Background: Patients with obsessive-compulsive disorder (OCD) have to repeat their actions before feeling satisfied that the action reached its intended goal. Learning theory predicts that this may be due to a failure in the processing of external feedback.
Method: We examined the performance of 29 OCD patients and 28 healthy volunteers on an associative learning task, in which initial learning is based solely on external feedback signals. Feedback valence was manipulated with monetary gains and losses.
Results: As predicted, OCD patients were impaired during initial, external feedback-driven learning but not during later learning stages. The emotional salience of the feedback modulated learning during the initial stage in patients and controls alike. During later learning stages, however, patients approached near-normal performance with rewarding feedback but continued to produce deficient learning with punishing feedback.
Conclusion: OCD patients have a fundamental impairment in updating behavior based on the external outcome of their actions, possibly mediated by faulty error signals in response selection processes.