Biobehavioral Correlates of Depression in Reaction to Mental and Physical Challenge

摘要

Depression is the most common mental disorder in the United States. Individuals with depression are at an increased risk of cardiovascular morbidity and mortality. However, little is known regarding the possible mechanisms to explain this relationship. One of the possible pathways includes exaggerated responsiveness to challenge in depressed individuals. The overarching hypothesis of this investigation is that depressed individuals display higher reactivity to mental and physical challenge than non-depressed controls. Specifically, it was examined whether elevated neurohormonal and negative mood responses to challenge tasks would result in elevated cardiovascular and inflammatory responsiveness. Reactivity to mental (mental arithmetic and anger recall) and physical challenge (exercise bout on treadmill) was assessed in 14 depressed and 16 non-depressed control participants. Neurohormonal (adrenocorticotropic hormone, cortisol, norepinephrine, and epinephrine), negative mood, cardiovascular (systolic blood pressure, diastolic blood pressure, and heart rate), and inflammatory (IL-6, TNF-a, and CRP) responses to mental challenge (anger recall and mental arithmetic( and physical challenge (treadmill exercise) tasks were assessed. Results indicated that depressed participants: 1) displayed higher reactivity of neurohormonal and negative mood measures, as well as increased cardiovascular and inflammatory responses during the challenge tasks; 2) neurohormonal and negative mood responsiveness were associated with cardiovascular and inflammatory reactivity; and 3) these relationships displayed variability across measures and challenge tasks. This study demonstrates that hyper-reactivity to challenge tasks can be documented among depressed individuals. Future research is needed to determine the consequences of hyperreactivity to the development of adverse cardiovascula.