Depression, acute coronary syndrome, psychological theory, life events, personality, just world beliefs
Depression is associated with increased cardiovascular risk in patients with acute coronary syndrome (ACS), but some argue that elevated depression is actually a marker of cardiovascular disease severity. Therefore, disease indices should be better predictors of depression than established theoretical causes of depression (interpersonal life events, reinforcing events, cognitive distortions, type D personality). However, little theory-based research has been conducted in this area. In a cross-sectional design, hospitalised ACS patients (n=336) completed questionnaires assessing depressive symptoms and vulnerabilities. Nested logistic regression assessed the relative contribution of demographic or vulnerability factors, or disease indices or vulnerabilities to depression. In multivariate analysis, all vulnerabilities were independent significant predictors of depression. Demographic variables accounted for <1% of the variance of depression status, with vulnerabilities accounting for significantly more (pseudo R2=.16, ÷2(change)=150.9, df=4, p<0.001). Disease indices accounted for 7% of the variance in depressive status (pseudo R2=.07, ÷2=137.9, p<0.001). However, adding the vulnerabilities increased the overall variance explained to 22% (pseudo R2=.22, ÷2=58.6, df=4, p<0.001). Theoretical vulnerabilities predicted depression status better than did either demographic or disease indices. The presence of these proximal causes of depression suggests that depression in ACS patients is not simply a result of cardiovascular disease severity.
Doyle F, McGee H, Conroy R, Delaney M. What predicts depression in cardiac patients: Sociodemographic factors, disease severity or theoretical vulnerabilities? Psychology & Health. 2011;26(5):619-34.