Procedural and declarative memory in obsessive-compulsive disorder

Abstract

Obsessive-compulsive disorder (OCD) has been associated with frontostriatal abnormality. This has led to the hypothesis that the disorder is characterized by abnormality of procedural memory. However, evidence for either procedural or declarative memory disturbance has been mixed, and few studies have directly assessed both of these forms of memory in the same patient group. In the present study, we assessed encoding and retrieval in declarative memory using the Rey Auditory Verbal Learning Test (RAVLT), and procedural memory using the Pursuit Rotor Task, in 27 adults with OCD and 29 matched healthy controls. Groups did not differ with respect to salient demographic characteristics or memory on the RAVLT. In contrast, patients with OCD performed significantly better than controls during the early, but not later trial blocks of the Pursuit Rotor Task. This pattern of results indicates intact encoding and retrieval in declarative memory, but abnormally enhanced procedural memory during the early course of learning in OCD. These findings may be consistent with striatal overactivation observed in neuroimaging studies of OCD, as well as the prominent role of the striatum during early stages of procedural memory.