Polydipsia is possible to rule out psychogenic polydipsia or habit polydipsia. Polydipsia is a symptom (evidence of a disease state), not a disease in itself. As it is often accompanied by polyuria, investigations directed at diagnosing diabetes insipidus and diabetes mellitus can be useful. Blood serum tests can also provide useful information about the osmolality of the body's extracellular fluids. A decrease in osmolality caused by excess water intake will decrease the serum concentration of red blood cells, blood urea nitrogen (BUN), and sodium. Polydipsia Polydipsia is excessive thirst or excess drinking. The word derives from the Greek () "very thirsty",
Polydipsia in birds chickens (broilers), subjected routinely to chronic food restriction, show increased drinking after a single daily meal along with other oral stereotypies. Expression of these activities is correlated positively with the level of restriction imposed, and is thought to be controlled mainly by central dopaminergic mechanisms. Under experimental conditions where birds receive reinforcements on a strict schedule, for example receiving one pellet of food each minute often indicated by a tone or other stimulus, the birds may develop polydipsia. Under these conditions it is called schedule induced polydipsia or sometimes, adjunctive drinking. Some strains of hens are polydipsic, drinking almost twice