Background
Psychogenic polydipsia or primary polydipsia (PPD) is a disorder characterized by excessive thirst and compulsive water drinking. It may occur in both nonpsychiatric and psychiatric patients. PPD is a poorly understood, underdiagnosed disorder in patients with mental disorders. It is associated with reduced life-expectancy in patients with schizophrenia, independently from psychiatric diagnosis, because of the many, and often serious, clinical complications.
Case reports
We present three cases of psychogenic polydipsia in psychiatric patients with long-term psychiatric mental illness and exposure to neuroleptics. PPD onset is associated with somatic delusions, dry mouth, and stressful events, respectively; those symptoms and events are broadly described in the literature. The first is a case of PPD with an episode of SIWI (self-induced water intoxication), the second is a case of simple polydipsia, and the third is a case of PPD associated with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). We briefly discussed risk factors for PPD.