GM reductions in psychotic BD patients ‘nonsignificant’
MedWire News: Gray matter (GM) volume reductions in bipolar disorder (BD) patients with psychosis are not as pronounced as those in patients with schizophrenia, results from a US study suggest.
"Schizophrenia is characterized by well documented gray matter abnormalities in multiple frontal, temporal, and subcortical structures," explain Cagri Yüksel (McLean Hospital, Belmont, Massachusetts) and team in Schizophrenia Research.
They add: "Psychosis, a hallmark of schizophrenia, is also experienced by a significant proportion of BD patients and there is evidence that psychotic bipolar disorder may be characterized by specific clinical and pathophysiological features.
"However, there are few studies comparing gray matter between schizophrenia and psychotic BD [patients]."
To address this, the team studied 58 patients with schizophrenia, 28 with bipolar I disorder who were experiencing psychotic symptoms, and 43 mentally healthy controls. There were no significant between-group differences in mean age, gender distribution, or handedness.
All of the participants underwent structural magnetic resonance imaging scans, and GM volume was assessed using whole-brain voxel-based morphometry.
Analysis revealed that schizophrenia patients had significantly reduced GM volume compared with controls in multiple frontal and temporal regions. These regions included the bilateral anterior cingulate cortex, orbitofrontal cortex, inferior frontal gyri, insula, precentral gyrus, right superior temporal gyrus, left superior, middle and inferior temporal gyri, and right precuneal cortex.
Schizophrenia patients also showed significantly increased GM volume compared with controls in one brain region, namely the right cerebellum, posterior lobe.
By contrast, BD patients with psychosis showed no significant GM volume differences compared with controls or schizophrenia patients.
The researchers note that there was no significant correlation between GM volume in any brain region and antipsychotic medication use in either BD or schizophrenia patients.
Yüksel and team conclude that "gray matter abnormality as measured by voxel-based morphometry analysis is less pronounced in psychotic BD compared to schizophrenia [patients]."
They add: "This may be due to disease-specific factors or medications used more commonly in BD."
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By Mark Cowen