Differential effects of neuroleptic and clozapine on polydipsia and intermittent hyponatremia.

Recent reports indicate that clozapine may dramatically decrease both polydipsia and intermittent hyponatremia associated with chronic psychosis. In contrast, there are conflicting reports regarding the impact of standard neuroleptic treatment in this syndrome. We review the relevant literature examining the effects of antipsychotics on the excessive thirst drive and inordinate arginine vasopressin activity observed in patients with water intoxication. Confounding interpretation of the current literature are inconsistent use of diagnostic criteria and treatment outcome measures. If results of preliminary trials is substantiated, clozapine treatment may provide an opportunity to correct methodological problems and provide greater insight into the syndrome of polydipsia and intermittent hyponatremia.