Prediction of recurrence and the influence of consecutive episodes on vulnerability: A 2-year prospective study in recurrent depression

Introduction
Depression is often a recurrent disease. Identifying risk factors for recurrence is essential. We aimed to identify factors predictive of recurrence and to examine whether previous depressive episodes, a well-known predictor of recurrence, influence vulnerability for subsequent depressive episodes in a sample of remitted patients with recurrent depression.

Methods
Recurrence was examined prospectively over 24 months in 172 euthymic patients with recurrent depression (DSM-IV). Baseline illness related characteristics, coping, and stress (life events and daily hassles) were examined as predictors of subsequent recurrence over 2 years.

Results
Risk factors for recurrence were a higher number of previous episodes, more residual depressive symptoms and psychopathology, and more daily hassles. Factors with both an increasing and decreasing pathogenic effect with increasing episode number were detected.

Discussion
We found some support for dynamic vulnerability models that propose a change of vulnerability with consecutive episodes. These results suggest that some factors that predict recurrence in patients with two previous episodes are not the same for patients with 5 episodes, or even 10 episodes. Researchers should not only differentiate between first onset and subsequent depression, but also consider both the increasing and decreasing pathogenic influence of lifetime history of depressive disorder. Preventive psychological interventions, should be considered in patients with multiple recurrences, focussing on residual symptomatology and specific coping styles.