ABSTRACT
Goal-directed and habitual systems orchestrate action control. In disorders of compulsivity, their interplay seems disrupted and actions persist despite being inappropriate and without relationship to the overall goal. We manipulated action–outcome contingency to test whether actions are goal-directed or habitual in obsessive-compulsive disorder (OCD), the prototypical disorder of compulsivity, in which prominent theories have suggested that dysfunctional beliefs underlie the necessity for compulsive actions.
OCD patients responded more than controls when an action was causally less related to obtaining an outcome, indicating excessive habitual responding. Patients showed intact explicit action–outcome knowledge but this was not translated normally into behavior; the relationship between causality judgment and responding was blunted. OCD patients’ actions were dissociated from explicit action-outcome knowledge, providing experimental support for the ego-dystonic nature of OCD and suggesting that habitual action is not sustained by dysfunctional belief.