A "biofeedback" approach to the treatment of chronic polydipsia.

A novel behavioral method is described for the treatment of psychogenic polydipsia in a patient suffering from chronic schizophrenia. The patient was given feedback on serum sodium concentration, likely physical consequences, and the value of reducing fluid intake. An ABAB single-case design was used, with changes in sodium concentration (charted by the patient during the treatment phases) as the dependent variable. The patient showed substantially increased sodium concentration, which was maintained despite the withdrawal of feedback. This behavioral method appears promising in settings where restriction of fluid intake is not practical or ethical.