title: Do cognitive and behavioral factors mediate the impact of depression on medical outcomes in people with coronary heart disease?
abstract: OBJECTIVE
  Depression is common in people with coronary heart disease (CHD) and predicts worse cardiac outcomes. Cognitive and behavioral mechanisms have been proposed to explain this association, although the mediating role of these mechanisms remains unclear. We conducted a prospective cohort study to investigate whether the impact of depression on subsequent impaired health-related quality of life (HRQoL) was mediated by cognitive and behavioral pathways.
  
  
  METHODS
  Demographic and medical characteristics, depression (Hospital Anxiety and Depression Scale), illness cognitions (Brief Illness Perceptions Questionnaire and Cardiac Anxiety Questionnaire), awareness of somatic symptoms (Symptom Checklist-90, revised version), and health behaviors were recorded from 255 primary care patients with CHD. The Short Form-36 was completed by 201 participants 6 months later.
  
  
  RESULTS
  Twenty-five participants (9.8%) were depressed at baseline. Short Form-36 Physical Component Score (PCS) was significantly lower in participants who were depressed (mean PCS score = 29.8 versus 38.0, P = .001). After controlling for demographic and medical variables, depression continued to be associated with subsequent PCS [B = -0.84 (0.20), P < .0005]. When cardiac anxiety, awareness of somatic symptoms, and negative illness perceptions were added to the regression model, depression no longer continued to make a significant independent contribution to the model [B = -0.3 (0.2), P = .16]. Maladaptive health behaviors did not fulfill criteria to mediate the relationship between depression and impaired health-related quality of life.
  
  
  CONCLUSIONS
  Findings indicate that the impact of depression on HRQoL could be mediated by cardiac anxiety, awareness of somatic symptoms, and negative illness perceptions, but not maladaptive health behaviors. Psychological interventions targeting these mediators have potential to improve HRQoL in people with CHD.
authors.affiliation: Psychiatry Research Group, School of Community Based Medicine, Manchester University, Manchester, UK. chris.dickens@manchester.ac.uk
authors.forename: Chris
authors.initials: C
authors.lastname: Dickens
authors.forename: Andrea
authors.initials: A
authors.lastname: Cherrington
authors.forename: Linda
authors.initials: L
authors.lastname: McGowan
mesh_terms: D003071:Cognition; D003327:Coronary Disease / Q000523:psychology*; D003863:Depression / Q000150:complications* / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life / Q000523:psychology*