RESUMO
Thalamic abnormalities have been hypothesized to explain much of the psychopathology in schizophrenia, however, quantitative magnetic resonance imaging (MRI) studies have yielded discrepant results as to whether there are thalamic volume alterations. The current study utilized high resolution MRI and an axial voluming protocol to determine if there was a significant reduction in the volume of the thalamus in patients with schizophrenia. Quantitative analysis was performed on magnetic resonance images of the brain in 41 male medicated schizophrenic patients and 39 male normal control subjects similar in age, education and handedness. There were no group differences in thalamic volumes between controls and patients with schizophrenia, even after adjusting for intracranial volume, total brain tissue volume, and gray matter volume. There were also no significant correlations between thalamic volume and either current neuroleptic dose or illness duration. However, there was a significant right greater than left thalamic volume asymmetry in schizophrenics and controls, and the degree of thalamic volume asymmetry was similar in both groups. The failure to detect any significant difference in thalamic volumes may be due to the heterogeneity of the schizophrenic population and as yet undetermined chronic effects of neuroleptic medication on the thalamus. However, another reasonable explanation for the study findings is that quantitative MRI voluming of the entire thalamus may not be sensitive enough to detect more subtle regional neuropathology within the thalamus.