Psychogenic polydipsia

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Psychogenic polydipsia is a special form of polydipsia, caused by mental disorders.

The patient drinks large amounts of water, which raises the pressure of the extracellular medium. As a side effect, the antidiuretic hormone level is lowered. The urine produced by these patients will have a low electrolyte concentration and it will be produced in large quantities (polyuria). If the patient is institutionalised, close monitoring by staff is necessary to control fluid intake.

While psychogenic polydipsia is usually not seen outside the population of those with serious mental disorders, it may occasionally be found among others in the absence of psychosis, although there is no extant research to document this other than anecdotal observations. Such persons typically prefer to possess bottled water that is ice cold, consume water and other fluids at excessive levels, and may be falsely diagnosed as suffering from diabetes insipidus, since the chronic ingestion of excessive water can produce symptoms and diagnostic results that mimic mild diabetes insipidus.

Psychiatric watchdog groups have periodically raised concerns that psychogenic polydipsia may be nothing more than a scapegoat-disorder to explain the deaths of mental patients treated with psychiatric medication known by science to cause hyponatremia, a potentially fatal consequence of severe prolonged polydipsia, while in psychiatric care. One argument put forth is the fact that a healthy human being weighing +-165 lbs (+-75 Kg) has to consume atleast 2.1 Gallons (8 Liters) of water a day for a period of two weeks to develop severe hyponatremia. It is claimed by these groups that it is highly unlikely that any psychiatric patient is able to consume such a vast amount of fluid without being noticed.