[The relationship between inflammatory markers, fatigue, and effort-based decision-making in patients at clinical high risk for psychosis].

Abstract

Objective: To evaluate the associations between peripheral levels of inflammatory markers and willingness to exert effort in individuals at clinical high risk for psychosis (CHR-P) and a role of fatigue as a mediator of these associations.

Material and methods: Forty-nine young men admitted for a depressive episode, who met the criteria for CHR-P, had pre-treatment blood tests to determine levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukins IL-6, IL-8 and IL-10. After treatment and normalization of their condition, they completed the EEfRT task of willingness to exert physical effort to receive monetary reward and filled out the Fatigue Assessment Scale (FAS-10). The association between EEfRT scores, fatigue and inflammatory markers was assessed using regression analysis, controlling for residual clinical symptoms.

Results: Independent significant predictors of difficult task choices were the levels of CRP (b=-0.14; 95% CI: -0.30 - -0.07; p<0.001), IL-8 (b=-0.05; 95% CI: -0.09 - -0.002; p=0.043) and fatigue (b=0.07; 95% CI: 0.05 - 0.09; p<0.001). These indicators were not associated with the slope of the curve reflecting the dependence of the choice of difficult tasks on the probability and magnitude of reward.

Conclusion: In CHR-P, an increase in the levels of CRP and IL-8 before treatment may have prognostic significance regarding the persistence of motivational deficits in the form of a decrease in the willingness to exert efforts after relief of depressive symptoms. Fatigue is not a mediator of the identified relationship.