Depression is common in people who have experienced recent Acute Coronary Syndrome (ACS), and predicts worse medical outcomes. Mechanisms underpinning the development of depression and its association with poor medical outcomes are unclear however. The aim of this study was to investigate the role of perseverative negative thinking (e.g. worry and rumination) in predicting depression in people with recent ACS.

Adults attending specialist inpatient and outpatient cardiology services who had recently experienced ACS were invited to participate in this observational prospective cohort study. Questionnaire assessments were completed within 6months of index ACS (baseline), then 2months and 6months later.

169 participants (131 male (78%), median age 68 (±16) years) completed baseline questionnaires, and 111 completed follow-ups. After controlling for the effects of key covariates, baseline rumination was a significant predictor of depression at 6months, accounting for 2% of the variance in depression. This association was partially mediated by poor problem-solving ability and lack of social support. Neither worry nor rumination at baseline were significant predictors of quality of life at 6months.

Rumination is a significant independent predictor of depression, and this association may be partially explained by deficits in problem-solving ability and reduced social support. Both rumination and problem solving may provide useful targets for the development of evidence-based interventions to reduce depression among people with coronary heart disease.