Primary polydipsia rare non-psychogenic causes. An example is polydipsia found in patients with autoimmune chronic hepatitis with severely elevated globulin levels. Evidence for the thirst being non-psychogenic is gained from the fact that it disappears after treatment of the underlying disease. Psychogenic polydipsia is also observed in some non-human patients, such as in rats. Primary polydipsia Primary polydipsia is a form of polydipsia characterised by excessive fluid intake in the absence of physiological stimuli to drink. This includes psychogenic polydipsia (PPD – not to be confused with postpartum depression), which is caused by psychiatric disorders, often schizophrenia, and often accompanied by the
Polydipsia decreased blood volume (as occurs during major hemorrhage), and other conditions that create a water deficit. This is usually a result of osmotic diuresis. Diabetes insipidus ("tasteless" diabetes, as opposed to diabetes mellitus) can also cause polydipsia. Polydipsia is also a symptom of anticholinergic poisoning. Zinc is also known to reduce symptoms of polydipsia by causing the body to absorb fluids more efficiently (reduction of diarrhea, induces constipation) and it causes the body to retain more sodium; thus a zinc deficiency can be a possible cause. The combination of polydipsia and (nocturnal) polyuria is also seen in (primary) hyperaldosteronism (which