Changes in cortical volume and thickness are significantly associated with IQ changes in individuals with schizophrenia, according to a case-control longitudinal study in 84 patients with schizophrenia and 116 age-matched healthy controls.
Researchers compared magnetic resonance imaging at baseline and the 3-year follow-up with patients’ IQ scores. They found that a decrease in IQ was associated with a decrease in cortical volume and less cortical thickening, but increased lateral ventricular volume, in patients with schizophrenia but not controls.
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The study, published online June 17 in JAMA Psychiatry, showed significant relationships between IQ changes and brain tissue changes in patients with schizophrenia across the frontal, temporal, parietal, and cingulate cortices, and in the cortical surface areas of the frontal pole, right temporal, left postcentral, left precuneus, and left occipital regions.
“The effect might be explained by a subgroup characterized by both cognitive deterioration and brain tissue loss, which could well be clinically and genetically distinct with implications for diagnosis, treatment, and drug development,” wrote Dr. Manubu Kubota and colleagues from the University Medical Center Utrecht, the Netherlands (JAMA Psychiatry 2015 June 17 [doi:10.1001/jamapsychiatry.2015.0712]).
The study was supported by the Dutch Health Research Council and the Uehara Memorial Foundation. There were no conflicts of interest declared.