Brain structural changes in schizoaffective disorder compared to schizophrenia and bipolar disorder

Abstract

Objective: Brain structural changes in schizoaffective disorder, and how far they resemble those seen in schizophrenia and bipolar disorder, have only been studied to a limited extent.

Method: Forty-five patients meeting DSM-IV and RDC criteria for schizoaffective disorder, groups of patients with 45 matched schizophrenia and bipolar disorder, and 45 matched healthy controls were examined using voxel-based morphometry (VBM).

Results: Analyses comparing each patient group with the healthy control subjects found that the patients with schizoaffective disorder and the patients with schizophrenia showed widespread and overlapping areas of significant volume reduction, but the patients with bipolar disorder did not. A subsequent analysis compared the combined group of patients with the controls followed by extraction of clusters. In regions where the patients differed significantly from the controls, no significant differences in mean volume between patients with schizoaffective disorder and patients with schizophrenia in any of five regions of volume reduction were found, but mean volumes in the patients with bipolar disorder were significantly smaller in three of five.

Conclusion: The findings provide evidence that, in terms of structural gray matter brain abnormality, schizoaffective disorder resembles schizophrenia more than bipolar disorder.

Keywords: bipolar disorder; neuroimaging; schizo-phrenia; schizoaffective disorder; voxel-based morphometry.

Figure 1

Brain regions showing significant gray matter volume reduction in patients with schizophrenia and schizoaffective disorder in relation to the healthy controls group (n = 45) at P < 0.01, corrected for multiple comparison across space via a threshold‐free cluster enhancement procedure. Top panel (a) Volume reductions in the patients with schizophrenia (n = 45). Bottom panel (b) Volume reductions in the patients with schizoaffective disorder (n = 45). The patients with bipolar disorder showed no areas of volume reduction. The right side of the image is the right side of the brain.

Figure 2

Comparisons of gray matter volume reduction averaged over the clusters in schizoaffective disorder (n = 45), schizophrenia (n = 45), and bipolar disorder (n = 45) in the following regions: (a) ventromedial prefrontal cortex, (b) bilateral frontal superior cortex, (c) right temporo‐insular‐parietal areas, (d) left temporo‐insular‐parietal areas, and (e) bilateral cerebellum. Boxplots are based on mean percentage of volume reduction compared to the healthy controls group. ** individual t‐tests significant at a corrected P < 0.01, * significant at a corrected P < 0.05. The right side of the image is the right side of the brain.