Psychological Medicine



Neuropsychological performance of OCD patients before and after treatment with fluoxetine: evidence for persistent cognitive deficits


M. M. A. NIELEN a1c1 and J. A. DEN BOER a1
a1 Department of Psychiatry, Section of Biological Psychiatry, School of Behavioural and Cognitive Neurosciences, University Hospital Groningen, Groningen, The Netherlands

Article author query
nielen m   [PubMed][Google Scholar] 
den boer j   [PubMed][Google Scholar] 

Abstract

Background. There is an ongoing debate about the nature of executive dysfunction that accompanies obsessive–compulsive disorder (OCD). One reason for this may be that state-related factors, such as use of medication or co-morbid symptoms, confound with task performance. This study tried to isolate trait- from state-dependent cognitive impairments by examining variability of cognition following treatment.

Method. Nineteen OCD patients were tested on the Cambridge Neuropsychological Test Automated Battery (CANTAB) before and after treatment with fluoxetine. Their pattern of performance was compared to the one observed in healthy volunteers (N=24).

Results. OCD patients displayed impairments in planning ability, spatial memory and motor speed that persisted after clinical improvement. With treatment, OCD performance diverged from that of controls on measures of focused attention and strategic ability. However, these effects were rather mild as they did not entail a significant deterioration of performance within the OCD sample.

Conclusions. Our data suggest that cognitive impairments in OCD are not secondary to symptoms and therefore form a trait feature of the disorder. The nature of the deficits refers to a chronic dysfunction of the dorsolateral–striatal circuit. The minor effects of treatment on task performance is in line with recent evidence that serotonin mediates cognitive functions of orbitofrontal cortex to a greater extent than those associated with dorsolateral prefrontal regions.


Correspondence:
c1 Dr M. M. A. Nielen, PET-Centre, VU Medical Centre, PO Box 7057, 1007 MB, Amsterdam, The Netherlands.


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