28 September 2022: Associations Between Neural Activity During Reward-Effort Decision-Making and Suicidal Ideation in a Recently Traumatized Sample

Courtney Forbes
Department of Psychology
University of California, Los Angeles (UCLA)

Background: Trauma exposure is associated with heightened risk for suicidality. Reward processing abnormalities have also been linked to suicidality; however, these relations have not been examined among individuals with recent trauma exposure. Research in this domain could inform understanding of specific risk factors for suicidality and highlight targets for intervention. Thus, the present study examined cross-sectional and longitudinal relations between self-report, behavioral, and neural reward processing and suicidal ideation (SI) in a sample with past 2-week trauma exposure.
Method: Participants were adults (N = 19, mean age = 31, 79% women, 53% racial/ethnic minority) recruited from hospital emergency departments. Within two weeks of the traumatic event, participants completed several self-report measures of reward processing as well as a behavioral fMRI task (the Staggered Effort-Based Decision-Making Task; Arulpragasam et al., 2018), in which they made decisions about whether to exert effort to obtain monetary rewards. Task-based neural activity was examined via whole-brain analyses, corrected for multiple comparisons, using the fixation point between trials as an implicit baseline. SI was assessed using the Quick Inventory of Depressive Symptomatology.
Results: No self-report or behavioral measure of reward processing was associated with SI, either cross-sectionally or longitudinally. Task-based activation in regions relevant to reward processing, specifically the insula and thalamus (rs = -.70 to -.53, ps ≤ .05), significantly correlated with baseline SI. Task-based activation in regions relevant to cognitive and regulatory processes (e.g., superior and inferior frontal gyri; paracingulate gyrus) also significantly correlated with baseline SI (rs = -.71 to -.46, ps < .05). Task-based activation did not significantly predict SI at 3-month follow-up.
Conclusions: In a recently traumatized sample, less activation in neural regions relevant to decision-making during a reward-effort task was associated with more frequent and intense SI cross-sectionally, but not longitudinally. If replicated, these results may indicate that impaired reward-effort decision-making following traumatic exposure contributes to risk for suicide. Relations between SI and task-based activation in regions related to cognitive and regulatory processes warrant further investigation.

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