Behavioral analysis of drinking behaviors in polydipsic patients with chronic schizophrenia.

The authors describe drinking and voiding behaviors that differentiate between psychiatric patients with polydipsia and patient controls. Observations of 9 polydipsic patients and 6 controls were conducted for 153 hr and had high interrater reliability. Polydipsic patients drank 3 times as frequently, ingesting 5 times as much fluid as the controls. They voided 4 times as often, eliminated 5 times as much urine, and evidenced greater diurnal weight shifts. A higher bout frequency and a shorter time interval between drinks differentiated polydipsic patients from controls, whereas amount drunk per bout and rate of drinking were similar across groups. The authors' findings have implications for improving detection of polydipsia, understanding its neurobiology, and developing more efficacious behavioral interventions.