Perceptual changes in schizophrenia: a questionnaire survey.

Questionnaires were completed by 73 volunteers with a history of probable schizophrenia, and by 67 patients admitted to the accident wards of a general hospital. A high incidence of sensory distortions was recorded in the schizophrenic group compared with the controls, distortions of brightness contrast being the most common. Many schizophrenic patients reported that such distortions were reduced or removed early in treatment. Patients who reported visual distortions also tended to report visual hallucinations. The results are discussed with reference to the hypothesis that perceptual malfunction may underlie some other schizophrenic disorders such as delusions or catatonia.