Abstract # 3190 Stress-induced inflammation and dimensions of reward processing

Abstract

Dysregulated reward processing is a multifaceted and transdiagnostic feature of psychopathology. The psychobiological processes that contribute to reward dysregulation have not been delineated. The current study tested effects of stress-induced inflammation on three dimensions of reward: motivation, learning and sensitivity. Fifty-four healthy, female young adults (age 18–25) were randomized to an acute psychosocial laboratory stressor or a no-stress active control condition, and provided blood samples before, 60, 90 and 120 min after the stressor for assessment of plasma IL-6. Participants completed behavioral measures of reward-related learning (Probabilistic Reward Task) reward motivation (Effort Expenditure for Rewards Task) and reward sensitivity (emotional dot probe task) before and 90 min after the stressor. The stress group had significantly greater increases in circulating IL-6 from study entry to 120 min post-stressor than the control group, β = .25, p = .03. In mediation analyses, stress-induced inflammation predicted decreased sensitivity to social reward, as indicated by decreased positive attentional bias to happy faces (b = −19.70, p = .04). Stress-induced inflammation also increased reward motivation when the probability of winning monetary reward was low (b = .08, p = .01), and marginally increased sensitivity to monetary reward during reward learning (b = .06, p = .07). These findings indicate that stress-induced inflammation differentially alters dimensions of reward, potentially as a function of stimuli type (social vs. monetary), and contribute to a growing literature characterizing the nuanced effects of inflammation on behavior.