[Successful clozapine treatment of primary polydipsia associated with hyponatraemia in a schizophrenic patient. A case report].

Polydipsia is the intake of more than 3-4 litres of fluids per day. Primary polydipsia (PP) occurs when excessive fluid intake cannot be explained by an identified medical condition. PP has a prevalence varying between 6% and 20% in the population of chronically hospitalized psychiatric patients. Hyponatraemia--sometimes with severe somatic consequences--developing in 25-86% of these patients. We discuss the case of a schizophrenic patient who had polydipsia, polyuria and hyponatremia without any known medical conditions in the etiological background of these symptoms. In accordance with data of literature, clozapine medication was effective in the treatment of this severe condition.