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 PARTICIPANTSCase-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 MEASURESAssociations 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 <.001 and .03 after clusterwise correction). Although IQ increased similarly in patients with schizophrenia and control participants, changes in IQ were negatively correlated with changes in lateral ventricular volume (P = .05) and positively correlated with changes in cortical volume (P = .007) and thickness (P = .004) only in patients with schizophrenia. Positive correlations between changes in IQ and cortical volume and thickness were found globally and in widespread regions across frontal, temporal, and parietal cortices (P values were between <.001 and .03 after clusterwise correction). These findings were independent of symptom severity at follow-up, cannabis use, and the use of cumulative antipsychotic medications during the 3 years of follow-up.CONCLUSIONS AND RELEVANCE Progressive brain tissue loss in schizophrenia is related to relative cognitive decline during the early course of illness.

Progressive Reduction in Gray Matter in Patients with Schizophrenia Assessed with MR Imaging by Using Causal Network Analysis

“…The illness duration of SZ was associated with GM atrophy progressing from the thalamus to the frontal lobe and then to the temporal lobe, occipital cortices, and the cerebellum. This progressive atrophy pattern in these regions has been observed in patients with a first-episode of or chronic SZ (23)(24)(25)(26)(27)(28). In particular stages of illness, lower GM volume in the frontal lobe and the postcentral gyrus was linked to longer disease duration, consistent with results from previous studies (22,29).…”

Immune involvement in the pathogenesis of schizophrenia: a meta-analysis on postmortem brain studies

“…61 Their underlying pathophysiology, however, remains unclear. As increased activation of the CNS immune system leads to decreased production of brain-derived neurotrophic factor and other neurotrophic factors, this process, together with the production of neurotoxic proinflammatory factors such as IL-6, TNFα and IL-1β, may contribute to brain volume loss in schizophrenia.…”

Eye‐movement characteristics of schizophrenia and their association with cortical thickness

“…Our present results reveal novel associations between eye‐movement measures and cortical thickness of the left pars opercularis in SCZ. Eye movements are known to be associated with Wechsler Adult Intelligence Scale (WAIS)‐III measures and cortical thickness alterations have been linked to changes of intellectual functioning in SCZ . After controlling for further factors related to intelligence and education (education, estimated premorbid IQ, and WAIS‐III full‐scale IQ), these correlations were weakened (integrated eye‐movement score, R = 0.23, p = 2.63 × 10 −2 ; scanpath length, R = 0.26, p = 1.28 × 10 −2 ; see Table S4 for full results in participants with SCZ and Table S5 for results in healthy controls).…”