Structural brain abnormalities in patients with schizophrenia, epilepsy, and epilepsy with chronic interictal psychosis

Chronic interictal psychotic syndromes, often resembling schizophrenia, develop in some patients with epilepsy. Although widespread brain abnormalities are recognized as characteristic of schizophrenia, prevailing but controversial hypotheses on the co-occurrence of epilepsy and psychosis implicate left temporal lobe pathology. In this study, quantitative MRI methods were used to address the regional specificity of structural brain abnormalities in patients with epilepsy plus chronic interictal psychosis (E + PSY, n = 9) relative to three comparison groups: unilateral temporal lobe epilepsy without chronic psychosis (TLE, n = 18), schizophrenia (SCZ, n = 46), and healthy control subjects (HC, n = 57). Brain measures, derived from a coronal spin-echo MRI sequence, were adjusted for age and cerebral volume. Relative to HC, all patient groups had ventricular enlargement and smaller temporal lobe, frontoparietal, and superior temporal gyrus gray matter volumes, with the extent of these abnormalities greatest in E + PSY. Only TLE had temporal lobe white matter deficits, as well as smaller hippocampi, which were ipsilateral to the seizure focus. Structural brain abnormalities in E + PSY are not restricted to the left temporal lobe. The confluence of cortical gray matter deficits in E + PSY and SCZ suggests salience to chronic psychosis.