Cortical volume abnormalities in schizophrenia: correlations with symptoms and cognitive impairment

Description: Background: Schizophrenic symptoms are known to segregate into reality distortion, negative and disorganization syndromes, but the correlates of these syndromes with regional brain structural change are the subject of conflicting findings. Cognitive impairment is a further clinical feature of schizophrenia, whose brain structural correlates are the subject of conflicting findings. Methods: 165 patients with schizophrenia were rated for symptoms using the PANSS, and cognitive impairment was also indexed by estimated premorbid-current IQ discrepancy. Cortical volume was measured using surface-based morphometry in the patients and in 50 healthy controls. Correlations between clinical and cognitive measures and cortical volume were examined using whole-brain FreeSurfer tools. Results: No clusters of brain volume reduction were seen associated with reality distortion or disorganization. Negative symptom scores showed a significant inverse correlation with cortical volume reduction in a small cluster in the left medial orbitofrontal gyrus. Estimated premorbid-current IQ discrepancy was correlated with clusters of reduced cortical volume in the left precentral gyrus and the left temporal lobe/precentral cortex. The cluster of association with negative symptoms disappeared when estimated premorbid-current IQ discrepancy was controlled for. Conclusions: This study does not provide support for an association between brain structural abnormality and reality distortion or disorganization symptoms in schizophrenia. The cluster of volume reduction in the left medial orbitofrontal cortex associated with negative symptoms may have reflected the association between this class of symptoms and cognitive impairment. The study adds to existing findings of an association between cognitive impairment and brain structural changes in the disorder.