Altered Reward Processing in Obsessive-Compulsive Disorder: Insights From Active and Observational Learning.

Obsessive-compulsive disorder (OCD) has been associated with altered performance monitoring, reflected in enhanced amplitudes of the error-related negativity in the event-related potential. However, this is not specific to OCD, as overactive error processing is also evident in anxiety. Although similar neural mechanisms have been proposed for error and feedback processing, it remains unclear whether the processing of errors as indexed by external feedback, reflected in the feedback-related negativity (FRN), is altered in OCD. Likewise, it is currently unknown whether performance monitoring in OCD differs between learning from self-performed and observed outcomes. The present study compared OCD patients (n = 27) with healthy controls (HCs; n = 27) and patients with social anxiety disorder (SAD; n = 29) in an active and observational variant of a probabilistic feedback learning task while EEG was recorded. Compared to HCs, OCD patients showed generally impaired task performance across both active and observational learning, as well as more indecisive choice behavior. This was accompanied by generally more positive amplitudes of the FRN, with enhanced valence coding for active compared to observational learning, driven by more positive FRN amplitudes for wins. However, no differences were found for losses. Overall, these results suggest deficient reward-rather than punishment-processing in OCD. Similar performance monitoring alterations in OCD and SAD imply reliance on shared, disorder-general mechanisms. Possible candidates for these mechanisms, such as intolerance of uncertainty, pessimism, and depressiveness are discussed.