Polydipsia

A persistent, excessive or abnormal thirst, often associated with increased fluid intake. Possible causes are diabetes mellitus, diabetes insipidus, dehydration (profuse sweating, vomiting, diarrhea, hemorrhage), medications (diuretics, lithium, antipsychotics, anticholinergics), psychiatric conditions (schizophrenia), hyperthyroidism, kidney failure, heart/liver/lung failure.