Functional neuroimaging can elucidate brain dysfunction in schizophrenia. The frontal, temporolimbic, and diencephalic regions have been implicated. There is a lack of prospective samples of firstepisode and previously treated patients followed up longitudinally.
Patients and controls (42 per group) were studied. Positron emission tomography with fluorodeoxyglucose, cross-registered with magnetic resonance imaging, measured metabolism. Scales assessed clinical features, premorbid adjustment, and outcome.
There were no differences between groups in whole-brain metabolism or regional ratios or in anterior-posterior gradients, but left midtemporal metabolism was relatively higher in patients. This was pronounced in the negative and Schneiderian and absent in the paranoid subtypes. Higher metabolism and lower relative left hemispheric values were associated with better premorbid adjustment and outcome. A higher subcortical-cortical gradient was noted in first-episode patients.
There are no resting metabolic abnormalities in any brain region, but abnormal gradients are evident. These vary in subtypes, and laterality is associated with functioning. The results support the hypothesis of temporolimbic disturbance in schizophrenia that is already present at the onset of illness.