Neuropsychological and Neurological Deficits in Obsessive-Compulsive Disorder: The Role of Comorbid Depression

Past research has found a high prevalence of neuropsychological deficits and neurological soft signs in patients with obsessive-compulsive disorder (OCD). A close relationship between OCD and depression has also been indicated in the literature. However, many aspects of this association remain unclear. In this study we compared neuropsychological functioning and neurological soft signs of 46 OCD patients who were off psychotropic medication (21 with significant depressive symptoms and 25 without) with 25 non-patient comparison subjects. The patients were matched to the comparison group with regard to age, sex, education, marital status and handedness. There were significant differences between OCD patients and the non-patient comparison group on neuropsychological functioning but not on neurological soft signs. As far as working memory concerns there was a significant difference between the OCD depressed and non-depressed groups. But we found no evidence that the neuropsychological functions such as cognitive flexibility, problem solving and spatial perception in OCD to be attributable to comorbid depression. The pattern of neuropsychological deficits in this sample of OCD patients is suggestive of orbito-frontal as well as dorsolateral prefrontal cortical dysfunction.