Temporal horn enlargement is present in schizophrenia and bipolar disorder

Background: Ventricular enlargement and temporal lobe volume deficits have been demonstrated in patients with affective disorder as well as those with schizophrenia. This study compares quantitative measures of temporal lobe, hemispheric, and ventricular volumes in a group of patients with chronic schizophrenia and bipolar disorder and seeks to determine if the groups can be differentiated on the basis of measured brain abnormalities. Methods: A series of coronal magnetic resonance imaging sections were acquired and analyzed for each of 22 patients with chronic schizophrenia, 14 patients with bipolar disorder, and 15 community volunteers. Eleven regions of interest for each brain were defined, which included temporal lobe, superior temporal gyrus, hemisphere, lateral ventricle, third ventricle, and temporal horn measures. Tissue measures were obtained by tracing, and cerebrospinal fluid measures were obtained by fluid–tissue thresholding using specialized computer software. Results: Both patient groups had significantly larger temporal horn volumes in comparison with the control group both before and after correction for intracranial volume. The two patient groups did not differ from each other or controls on any other tissue or fluid measure. Conclusions: This study confirms the finding of increased temporal horn volume in patients with schizophrenia and suggests that this structural abnormality does not differentiate the structural neuropathology of schizophrenia from that of bipolar disorder.