Task Control in the Affordance Task as the Underlying Mechanism for the Imbalance Between the Goal-Directed and Habit Formation Systems in Obsessive–Compulsive Disorder

Background and Objectives: The habit formation model of obsessive–compulsive disorder (OCD) suggests that overreliance on stimulus-driven behaviors leads to repetitive compulsive rituals. Failure in task control, which leads to the stimulus-driven behaviors overriding the goal-driven system, could explain the mechanisms involved in this process. Methods: Patients with OCD and non-psychiatric controls completed the affordance task to understand the role of task control in maintaining compulsive behaviors. In the affordance task, participants are required to respond to a stimulus with one hand, while the stimulus on screen triggers a motor activation in either the congruent (same) or incongruent (other) hand. The affordance effect (accuracy for incongruent minus congruent trials) measures task control—the ability to suppress irrelevant, stimulus-driven, behaviors. Results: The affordance effect was larger in the OCD group, indicating a deficit in task control in those patients. Furthermore, a binary logistic regression analysis, using the affordances effect as a predictor and group as the outcome variable, revealed that the affordance effect correctly classified about 65% of the individuals with OCD compared to the non-psychiatric controls. The correlation between the affordance effect and OCD symptom-severity was not significant. Limitations: Handedness was assessed through self-report and OCD symptoms were mild–moderate. Conclusions: These findings strengthen the notion that task control deficits might account for the imbalance between the goal-directed and habit formation systems and that this deficit might be a risk factor for OCD but does not account for symptom-severity.