Effects of Obsessive-Compulsive Symptoms on Neuropsychological Test Performance: Complicating an Already Complicated Story

Abstract

Theoretical models of obsessive-compulsive disorder (OCD) implicate neurocognitive dysfunction, particularly deficits in nonverbal memory and executive functioning, in the pathogenesis of the disorder. The opposite hypothesis (poor performance in neuropsychological test as an epiphenomenon of OCD symptoms) has rarely been contemplated although checking behavior, obsessional doubt, lack of motivation, and slowness as well as preoccupation with touching objects may result in secondary test impairment and mimic manifestations of neural dysfunction. A total of 60 patients with OCD and 30 healthy controls were tested with a multi-functional neuropsychological battery. At the end of the testing participants were asked about their effort and the severity of OCD symptoms during task execution. Up to one fourth of the OCD patients affirmed OCD-related worries and motivational problems during task execution. Poor motivation and checking were significantly associated with enhanced objective performance deficits. Whereas the present study does not negate a role of neurocognitive deficits in the formation of OCD, in our view the reverse relationship should be contemplated as well. We advise researchers to pay closer attention to possible confounds that may mediate the relationship between OCD and neurocognition. Limitations of the study are discussed.

Keywords:

• Obsessive-compulsive disorder
• Neuropsychology
• Cognition
• Effort
• Motivation

Acknowledgment

This study was funded by the German Research Foundation (Mo 969/1-1).

Notes

¹The sample was a subgroup of the population reported in Moritz et al. (2005). We only considered patients with full data on the retrospective subjective performance questionnaire.

²As stated in the Introduction, we do not want to deny evidence suggesting brain dysfunctions in patients with OCD (Chamberlain et al., 2008; Maia et al., 2008; Menzies et al., 2008), especially in the orbito-frontal circuits, but the causal relationship to OCD (risk factor versus consequence or correlate) is not fully revealed, and such findings should not tempt researchers and clinicians to interpret task impairment as a direct manifestation of brain dysfunction.

³We are grateful to one reviewer for pointing this out.