A 106-person randomized trial found intranasal oxytocin did not improve core social symptoms of autism over placebo, but significantly reduced repetitive behaviors and increased social gaze fixation.
106 participantslargest randomized controlled trial of oxytocin for autism spectrum disorder
What the researchers found
No between-group difference on the primary endpoint (ADOS reciprocity, effect size -0.08, P=.69), but oxytocin significantly reduced repetitive behavior (effect size 0.44, P=.026) and increased gaze fixation on social regions (effect size 0.55, P=.018).
Why it matters
This is the first large-scale, rigorous trial of oxytocin for autism. While the primary endpoint was negative, the significant effects on repetitive behavior and social gaze suggest oxytocin may have specific benefits that could be optimized with different dosing, duration, or combination approaches.
The numbers in context
106 participants; 48 IU/day intranasal oxytocin; 6-week duration; no significant difference on primary social reciprocity outcome.
How the study worked
Randomized, parallel-group, multicenter, placebo-controlled, double-blind trial in Japan. 106 ASD adults (18-48 y.o.) received 6 weeks of intranasal oxytocin (48 IU/day) or placebo. Measured ADOS scores and eye-tracking gaze patterns.
Who was studied
Adults aged 18-48 with autism spectrum disorder in Japan
What this study cannot tell us
Strong placebo response on primary endpoint may have masked real effects. 6-week duration may be too short. Dose of 48 IU/day may not be optimal. Only adult males with high-functioning ASD were included, limiting generalizability.
How to read the evidence
High-quality RCT with proper blinding and multicenter design. Negative primary outcome but significant secondary findings provide nuanced evidence.
When this study was published
Published in 2020. Oxytocin for ASD remains an active research area with ongoing trials exploring different approaches.
The bigger picture
Small studies had generated enthusiasm about oxytocin for autism, but this well-designed trial tempers expectations for broad social symptom improvement. The specific benefits for repetitive behavior and social gaze may guide future research toward more targeted applications or combination therapies.
Questions still open
- Would longer treatment duration or higher doses of oxytocin produce more robust social improvements?
- Could oxytocin combined with behavioral therapy enhance social outcomes beyond either alone?
- Do the benefits for repetitive behaviors and social gaze translate to meaningful improvements in daily functioning?
Common questions
Why might oxytocin help with autism?
Why did both groups improve?
Read the original research
Effect of intranasal oxytocin on the core social symptoms of autism spectrum disorder: a randomized clinical trial.
Molecular psychiatry, 25(8), 1849-1858
Citation
Yamasue, Hidenori; Okada, Takashi; Munesue, Toshio; Kuroda, Miho; Fujioka, Toru; Uno, Yota; Matsumoto, Kaori; Kuwabara, Hitoshi; Mori, Daisuke; Okamoto, Yuko; Yoshimura, Yuko; Kawakubo, Yuki; Arioka, Yuko; Kojima, Masaki; Yuhi, Teruko; Owada, Keiho; Yassin, Walid; Kushima, Itaru; Benner, Seico; Ogawa, Nanayo; Eriguchi, Yosuke; Kawano, Naoko; Uemura, Yukari; Yamamoto, Maeri; Kano, Yukiko; Kasai, Kiyoto; Higashida, Haruhiro; Ozaki, Norio; Kosaka, Hirotaka. (2020). Effect of intranasal oxytocin on the core social symptoms of autism spectrum disorder: a randomized clinical trial.. Molecular psychiatry, 25(8), 1849-1858. https://doi.org/10.1038/s41380-018-0097-2