Ventricular and Sulcal Size at the Onset of Psychosis
To determine whether abnormalities in brain morphology are present at the onset of illness, patients with schizophrenia (n=31), schizophreniform (n=20) and bipolar disorders (n=18), and major depression (n=16) who were experiencing their first episodes of psychosis were compared with normal (n=44) and medical control (n=30) subjects. All subjects were given computerized tomography (CT) scans which were quantified without knowledge of subject diagnosis. Lateral ventricle size was estimated by calculating the ventricle-to-brain ratio for the CT slice that showed the lateral ventricles at their largest. Third ventricle measurements were made using a traveling microscope to assess ventricle width. A three-point rating scale was used to assess the visibility of the cortical sulci on the CT scan that was three slices above the scan that showed the lateral ventricles at their largest.