Autism spectrum disorder (ASD) is a group of life-long neurodevelopmental conditions characterized by impairments in social communication and by the presence of restricted interests or repetitive behaviors. Several genetic, biological, and psychosocial mechanisms seem to play a role in the etiopathogenesis of this complex condition. Preclinical models have shown a potential role of oxytocin (OT), a peptide involved in a complex range of behaviors, including those related to social interaction. Therefore, it has been hypothesized that OT levels may be decreased in autistic people.

To compare the levels of peripheral OT in autistic people vs neurotypical controls.

We performed a systematic literature search up to December 2020 according to PRISMA guidelines. Final inclusion was based on the following criteria: (1) Participants: individuals of any age diagnosed with ASD; (2) Controls: neurotypical subjects; (3) Outcome: OT levels, either in saliva, serum, or plasma; (4) Study design: case-control. Meta-analyses are ongoing.

We finally included 21 papers published between 1998 and 2020, of which one recruited adult participants. Fifteen studies measured OT levels in plasma, 4 in saliva, and 2 in serum. Preliminary meta-analyses on 10 studies showed that peripheral OT levels in autistic individuals are reduced compared to neurotypical controls, with sex differences.

Our preliminary findings show that peripheral OT might represent a potential biomarker for ASD. Future well-conducted case-control studies with a detailed phenotypical characterization of samples are needed to understand the role of OT deficits in specific subgroups.

No significant relationships.