The Impact of Residual Symptoms on the Recurrence of Depression: A Population-based Study

Abstract

In clinical studies, remaining symptomatic following the resolution of a major depressive episode has been identified as one of the strongest risk factors for relapse and recurrence, however this association has not been explored within a general population setting. Using the National Population Health Survey, individuals who were previously depressed but not currently were followed up prospectively over twelve years (n = 560). The K6 Distress Scale was used to evaluate residual symptomatology. Using proportional hazards and binomial regression modelling, residual symptoms (19.7%) were found to be associated with early recurrence; symptomatic individuals were over three times likely to experience a recurrence within four years (RR 3.2; 95% CI: 2.0-5.1; p < 0.001), with the presence of even a single symptom conferring a substantial increase in recurrence risk (RR 3.1; 95% CI: 1.7-5.5; p < 0.001).