TEMPORAL-LOBE METABOLIC DIFFERENCES IN MEDICATION-FREE OUTPATIENTS WITH SCHIZOPHRENIA VIA THE PET-600

Regional cerebral glucose metabolic rates (rCMRglc) were compared in 1 8 unmedicated outpatients with schizophrenia and 12 normal controls us ing high resolution positron emission tomography (PET) and the tracer [F-18]-2-fluoro-2D-deoxyglucose (FDG). From previous work we expected to see abnormal hippocampal rCMRglc in the patients, but no striatal a bnormalities. Trial-by-trial Stroop cognitive task, which has been sho wn to activate the anterior cingulate, was performed within a day of t he PET study. As our patients performed abnormally on the Stroop we te sted for a correlation between the anterior cingulate rCMRglc and Stro op performance. We found no whole slice cortical average glucose metab olic abnormalities. As predicted we found abnormally decreased left hi ppocampal rCMRglc in the patients. No striatal or cingulate rCMRglc ab normalities were noted in patients, but they demonstrated a highly pos itive correlation between anterior and cingulate rCMRglc and Stroop fa cilitation. Patients with higher Stroop interference had more prominen t hippocampal metabolic decreases. These localized temporal lobe abnor malities could account for some of the patient's positive symptoms and are consistent with recent findings in the literature. (C) 1996 Ameri can College of Neuropsychopharmacology