Graduation Year

2010

Document Type

Thesis

Degree

M.A.

Degree Granting Department

Psychology

Major Professor

Jonathan Rottenberg, Ph.D.

Keywords

Major depressive disorder, Reward, Anhedonia, Response bias, Longitudinal

Abstract

A growing body of work links psychopathology to changes in hedonic capacity following stressors. This was the first experimental study of the effects of stress on hedonic capacity in an analog generalized anxiety disorder (GAD) sample (a high worry group). Specifically, we utilized an experimental manipulation of stress and a behavioral index of anhedonia to test the hypothesis that individuals with GAD, who are at higher risk for developing depression symptoms, exhibit greater stress-related deficits in hedonic capacity than do nonanxious controls. Further, this study assessed whether stress-induced hedonic deficits predicted future depression. Controls exhibited the expected reward learning pattern in the baseline condition, demonstrating intact hedonic responding, as well as the expected pattern of behavioral anhedonia under stress.

Contrary to predictions, worriers demonstrated intact hedonic capacity under stress. The stress effect in worriers was modulated by past depression diagnostic status; whereas worriers with no past depression demonstrated blunted baseline hedonic capacity and heightened hedonic capacity under stress, worriers with past depression demonstrated the normative response pattern. Blunted baseline response bias predicted higher future depression in both groups. We discuss the differential stress effects on behavioral hedonic capacity found as a function of worry, the role of past depression as a moderator of stress effects among worriers, and the need for future work to further explicate the mechanisms that may modulate reward response under stress.

Share

COinS