The medical and psychological investigation of psychogenic polydipsia: a case study.

The case of a 17 year-old female with psychogenic polydipsia is reported; 13 out of 18 members of her maternal family were known to have had polydipsia and polyuria, but only two had undergone endocrine investigations--one had diabetes insipidus and one also had psychogenic polydipsia. There are probable contributions of non-genetic family factors including imitation and identification to the development of this patient's condition. Detailed family and developmental histories may be of particular assistance in the understanding of the psychogenesis of the disorder in some patients.