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.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: Readers should be aware that OCD is not associated with above average intellectual abilities (as frequently depicted in TV series such as Monk), but with normative IQ that is slightly lower than non-psychiatric populations.
The myth that OCD may be a associated with this kind of advantage, may lead individuals diagnosed with OCD to be less motivated to seek treatment, which is important because currently individuals with OCD are seeking professional help many years after the onset of the disorder.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Given that an IQ score extracted from a complete IQ test batteries in OCD may be biased due to slowness, we strongly recommend that professionals would choose to administer verbal IQ tests (many of which are found to reliably predict Full Scale IQ) as a mean to more accurately estimate Full Scale IQ.
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Amitai Abramovitch, Gideon Anholt, Sagi Raveh-Gottfried, Naama Hamo, Jonathan S. Abramowitz. Meta-Analysis of Intelligence Quotient (IQ) in Obsessive-Compulsive Disorder. Neuropsychology Review, 2017; DOI: 10.1007/s11065-017-9358-0
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