The thalamus and the schizophrenia phenotype: failure to replicate reduced volume

Background: Thalamic abnormalities resulting in impaired attention and information processing may form a foundation for cognitive and perceptual disturbances in schizophrenia. Measurements of the thalamus in patients with schizophrenia have shown reductions relative to normal comparison subjects. Methods: In the current project, magnetic resonance images of the brain were obtained in 10 male and 11 female subjects with paranoid-type schizophrenia, and 15 male and 12 female normal comparison subjects. Total brain and bilateral thalamic volumes were calculated. Results: There were no significant diagnosis, hemisphere, or gender differences in thalamic volumes. Conclusions: Structural thalamic abnormalities are not likely to universally and parsimoniously explain the schizophrenia phenotype. Abnormal thalamic size in patients with schizophrenia should be understood as reflecting one of several possible structural abnormalities contributing to production of the schizophrenia phenotype, but must be regarded with caution unless paired with functional studies.