Exploring expected reward and efficacy in enhancing cognitive control in patients with depression.

BACKGROUND: Depression is associated with impairments in cognitive control. Considering the lack of mechanistic models accounting for cognitive control deficits in depression, the expected value of control (EVC) theory offers a mechanistic view for allocating cognitive control emphasizing motivational components (efficacy, value). Efficacy refers to the possibility that an effort leads to a special outcome and reward refers to the value (amount) associated with the outcome. This study aimed to examine the role of the EVC in depression.

METHOD: This study used a within-between-subject design. Participants with depression ( n  = 36) and healthy controls ( n  = 31) completed a clinical diagnostic interview, the Beck Depression Inventory-II, the General Health Questionnaire-12, and a computer-based incentivized Stroop Color-Word Paradigm in which levels of efficacy (high vs. low) and the amount of rewards (high vs. low) were presented as cues before target stimuli.

RESULTS: We found significant interaction effects of group × efficacy and efficacy × reward in terms of reaction time in the Stroop Paradigm. Follow-up analyses indicated the Depressed group were significantly slower than Controls on high efficacy trials, but the two groups did not differ significantly on low efficacy trials. Additionally, on high efficacy trials, reward did not influence performance, but on low efficacy trials, high reward improved performance in both groups.

LIMITATION: Lack of neurological measures and eye tracking techniques.

CONCLUSION: Overall, our findings suggest that reward and efficacy may jointly improve cognitive control allocation and highlight the need for further research examining EVC theory as a mechanistic account of cognitive control deficits in depression.