Severe hypernatremia in a patient with psychiatric illness.

A 17-year-old schizophrenic developed severe hypernatremia during a period of psychosis. The thirst-deficient abnormality that caused this hypernatremia resolved when his psychosis improved. The primary disorders causing a thirst deficiency leading to hypernatremia fall into three categories: lesions of the central nervous system, mineralocorticoid excess, and drug side effects. None of these disorders was found in our patient. We conclude that psychosis can severely impair the thirst mechanism directly.