Oculomotor response inhibition abnormalities in pediatric obsessive-compulsive disorder.
BACKGROUND
Disturbances in the orbital prefrontal cortex and its ventral striatal target fields have been identified in neuroimaging studies of obsessive-compulsive disorder (OCD). In animal models and studies of patients with lesions to this brain circuitry, a selective disturbance in the ability to suppress responses to irrelevant stimuli has been demonstrated. Such a deficit in response suppression might underlie the apparent inhibitory deficit suggested by the symptoms of OCD. To date, little direct evidence of such a deficit has been reported. Further, although OCD commonly emerges during childhood or adolescence, few studies have examined psychotropic-naive pediatric patients near the onset of illness to find the possible role of atypical developmental processes in this disorder.


METHODS
Oculomotor tests were administered to 18 psychotropic medication-naive, nondepressed patients with OCD aged 8.8 to 16.9 years and 18 case-matched healthy comparison subjects to assess the following 3 well-delineated aspects of prefrontal cortical function: the ability to suppress responses, the volitional execution of delayed responses, and the anticipation of predictable events.


RESULTS
A significantly higher percentage of response suppression failures was observed in patients with OCD (P = .003), particularly in younger patients compared with their case-matched controls. No significant differences between patients with OCD and controls were observed on other prefrontal cortical functions. Severity of OCD symptoms was related to response suppression deficits.


CONCLUSIONS
A basic disturbance of behavioral inhibition in OCD was detected that may underlie the repetitive symptomatic behavior that characterizes the illness.
Rosenberg
D R
DR
Department of Psychiatry, University of Pittsburgh Medical Center, Pa., USA. Drosen@med.wayne.edu
Averbach
D H
DH
O'Hearn
K M
KM
Seymour
A B
AB
Birmaher
B
B
Sweeney
J A
JA
D000293:Adolescent; D000367:Age Factors; D002648:Child; D003342:Corpus Striatum / Q000502:physiology; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000503:physiopathology; D010555:Personality Inventory; D017397:Prefrontal Cortex / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology; D012720:Severity of Illness Index