Effects of oxytocin administration paired with social interaction on stress physiology in children with autism and co-occurring intellectual disability.

Intranasal administration of the neuropeptide oxytocin (OT) is a therapeutic option targeting the impairments in autism spectrum disorder (ASD). While initial proof-of concept studies have shown improved functioning after multiple-dose OT treatment in children with ASD (<12 years), confirmatory studies are needed in larger cohorts and to study long-term effects. Moreover, most of the studies excluded autistic individuals with comorbid intellectual disability (ID), who make up to 40% of people with ASD, and who often display more severe impairments. With the current project, we propose a large-scale randomized, double-blind, placebo-controlled trial testing the effects of multiple-dose OT treatment (four weeks of two daily intranasal administrations; total of 24 IU/day) in a confirmatory sample of 100 boys with ASD (8-12 years) on core autism symptoms (social functioning, repetitive behaviors) and several secondary outcomes (e.g. attachment, stress, anxiety). This study will be the first to include boys with a comorbid ID. It will also be the first to explore longterm effects of OT in these groups. Thus far, long-term retention of OT effects has only been reported in adult men with ASD. In summary, this confirmatory trial will provide important insights into treatment effects in children with ASD and comorbid ID as well as possible variations depending on person-dependent factors (e.g. endogenous OT levels) as well as into the long-term effects of OT treatment. These insights are essential for the translation and further development of OT-based therapies for ASD.