Association of IQ Changes and Progressive Brain Changes in Patients With Schizophrenia

Abstract

IMPORTANCE Although schizophrenia is characterized by impairments in intelligence and the loss of brain volume, the relationship between changes in IQ and brain measures is not clear. OBJECTIVE To investigate the association between IQ and brain measures in patients with schizophrenia across time. DESIGN, SETTING, AND PARTICIPANTS Case-control longitudinal study at the Department of Psychiatry at the University Medical Center Utrecht, Utrecht, the Netherlands, comparing patients with schizophrenia and healthy control participants between September 22, 2004, and April 17, 2008. Magnetic resonance imaging of the brain and IQ scores were obtained at baseline and the 3-year follow-up. Participants included 84 patients with schizophrenia (mean illness duration, 4.35 years) and 116 age-matched healthy control participants. MAIN OUTCOMES AND MEASURES Associations between changes in IQ and the total brain, cerebral gray matter, cerebral white matter, lateral ventricular, third ventricles, cortical, and subcortical volumes; cortical thickness; and cortical surface area. RESULTS Cerebral gray matter volume (P = .006) and cortical volume (P = .03) and thickness (P = .02) decreased more in patients with schizophrenia across time compared with control participants. Patients showed additional loss in cortical volume and thickness of the right supramarginal, posterior superior temporal, left supramarginal, left postcentral, and occipital regions (P values were between CONCLUSIONS AND RELEVANCE Progressive brain tissue loss in schizophrenia is related to relative cognitive decline during the early course of illness.