Water intoxication in psychiatric patients in Singapore.

The syndrome of water intoxication may occur in psychiatric patients and various hypotheses regarding its aetiology have been postulated. Twenty-seven patients in Woodbridge Hospital were found to have this syndrome. The aim of the study was to describe the clinical and biochemical findings of this group of patients. 70.4% had schizophrenia, 25.9% had mental retardation and 3.7% had a history of alcohol dependence. Many of them were on antipsychotic medication. The symptoms of water intoxication included polyuria, nausea, tremors, weight gain, disorientation, coma and fits. A majority of the patients had hyponatraemia during the acute stages and the osmolality of urine and plasma were correspondingly low. A few patients had abnormalities in electroencephalogram and computerised axial tomography of brain. The management of patients with water intoxication is discussed briefly.