CORRESPONDENCE: LETTER TO THE EDITOR
Depression and Heart Failure: Why the Link Continues to Elude Us
Raj Persaud, FRCPysch*
* Bethlem Royal and Maudsley NHS Hospitals Trust, Monks Orchard Road, Beckenham, Kent BR3 3BX, United Kingdom (Email: r.persaud{at}iop.kcl.ac.uk).
Rutledge et al.’s (1) important and comprehensive review of depression in heart failure highlights the relative neglect in investigating the key parameters of this important association in the literature. The researchers remind us there remains as yet no investigation of the effects of a depression intervention on objective clinical outcomes such as survival or secondary cardiac events in a heart failure (HF) population.
However, although their useful review emphasized the biological connections between HF and depression, some of the emerging key issues on the link between depression and heart disease possibly emphasize more the social and perceptual impacts of effect.
For example, we know that depression has a negative impact on social networks, and it could be that it partially mediates its effects on cardiovascular systems via this variable. It is now a well-established finding that those individuals who are more socially integrated—for example, in long-term relationships or connected to communities or organizations—display lower risks of premature all-cause mortality than do those who are not so well integrated socially (2).
Piferi and Lawler (2) have recently demonstrated that social support not only had a positive impact on blood pressure but giving social support appears to represent a separate construct from receiving social support and may exert a uniquely positive effect on health. It might be that future studies on depression and HF, particularly intervention ones, would need to take this kind of social mediating variable into account, and be highly specific as to whether giving or receiving social support was measured.
Another key aspect of depression, which should be part of the future of research into depression and HF, is the specific impact of low mood on perception. For example, Ruo et al. (3) recently established that depression has a clinically significant effect on self-rated health among women with coronary disease, even after adjustment for clinical diagnoses. The magnitude of this impact of depression on self-rated health was similar to that of major cardiovascular events such as angina, myocardial infarction, angioplasty, HF, or coronary bypass surgery.
Whether depressed individuals are less compliant with treatments and medical advice, and whether they are unlikely to attend follow-up, are recalcitrant over exercise, losing weight, improving diet, and quitting smoking remain open questions. Thus, the precise pathway via how their depression impacts on their physical health continues to be a mystery.
This gap in our current knowledge probably accounts for the recent failure to demonstrate a significant impact on physical outcomes for treating depression following myocardial infarction (4).
Future research efforts into HF and depression, as well as heart disease and psychological states in general, need to measure more precisely the multiplicity of impacts of depression on an individual in order to ultimately produce effective treatments. Currently, the field seems intent on importing the way we treat standard depression in psychiatry into the way depression should be approached in cardiology. It is highly unlikely this is going to help heart patients in the long run, as this would probably neglect the unique and various specific impacts of depression in heart disease and vice versa.
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References
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- Rutledge T, Reis VA, Linke SE, Greenberg BH, Mills PJ. Depression in heart failure: a meta-analytic review of prevalence, intervention effects, and associations with clinical outcomes J Am Coll Cardiol 2006;48:1527-1537.[Abstract/Free Full Text]
- Piferi RL, Lawler KA. Social support and ambulatory blood pressure: an examination of both receiving and giving Int J Psychophysiol 2006;62:328-336.[CrossRef][ISI][Medline]
- Ruo B, Bertenthal D, Sen S, Bittner V, Ireland CC, Hlatky MA. Self-rated health among women with coronary disease: depression is as important as recent cardiovascular events Am Heart J 2006;152:e1-e7.[CrossRef][Medline]
- Berkman LF, Blumenthal J, Burg M, et al. Enhancing Recovery in Coronary Heart Disease Patients (ENRICHD) Investigators Effects of treating depression and low perceived social support on clinical events after myocardial infarction: the Enhancing Recovery in Coronary Heart Disease Patients (ENRICHD) randomized trial JAMA 2003;289:3106-3116.[Abstract/Free Full Text]
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