An MRI study of temporal lobe structures in men with bipolar disorder or schizophrenia

Background: Hippocampal atrophy has been described in postmortem and magnet ic resonance imaging studies of schizophrenia The specificity of this findi ng to schizophrenia remains to be determined, The neuropathology of bipolar disorder is understudied, and temporal lobe structures have only recently been evaluated. Methods: Twenty-four bipolar, 20 schizophrenic, and 18 normal comparison su bjects were evaluated using magnetic resonance brain imaging, Image data we re acquired using a three-dimensional spoiled GRASS sequence, and brain ima ges were reformatted in three planes. Temporal lobe structures including th e amygdala, hippocampus, parahippocampus, and total temporal lobe were meas ured to obtain volumes for each structure in the three subject groups, Seve rity of symptoms in both patient groups was assessed at the time the magnet ic resonance images were obtained. Results: Hippocampal volumes were significantly smaller in rite schizophren ic group than in both bipolar and normal comparison subjects, Further, amyg dala volumes were significantly larger in the bipolar group than in both sc hizophrenic and normal comparison subjects. Conclusions: The results suggest differences in affected limbic structures in patients with schizophrenia and bipolar disorder. These specific neuroan atomic abnormalities may shed light on the underlying pathophysiology and p resentation of the two disorders. Biol Psychiatry 2000; 48:147-162 (C) 2000 Society of Biological Psychiatry.