Prevalence and correlates of the proposed DSM-5 diagnosis of Chronic Depressive Disorder

Abstract Context The draft proposal to add Chronic Depressive Disorder to DSM-5 will combine DSM-IV Dysthymic Disorder and Major Depressive Disorder, with chronic specifier, into a single diagnosis. Objective The objective of this study is to estimate the prevalence and correlates of the proposed DSM-5 diagnosis of Chronic Depressive Disorder using unit record data from the 2007 Australian National Survey of Mental Health and Wellbeing. Design Secondary analysis of a nationally representative household survey. Setting Urban and rural census tracts. Participants One individual between the ages of 16 and 85 years from 8841 households was interviewed for the survey. Main outcome measure Lifetime prevalence estimates for chronic and non-chronic depression were determined using data from the World Health Organization's Composite International Diagnostic Interview, version 3.0 (WMH-CIDI 3.0). Results Chronic depression of at least two years' duration had a lifetime prevalence of 4.6% (95% CI: 3.9–5.3%) and was found in 29.4% (95% CI: 25.6–33.3%) of individuals with a lifetime depressive disorder. Higher rates of psychiatric co-morbidity (OR = 1.42; 95% CI = 1.26–1.61), older age (OR = 1.04; 95% CI = 1.02–1.05), a younger age of onset (OR = 0.97; 95% CI = 0.95–0.98) and more frequent episodes of depression (OR = 1.75; 95% CI = 1.07–2.86) were found to be significant correlates of chronic depression. The first episode of depression for individuals with chronic depression often developed after the death of someone close (OR = 2.38; 95% CI 1.16–5.79). Conclusions Chronic depression is highly prevalent among community-residing persons and has a set of correlates that discriminate it from non-chronic depression. The distinction between chronic and non-chronic depression proposed for DSM-5, in the form of Chronic Depressive Disorder, seems to be warranted.