Dysfunctions of Reward Motivation Adaptation in Patients With Schizophrenia

Diminished reward motivation in the wanting or liking dimension constitutes one of the core dysfunctions in patients with schizophrenia (SCZ). However, it remains unclear whether patients with SCZ would dynamically adapt their wanting or liking towards reward in response to a favourable effort-reward ratio and whether such adaptation correlates with their clinical symptoms or functional outcome. In this study, thirty patients with SCZ and 30 healthy controls (HC) were recruited to complete the reward motivation adaptation task (RMAT) based on mental arithmetic effort and manipulating effort-reward ratios. Clinical symptoms were assessed in the clinical group while pleasure experience and social functioning were assessed in all participants. We found that patients with SCZ exhibited less reward wanting and liking than HC in "effort = reward" and "effort < reward" conditions. Neither reward wanting nor liking in patients with SCZ adapted with effort-reward ratio as indicated by significantly smaller coefficients (βwanting and βliking) compared with HCs. Besides, SCZ patients' adaptation ability was positively correlated with social functioning in daily life. In conclusion, this study indicates that patients with SCZ not only exhibited reduced reward motivation in favourable conditions but also dysfunctions of reward motivation adaptation, and such deficits could explain poor functional outcome.