Acute stress selectively reduces reward sensitivity

Abstract

Stress may promote the onset of psychopathology by disrupting reward processing. However, the extent to which stress impairs reward processing, rather than incentive processing more generally, is unclear. To evaluate the specificity of stress-induced reward processing disruption, 100 psychiatrically healthy females were administered a probabilistic stimulus selection task (PSST) that enabled comparison of sensitivity to reward-driven (Go) and punishment-driven (NoGo) learning under either "no stress" or "stress" (threat-of-shock) conditions. Cortisol samples and self-report measures were collected. Contrary to hypotheses, the groups did not differ significantly in task performance or cortisol reactivity. However, further analyses focusing only on individuals under "stress" who were high responders with regard to both cortisol reactivity and self-reported negative affect revealed reduced reward sensitivity relative to individuals tested in the "no stress" condition; importantly, these deficits were reward-specific. Overall, findings provide preliminary evidence that stress-reactive individuals show diminished sensitivity to reward, but not punishment, under stress. While such results highlight the possibility that stress-induced anhedonia might be an important mechanism linking stress to affective disorders, future studies are necessary to confirm this conjecture.

Keywords: affect-cognition interactions; anhedonia; cortisol; depression; emotion; punishment; reward; stress.

Figure 1

Schematic representation of the session timeline. CORT, collection of saliva sample to measure cortisol level; MSQ, mood state questionnaires (“in-the-moment” state self-report questionnaires); PSST, Probabilistic Stimulus Selection Task.

Figure 2

(A) Schematic representation of the training phase of the Probabilistic Stimulus Selection Task, which was performed under stress or no stress conditions. In the no-stress condition, every time a red border flashed, participants were instructed to press a foot pedal to indicate they were attending to the task. In the two stress conditions, participants were told that the border flashing red indicated a shock might occur in the ensuing 15–30 s. In the controllable stress condition, participants were further instructed that they could reduce (though not fully eliminate) the likelihood of the shock if they pressed the foot pedal when they saw the red border cue. In contrast, participants in the “uncontrollable stress” condition were instructed to press the foot pedal to indicate they were attending to the task. (B) Schematic representation of the test phase of the Probabilistic Stimulus Selection Task. No stress was presented during this phase.

Figure 3

Affective ratings in the no-stress (n = 27) and stress-reactive (n = 18) groups at baseline and during the PSST. (A) State Trait Anxiety Inventory (STAI) scores; and (B) Negative Affect score on the Positive and Negative Affect Schedule (PANAS). For both scales, the state version was used.

Figure 4

Performance on “Choose A” and “Avoid B” trials during the PSST test phase in the no-stress (n = 27) and stress-reactive (n = 18) groups. (A) Accuracy; (B) Reaction Time (in ms).