Polydipsia is a medical term meaning abnormally large (poly-) intake of fluids by mouth. That is, drinking (-dipsia). The fluid is usually water, though some people may think of alcohol because of the etymologically related term dipsomaniac, meaning an alcoholic.
Polydipsia is almost always associated with polyuria (excessive urination), if the condition is prolonged beyond a few hours in those with functioning kidneys.
It is often, and characteristically, found in diabetics, often as one of the initial symptoms, and in those who fail to take their anti-diabetic medications or whose dosages have become inadequate. It is also caused by other conditions featuring osmotic diuresis and by diabetes insipidus ("water diabetes"), and forms part of the differential diagnosic tree for them as well. It has also been suggested that many people with Tourette's Syndrome suffer from polydipsia, often drinking the equivalant of fifteen or more glasses of water per day.
Psychogenic polydipsia is a very rare psychological disorder sometimes described in hospitalized schizophrenics.
See also