Prader-Willi syndrome (PWS) is a complex neurodevelopmental genetic disorder with hypothalamic dysfunction, early morbid obesity with hyperphagia, and specific psychiatric phenotypes including cognitive and behavioural problems, particularly disruptive behaviours and frequent temper outbursts that preclude socialization. A deficit in oxytocin (OT)-producing neurons of the hypothalamic paraventricular nucleus has been reported in these patients.

In a double-blind, randomised, placebo-controlled study, 24 adult patients with PWS received a single intranasal administration of 24 IU of OT or placebo and were tested 45 min later on social skills. Behaviours were carefully monitored and scored using an in-house grid as follows: over the two days before drug administration, on the half-day following administration, and over the subsequent two days. All patients were in a dedicated PWS centre with more than ten years of experience. Patients are regularly admitted to this controlled environment.

Patients with PWS who received a single intranasal administration of OT displayed significantly increased trust in others (P = 0.02) and decreased sadness tendencies (P = 0.02) with less disruptive behaviour (P = 0.03) in the two days following administration than did patients who received placebo. In the half-day following administration, we observed a trend towards less conflict with others (p = 0.07) in the OT group compared with the placebo group. Scores in tests assessing social skills were not significantly different between the two groups.

This study needs to be reproduced and adapted. It nevertheless opens new perspectives for patients with PWS and perhaps other syndromes with behavioural disturbances and obesity.

ClinicalTrials.gov: NCT01038570