[The relationship between inflammatory markers, fatigue, and effort-based decision-making in patients at clinical...

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.

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.

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.

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.