Biobehavioral Mechanisms of Emotion and HIV Disease: Exploring Potential Mediators of the Relation Between Trait Positive and Negative Affect and HIV Health Status

Abstract

BIOBEHAVIORAL MECHANISMS OF EMOTION AND HIV DISEASE: EXPLORING POTENTIAL MEDIATORS OF THE RELATION BETWEEN TRAIT POSITIVE AND NEGATIVE AFFECT AND HIV HEALTH STATUS By: Karen Elaine Stewart Master of Science Mississippi State University 2002 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University Virginia Commonwealth University, 2010. Major Director: Kirk Warren Brown, Ph.D. Assistant Professor Department of Psychology Considerable research supports an association between negative psychosocial functioning and adverse health outcomes. The biobehavioral model is well supported and posits that these effects occur via alterations in physiological response and health damaging behaviors. Evidence is accumulating about potential benefits of positive psychosocial functioning; however, less is known about the mechanisms of these effects. The broaden-and-build model of positive emotions holds that positive emotions can undo the physiological and behavioral restrictions associated with negative emotions and promote resource development. The present correlational study sought to explore whether cortisol, medication adherence, and health behaviors (smoking, alcohol use, physical activity, and nutrition) mediated relations between trait positive affect and negative affect and health status in persons living with HIV infection. A moderating role of trait positive affect on the relation between negative affect and mediating variables was also hypothesized, yet an unexpectedly high correlation between trait positive and negative affect precluded the evaluation of this hypothesis. HIV-infected participants (N = 53) collected salivary cortisol five times over the course of one day at home and completed interview the following day. Clinical staff provided HIV symptom ratings, and virologic and immunologic indicators were collected by chart review. Results showed that high trait positive affect was associated with lower total cortisol concentration, and total cortisol mediated the relation between trait positive affect and CD4+ percent. High trait negative affect was associated with poorer medication adherence, and percent adherence mediated the relation between trait negative affect and CD4+ percent and viral load. Mediation hypotheses for health behaviors were not confirmed. Trait positive affect was, however, associated with decreased alcohol intake, increased physical activity, and better nutrition habits. Because this study used crosssectional design, causation cannot be determined. However, findings provide preliminary evidence on mechanisms by which trait positive affect could be related to HIV disease markers, and findings support existing evidence on mechanisms of trait negative affect in HIV disease. Results also support use of the biobehavioral model and the broaden-and-build model of positive emotions as theoretical frameworks in studying the relation between psychosocial functioning and health outcomes in persons with HIV.