A computerized neuropsychological evaluation of cognitive functions in a subclinical obsessive-compulsive sample.

BACKGROUND AND OBJECTIVES: Ample research in obsessive-compulsive disorder (OCD) reveals a moderate degree of underperformance on various neuropsychological tasks. Less is known about neuropsychological function in subclinical obsessive-compulsive (OC) samples. Most analogue OCD studies did not use a comprehensive neuropsychological battery and none utilized a fully computerized battery. To fill this gap in the literature, the present study aimed at assessing cognitive functions in a subclinical OC sample using a validated computerized neuropsychological battery. METHODS: Initially, a sample of 165 students completed the Obsessive-Compulsive Inventory-Revised (OCI-R). Using a psychometrically valid methodology, a high OC (HOC, n = 29) and low OC (LOC, n = 29) groups were selected based on scores in the upper and lower quartiles on the OCI-R. The two groups completed the NeuroTrax computerized neuropsychological battery and clinical questionnaires. RESULTS: Although the HOC group underperformed on most outcome measures, controlling for state-anxiety and depression symptoms, no significant differences were found on major domains (i.e., memory, attention, executive functions, processing speed, visuospatial functions, verbal functions, and motor skills), and subdomains. Normalized scores, produced using population norms, indicated that both groups performed within the normative range. LIMITATIONS: Not all neuropsychological subdomains were assessed. CONCLUSIONS: Results are consistent with the general picture in analogue OC samples, and may be more reliable than paper-pencil testing, given that a full computerized neuropsychological battery minimizes examiner-examinee interactions, and increases timing accuracy. In sum, analogue OC samples, characterized by equivalent symptom severity but high functioning compared to OCD samples, do not present with cognitive deficits.

Meta-Analysis of Intelligence Quotient (IQ) in Obsessive-Compulsive Disorder.

Obsessive compulsive disorder (OCD) is associated with a moderate degree of underperformance on cognitive tests, including deficient processing speed. However, despite little research focusing on Intelligence Quotient (IQ) in OCD, it has long been speculated that the disorder is associated with elevated intellectual capacity. The present meta-analytic study was, therefore, conducted to quantitatively summarize the literature on IQ in OCD systematically. We identified 98 studies containing IQ data among individuals with OCD and non-psychiatric comparison groups, and computed 108 effect sizes for Verbal IQ (VIQ, n = 55), Performance IQ (PIQ, n = 13), and Full Scale IQ (FSIQ, n = 40). Across studies, small effect sizes were found for FSIQ and VIQ, and a moderate effect size for PIQ, exemplifying reduced IQ in OCD. However, mean IQ scores across OCD samples were in the normative range. Moderator analyses revealed no significant moderating effect across clinical and demographic indices. We conclude that, although lower than controls, OCD is associated with normative FSIQ and VIQ, and relatively lowered PIQ. These results are discussed in light of neuropsychological research in OCD, and particularly the putative impact of reduced processing speed in this population. Recommendations for utilization of IQ tests in OCD, and directions for future studies are offered.