The relationship between volumetric brain changes and cognitive function: A family study on schizophrenia

We examined the cerebral correlates of intelligence, memory, and executive processing in 56 patients with schizophrenia or schizoaffective disorder and 90 of their nonpsychotic relatives to establish whether the pattern of structure–function relationships in these two groups was different from that in 55 control subjects. Magnetic resonance imaging data were acquired, and volumetric measurements were made for whole brain, prefrontal region, lateral ventricles, third ventricle, temporal lobes, hippocampi, and cerebellum. In the total sample, full intelligence quotient (IQ) and verbal IQ correlated with the volume of the whole brain and right hippocampus; the latter was also associated with performance IQ. Left hippocampal size was associated with verbal IQ and, in control subjects and nonpsychotic relatives only, with estimated full IQ. Delayed verbal memory was linked to cerebellar and inversely to left hippocampal volume. Discrepancies in the relationship pattern emerged in patients with schizophrenia between left hippocampus and measures of IQ and verbal memory. The latter data indicate a loss of a normal structure–function relationship in schizophrenia and might reflect a functional compensation occurring secondary to early neurodevelopmental impairment.