['To test the hypothesis that 1-desamino-8-D-arginine vasopressin (dDAVP) has an effect on prepulse inhibition (PPI) of startle in patients with primary monosymptomatic enuresis (PME), thus indicating a central effect.', 'Patients with PME (n = 21, age 6 to 12 years) were enrolled in a prospective, randomized, double-blinded, cross-over study. Startle reflexes and PPI were measured under dDAVP treatment versus placebo.', 'The data show that dDAVP has a significant effect on PPI, raising it from 38.88% under placebo to the age-related normal level of 62.6% with dDAVP treatment (P = .0127).'] Does effect of 1-desamino-8-D-arginine vasopressin on prepulse inhibition of startle support a central etiology of primary monosymptomatic enuresis?