Polyuria among patients with psychosis.

Using the criterion of early morning urinary specific gravity (SPGR) of 1.008 or less to define the presence of polyuria, we identified 26 of 72 male (36 percent) and 14 of 31 female (45 percent) institutionalized chronically psychotic patients as polyuric during a comprehensive survey of one of the chronic care units at a State mental hospital. Factors including diagnosis, sex, age, weight, and serum sodium did not distinguish the polyuric from the nonpolyuric patients. For men, administration of lithium was associated with polyuria. Urinary creatinine concentration (UCR) correlated well with SPGR, and UCR may provide an alternate index to separate polyuric from nonpolyuric patients. The clinical implications of our findings are discussed.