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


METHODS
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.
Nielen
M M A
MM
Department of Psychiatry, Section of Biological Psychiatry, School of Behavioural and Cognitive Neurosciences, University Hospital Groningen, Groningen, The Netherlands.
Den Boer
J A
JA
D000293:Adolescent; D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use*; D003071:Cognition / Q000187:drug effects*; D005260:Female; D005473:Fluoxetine / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000188:drug therapy* / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D013647:Task Performance and Analysis; D016896:Treatment Outcome
D018687:Antidepressive Agents, Second-Generation; D005473:Fluoxetine