(PS10-9) Effects of Posttraumatic Stress Symptoms and Thought Suppression on Anticipatory Reward Processing

Abstract Text: Reward system functioning is a core psychological construct comprising interrelated processes such as motivation, reinforcement learning, hedonic capacity, and reward responsiveness (Admon & Pizzagalli, 2015). Reward responsiveness has been divided into two temporally defined components with distinct effects on motivation: anticipatory reward responsiveness, (i.e., “wanting”; the pleasure derived from anticipation of reward) and consummatory reward responsiveness (i.e., “liking”; the pleasure resulting from engagement with rewarding stimuli; Berridge & Robinson, 1998). While posttraumatic stress disorder (PTSD) has been associated with alterations in multiple domains of reward system functioning (Fonzo, 2018; Nawijn et al., 2015), its specific impact on anticipatory reward responsiveness has yet to be fully explicated. Further, it is unclear how much of the observed link between PTSD symptoms and reward alteration is due either to the symptoms themselves or the strategies used to manage them. For example, thought suppression is a maladaptive emotion regulation strategy commonly linked to PTSD which may affect reward processing (Miethe et al., 2023). This study explored the unique influence of PTSD symptoms and thought suppression on a behavioral task assessing anticipatory reward responsiveness.

The Effort Expenditure for Rewards Task (EEfRT) captures expressions of effort-based anticipatory reward motivation across low, medium, and high probability levels (Treadway et al., 2009). In this study, 61 undergraduate students completed baseline questionnaires measuring PTSD symptoms (PTSD Checklist for DSM-5; PCL-5) and thought suppression (White Bear Suppression Inventory; WBSI), then completed the EEfRT.

Preliminary analysis revealed significant positive correlations between PCL-5 and EEfRT scores in low-probability trials, r(60) = .28, 𝑝 = .031, and between WBSI and low-probability EEfRT, r(60) = .39, 𝑝 = .002. PCL-5 and WBSI correlations with mid-probability, high-probability, and total EEfRT were not significant. A hierarchical regression explored the impact of WBSI after controlling for PCL-5. PCL-5 was entered in step 1, explaining a significant portion of the variance in low-probability EEfRT, 𝑅2 = .076, 𝐹(1,59) = 4.88, 𝑝 = .031. WBSI was entered in step 2, adding significantly to the model’s explanatory power, ∆𝑅2 = .076, 𝐹(2,58) = 5.23, 𝑝 = .008. Both PTSD and thought suppression were significantly predictive of low-probability EEfRT in this model.

To our knowledge, this is the first study to identify a unique relationship between PTSD symptoms and effort-based decision making specific to low reward probability. Results suggest that the failure to downregulate reward-based effort with decreasing likelihood of reward may represent a key clinical target in the treatment of PTSD symptoms and related reward system dysfunction. Regression findings further showed that both PTSD symptoms and thought suppression were significantly predictive of aberrant reward responsiveness, supporting the use of emotion regulation training to reduce thought suppression and improve reward-based motivation in this clinical population.