Nonverbal memory dysfunction in obsessive-compulsive disorder patients with checking compulsions

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous disorder; nonetheless, most of the previous neuropsychological studies for assessing the involvement of memory dysfunction grouped together patients with different symptoms, thereby potentially accounting for the inconsistencies of results. The goals of this study were to compare the memory dysfunction of two main subtypes of OCD and to identify the type of memory dysfunction that is associated with the checking symptoms in OCD patients. The sample population comprised the cleaning-type OCD group (N=23), checking-type OCD group (N=24), and a control group of healthy volunteers (N=20). All the OCD patients were selected from the outpatient clinic. All the subjects underwent the Rey-Osterreith Complex Figure Test (RCFT) for the assessment of nonverbal memory function, the Hopkins Verbal Learning Test (HVLT) for verbal memory function, the Wechsler Adult Intelligence Scale-Revised (WAIS-R), and the Wisconsin Card Sorting Test (WCST). The immediate and delayed memory scores of RCFT were significantly lower in the checking-type OCD group; there were no significant differences in HVLT scores amongst the three groups. Our results indicate that the checking-type compulsion of OCD patients is associated with nonverbal memory deficits and not with verbal memory deficits.