Challenges in reducing depression-related mortality in cardiac populations: cognition, emotion, fatigue or personality?
Depression is associated with increased morbidity and mortality in cardiac patients post-event; however treatment of psychological symptoms has failed to reduce cardiovascular risk. We explore depression and related constructs in terms of construct overlap and intervention potential. Certain depressive symptoms may be more important than others for increasing risk. Depressive cognitions may have lesser importance than somatic symptoms, but there is potential for designing interventions based on distorted illness perceptions. Somatic depressive symptoms and vital exhaustion are associated with increased risk. However, these symptoms may be more indicative of cardiovascular disease severity. A global tendency towards negative affectivity could account for the associations seen with negative affect states, with those of Type D personality demonstrating especially high levels of risk for morbidity/mortality. Positive emotion is associated with better outcomes, and could provide clues of how to intervene with negative emotion. Construct overlap and a dearth of theoretically based studies remain significant challenges. Future research needs to encompass all relevant variables to identify the key symptoms or symptom constellations that increase cardiovascular risk. A more sophisticated understanding of these issues can lead to more precise pinpointing of the 'cardiotoxic' aspects of psychological status, and ultimately to more refined interventions.