Schizophrenia patients with polydipsia and water intoxication are characterized by greater severity of psychotic illness and a more frequent history of alcohol abuse

Polydipsia and water intoxication (PWI) are relatively frequent among schizophrenic subjects, particularly in institutional settings and may lead to severe complications. However, little is known on their association with other characteristics of psychosis. Hence, we took advantage of a cohort of 114 subjects extensively assessed on natural history and clinical variables to examine the correlates of PWI in chronic schizophrenia. We randomly sampled DSM-IV schizophrenic subjects from: i) a lower functioning subgroup, i.e., long-term psychiatric wards or highly structured group housing facilities; and ii) a higher functioning subgroup, i.e., patients living in the community without supervision. Subjects were assessed from multiple sources for lifetime severity of positive, disorganisation, negative and depressive symptoms, premorbid adjustment, age of onset, level of functioning, comorbid diagnoses of substance abuse and lifetime history of PWI. Twelve subjects (10.5%) met our PWI criteria. We observed more severe psychotic symptoms, earlier onset, poorer current adjustment and more frequent prior alcohol use disorder in PWI subjects. When restricting comparisons to patients living in institutional setting, differences on clinical and natural history variables vanished but the association between PWI and prior alcohol abuse persisted (72.7% in PWI vs. 21.4% in non-PWI subjects, p