BackgroundConverging evidence has suggested that the abnormalities in brain morphology observed in schizophrenia are similar to those seen in temporal lobe epilepsy (TLE). The purpose ofthis study was to compare the features of these groups directly with measures of the brain using magnetic resonance (MR) morphometry.MethodMorphometric measures of ventricular and hippocampal volumes obtained from FLASH MR images were studied in 32 patients with first-episode schizophrenia (FES), 39 patients withTLE (21 left, 18 right), and 42 healthy controls.ResultsVentricular volumes in the FES and TLE groups were both significantly larger than those seen in controls and did not differ from each other. The FES group showed significantly larger temporal horns, while theTLE group had relatively larger frontal horns. Analyses of hippocampal volumes revealed a significant group by hemisphere effect. The FES group showed relative reductions in left hippocampal volume that were comparable only toTLE patients with seizures originating from the left hemisphere.ConclusionThe results indicate that FES and TLE groups both show evidence of ventricular enlargement. Lateralised morphological abnormalities of the hippocampal formation in FES and left TLE are comparable, and may be specific to temporolimbic regions.