[Willingness to expend effort for rewards in individuals at clinical high-risk for psychosis: a relationship with the severity and stability of negative symptoms].

OBJECTIVE

To identify the deficit in willingness to expend effort and its association with negative symptoms in the high-risk for psychosis (CHR) group.

MATERIAL AND METHODS

The study included young men: 45 patients, who met CHR criteria and were treated for a depressive episode, and 15 controls. All subjects completed a modified version of the Effort Expenditure for Rewards Task (EEfRT). The CHR group was assessed with the SOPS, SANS and HDRS at the beginning and at the end of treatment. EEfRT was performed only at the end of treatment.

RESULTS

The CHR group was significantly less likely to choose high effort tasks across reward probability and magnitude levels compared with the control group (all 0.001). No significant correlations were found between the rate of selecting the high effort task and the negative syndrome domains of amotivation and diminished expression. The subgroups of CHR with stable and transient (i.e., with a reduction >50% during treatment) negative symptoms, which were identified by a cluster analysis, did not differ in the willingness to expend effort.

CONCLUSION

The study confirmed a decrease in the willingness to expend effort in the CHR group; however, this deficit was only weakly correlated with negative symptoms and persisted after the symptoms reduction during treatment, which requires future studies to investigate mechanisms underlying impaired effort expenditure for rewards in CHR.