the Diagnostic and Statistical Manual of Mental Disorders (DSM) 5 as a novel diagnostic category represents a consolidation of two separate DSM-IV categories, chronic major depressive disorder (MDD) and dysthymic disorder. The present study aims to investigate the frequency and clinical as well as socio-demographic correlates of PDD in comparison with those of episodic MDD among patients seeking treatment for depressive symptoms. METHODS: Participants were 140 depressive out-and in-patients under treatment at the psychiatry clinic of the Adnan Menderes University Research Hospital. Each patient was assessed by means of a structured clinical interview (SCID-I) and relevant psychometric instruments including the Hamilton Depression Inventory and Eskin Suicidal Behavior Inventory. RESULTS: Among the depressive patients, 61% fulfilled the criteria for PDD and 39% for episodic MDD. As compared with patients with episodic MDD, the PDD patients were older (d=.54), lower in educational attainment (d=.55), more likely to have comorbid generalized anxiety disorder (OR=3.7), and more prone to report symptoms of anxiety, hopelessness, pessimism, and somatic complaints. Nevertheless, the PDD patients displayed heterogeneous characteristics with respect to clinical severity and suicidal behavior. CONCLUSION: Our findings suggest that majority of depressive patients, including those fulfilling the criteria for MDD, have been suffering from a persistent ailment rather than an episodic disorder. Clinicians with a cross-sectional perspective are more likely to diagnose MDD, whereas those with a longitudinal perspective are more likely to identify PDD in the majority of depressive patients. The incorporation of both of these perspectives into DSM-5 in a complementary manner will possibly enhance our insight into depressive disorders and improve our treatment results.