MedicalResearch.com Interview with:
Amitai Abramovitch, PhD
Department of Psychology
Texas State University
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Obsessive-Compulsive Disorder (OCD) is associated with moderate degree of underperformance on several cognitive tests such as processing speed, and some higher order functions such as planning and inhibition. While this does not constitute a clinically meaningful impairment on these functions, we set out to explore the prevailing myth that OCD is associated with above-average intelligence. This myth, that was propagated by Sigmund Freud 115 years ago and is still surprisingly all too prevalent – was never tested empirically. The notion of above average intelligence in OCD didn’t make sense to us given that IQ tests are comprised of subtests that assess cognitive function. To test this, we collected all the available data ever published in the scientific literature regarding IQ in OCD versus control samples, and conducted a meta-analysis. Our results show that OCD is not associated with higher IQ than average. In fact we found a slightly lowered IQ in OCD compared to controls, although IQ scores for OCD samples were in the average range. The total IQ score (Full Scale IQ) is comprised of two subscales, namely Verbal IQ, and Performance IQ.
Our results show that reduced Full Scale IQ stems primarily from lowered Performance IQ, a scale that is comprised of a number of timed tests. In other words, as opposed to Verbal IQ tests, test scores on Performance IQ subtests rely heavily on performance within a specific time frame, and not only on performance accuracy.
Thus, our findings suggest that reduced processing speed found in OCD could lead to reduced Performance IQ, and subsequently lead to lowered Full Scale IQ, and may not be indicative of specific cognitive deficits. This finding suggests that IQ tests administered to individuals diagnosed with OCD may result in a biased Full Scale IQ scores that does not accurately reflect their full intellectual potential.