Psychogenic Polydipsia is defined as the desire to drink liquid in big quantities with an inappropriate activation of the mechanisms of thirst without loss of liquid for urine. This disorder is frequent enough and can derive in a water poisoning, a clinical presentation of high mortality.

Review of the Psychogenic Polydipsia in patients with schizophrenia and theoretical discussion of a case report.

A case report of a 58-year-old male, admitted in hospital with a clinical presentation of hyponatremia with severe low serum osmolarity secondary to Psychogenic Polydipsia. As psychiatric history he has a diagnosis of Paranoid Schizophrenia for forty years in treatment with Paliperidone 6 mg: 1-0-0, Haloperidol 10 mg: 0-0-0.5, Quetiapina 300 mg: 0-0-1, Trazodona 100 mg: 0-0-1, Ketazolam 30 mg: 0-0-1, Diazepam 10 mg: 0-0-1.

Psychogenic Polydipsia is not included in any section of current psychiatric classifications as specific diagnosis. There are several psychiatric disorders that may present with psychogenic polydipsia; however, the most common cause appears to be schizophrenia.

Mechanisms of hyponatremia in patients with schizophrenia are not well clarified; nevertheless, dopamine seems to be the common link between psychogenic polydipsia and schizophrenia.

The authors have not supplied their declaration of competing interest.