Self-injurious behavior prevalence and relationships to environmental events.

A survey of 2,858 persons in three institutions indicates an overall prevalence of 14.1% for SIB. Topography of SIB, number of forms in each subject, and intensity and frequency are related to the circumstances surrounding SIB, personnel reactions, age, sex, diagnosis and degree of retardation. Analyses of these relationships provide an SIB profile for the aggressive/severely-profoundly retarded. Direct observation of SIB in the wards indicates a low rate of antecedent and subsequent events. These findings are interpreted in relation to alternative explanatory hypotheses of SIB.