Identification of primary polydipsia in a severe and persistent mental illness outpatient population: a prospective observational study.

Studies to date have only investigated primary polydipsia in hospitalized psychiatric patient populations, where rates range from 3% to 25%. The objective of the present study was to determine the occurrence of primary polydipsia in a psychiatric outpatient population, and to determine the perceptions of outpatients with self-induced water intoxication regarding reasons for drinking excess fluids, health risks, and insight into their behavior. All 115 psychiatric outpatients from a Community Outreach Program in Kingston, Ontario, were invited to participate in this study. Of these, 89 (77.4%) were enrolled. Data collection included chart reviews, structured interviews, weight measurements, and urine collection. The incidence of primary polydipsia was found to be 15.7%. One-half of the polydipsic people presenting with medical complications suggestive for water intoxication had cigarette smoking as a strong correlate. There were interesting answers to the self-induced water intoxication questionnaire. These showed a lack of knowledge related to the normal quantity of fluids necessary daily and about healthy behaviors. Excessive drinking occurs in psychiatric patient populations outside of institutional/hospital settings. Patients have limited awareness of the severity and possible complications from their problem. Given the prevalence of polydipsia, more effort should be put into identifying and treating this problem.

Mortality over a 20-year period in patients with primary polydipsia associated with schizophrenia: a retrospective study.

Primary polydipsia, excessive fluid intake without medical cause, is present in over 20% of seriously and persistently ill psychiatric inpatients. The long-term effects of primary polydipsia on longevity have not previously been examined. Inpatients in a psychiatric hospital were screened for polydipsia in 1985. Those identified to be polydipsic, the majority of whom suffered from schizophrenia, were re-evaluated in 2005 and compared with a control group of non-polydipsic patients. Chart reviews were conducted and follow-up data were obtained. Of 172 patients at the time of screening, 48 suffering from schizophrenia either had or went on to develop polydipsia; 42 non-polydipsic patients with schizophrenia from the original survey were randomly selected as controls. Primary polydipsia had a significant negative effect on longevity. The median age at death (age at which 50% of cases have died) was 59 years for polydipsic patients and 68 for non-polydipsic control patients. Adjusting for duration of schizophrenia, smoking, and diagnosis, a patient with polydipsia had a 74% greater chance of dying before a non-polydipsic patient (a hazard ratio of 2.84 [95% Confidence Interval (CI): 1.22-6.64]). Outcome was worst in patients with severe polydipsia: the median age at death was 57 years and a patient with severe polydipsia had a 75% greater chance of dying before a non-polydipsic patient (hazard ratio of 3.36 [95% CI: 1.31-8.60]). When polydipsia is associated with schizophrenia, mortality is increased in comparison to that in patients with schizophrenia who do not drink water to excess.