Randomized, double-blind, placebo-controlled oxytocin trial in children with Prader-Willi syndrome.
Effects on social behaviour.

Patients with PWS have behavioural problems and are at risk for morbid obesity.
Several studies demonstrated hypothalamic and oxytocinergic dysfunction in
patients with PWS. The number of oxytocin-expressing neurons in the PVN of
patients with PWS is significantly decreased with 42%. Recent studies in humans
found positive effects of oxytocin on social behaviour and weight balance. The
oxytocin system is a promising target for therapeutic intervention, especially
in aberration in social function and obesity control. A pilot study with
intranasal oxytocin adminstration in adults with PWS showed positive effects on
social behaviour, as did our previous study in children with PWS aged 6 to 11
years.

To evaluate the effects of intranasal oxytocin versus placebo on social
behaviour and also on eating behaviour in children with PWS.

A randomized, double-blind, placebo-controlled cross-over trial: twice daily
intranasal oxytocin or placebo for 3 months each, with a wash-out of 1 month
between cross-over.

Twice daily placebo and twice daily oxytocin intranasal administration in
cross-over design.

Burden: administration of intranasal oxytocin or placebo twice daily during a
total of 6 months. Six hospital visits in 7 months with questionnaires, four of
these visits will include a blood sample, DXA-scan and psychological test. A
short diary about social and eating behaviour and food intake has to be filled
out by parents daily during 5 days prior to each visit.
Risks: based on literature and our previous experience, we do not expect any
side effects or adverse events during oxytocin administration. Patients and
their parents are highly motivated to participate in this study because of the
major impact of social problems and hyperphagia on the daily life of patients
and their family.