Prader-Willi Syndrome (PWS) is characterised by symptoms such as obsessions, overeating, rage attacks, skin picking, irregular sleep breathing and temperature control, and impairments in learning and understanding social cues. Evidence from brain studies suggest that such symptoms maybe related to a deficiency of oxytocin, a natural occurring hormone derived in the hypothalamus. This study aims to investigate the efficacy of oxytocin nasal spray on improving behaviour and physical health in PWS.