The hypothesis is suggested that voluntary admission to a psychiatric hospital is an event occasioned by a shift in equilibrium of the dyadic relationship between the patient and the central family figure, subsequent to a change in the external environment. Furthermore, the admission is not a function per se of the severity of the patient's symptoms or of his desire for relief. The hypothesis is evaluated by an analysis of 20 patients admitted voluntarily to the New York State Psychiatric Institute. The findings are considered in terms of interpersonal psychodynamics. the implications for treatment are discussed.