From the Research
The workup for psychogenic polydipsia should begin with a thorough history and physical examination, followed by basic laboratory tests including serum sodium, osmolality, and urine osmolality, as recommended by recent studies 1, 2. The diagnosis of psychogenic polydipsia involves a comprehensive evaluation to rule out other medical causes of polydipsia, polyuria, and hyponatremia.
- A water restriction test is the gold standard diagnostic tool, where fluid intake is restricted under medical supervision while monitoring weight, vital signs, serum sodium, and urine osmolality hourly.
- In true psychogenic polydipsia, urine will concentrate appropriately during water restriction (urine osmolality >300 mOsm/kg) and serum sodium will normalize.
- Additional tests may include measurement of antidiuretic hormone (ADH) levels and brain imaging to rule out central causes. Management primarily involves behavioral interventions such as fluid restriction (typically 1.5-2 liters daily), frequent weight monitoring, and addressing the underlying psychiatric condition with appropriate medications like clozapine or olanzapine for schizophrenia-related polydipsia, as seen in a recent case report 1.
- In severe cases, medications such as demeclocycline (300-600 mg twice daily) or lithium (at lower doses than used for mood disorders) may be considered to induce nephrogenic diabetes insipidus, though these carry significant side effects.
- Regular monitoring of electrolytes is essential during treatment, as rapid correction of hyponatremia can lead to osmotic demyelination syndrome, a complication highlighted in earlier studies 3, 4. The condition is often seen in psychiatric patients, particularly those with schizophrenia, and is thought to result from dysfunction in thirst regulation centers in the brain or as a side effect of certain psychotropic medications, as discussed in a review of primary polydipsia 2.