CT of the brain was carried out in 43 chronic schizophrenics of more than 5 years' duration and less than 60 years of age, and 39 normal controls matched for age, sex and education. There was no statistical difference between controls and schizophrenics as regards cortical atrophy (as measured by the interhemispheric and Sylvian fissures and mean sulcal width). Highly significant differences were found regarding central atrophy. Third ventricle measurements were normal in 9.3%, there was slight enlargement in 37.2%, moderate in 48.8% and extreme in 4.7%. The cella media index denoting lateral ventricle dilatation showed changes in 46.5%, slight in 9.3% and the remaining 44.2% were normal. This study shows that a large number of chronic schizophrenics have an associated central atrophy.