Drinking and urinating excessively

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Polydipsia is excessive thirst or excess drinking. The word derives from Greek terms meaning 'very thirsty'. It is a nonspecific symptom in various medical disorders. Polydipsia is a symptom, not a disease in itself. It is often accompanied by polyuria, which is excessive urination.

Key facts

Polydipsia can be characteristic of diabetes mellitus, often as an initial symptom. It is observed in cases of poorly controlled diabetes. Diabetes insipidus can also cause polydipsia. It can be caused by a change in the osmolality of the extracellular fluids of the body, hypokalemia, decreased blood volume, and other conditions that create a water deficit. Polydipsia is also a symptom of anticholinergic poisoning. A zinc deficiency can be a possible cause. The combination of polydipsia and polyuria is also seen in primary hyperaldosteronism. Antipsychotics can have side effects such as dry mouth that may make the patient feel thirsty. Primary polydipsia describes excessive thirst and water intake caused in the absence of physiological stimuli to drink. Psychogenic polydipsia is an excessive water intake seen in some patients with mental illnesses such as schizophrenia, or with developmental disabilities. The amount of water ingested can exceed the amount that can be excreted by the kidneys. Habit drinking is a milder form typically found in the absence of psychosis or other mental conditions. The chronic ingestion of excessive water can produce diagnostic results that closely mimic those of mild diabetes insipidus.

When to seek professional help

Professional help is associated with diagnosing the underlying disease state for which polydipsia is a symptom. Investigations directed at diagnosing diabetes insipidus and diabetes mellitus can be useful. Blood serum tests can provide useful information about the osmolality of the body's extracellular fluids. A water deprivation test may be used to make a distinction between conditions. Prior to a water deprivation test, consideration should be given to a psychiatric consult to see whether it is possible to rule out psychogenic polydipsia or habit polydipsia. Psychogenic polydipsia should be taken very seriously, as it can on rare occasions be life-threatening.

Source: Polydipsia (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-09-25.