The role of neuropsychological testing in assessment of obsessive-compulsive disorder (OCD) is examined by review of 8 case reports and 14 patient series. Investigators generally agreed on localization of dysfunctional areas (e.g., prefrontal and frontal regions, limbic system, basal ganglia). They disagreed as to hemisphere and frontal lobe side impairment, involvement of other brain areas, pathophysiological connections, and impact of developmental phases and of concomitant cognitive and affective conditions. Conclusions about OCD pathogenesis are limited by test and sample variability. The authors outline an integrative approach based on sensorial and cognitive information disruptions that require activation of less specialized circuits. OCD may be syndromic, and subgroups may exist based on related but differentiable biochemical pathways.