A pilot study of serotonergic modulation after long-term administration of oxytocin in autism spectrum disorder.
Daily oxytocin boosts one brain marker in autistic males, but brings no clear day-to-day gain.
01Research in Context
What this study did
Researchers gave daily oxytocin nose spray to autistic males for eight to ten weeks. They scanned brains before and after to see if serotonin transporters changed.
No control group was used. The team wanted to know if longer oxytocin use alters brain chemistry.
What they found
Serotonin transporter binding rose in the left frontal cortex after the spray period. Symptom scores, however, stayed flat.
In short, the brain marker moved, but daily life did not.
How this fits with other research
Moerkerke et al. (2024) extends this work. They ran a four-week RCT with autistic kids and found no fMRI face-processing gain under oxytocin. Together, the two studies show brain changes do not equal behavior changes.
Laposa et al. (2017) used the same pre-post design with no drug. Caregivers still reported big gains on rating scales after eight weeks. This warns us that caregiver reports alone can mislead when no control group exists.
Bao et al. (2017) reviewed all oxytocin-ASD papers the same year. They flagged weak methods and mixed results. The pilot fits right into that cautious picture.
Why it matters
Oxytocin can nudge serotonin machinery, but that nudge does not yet help clients talk, play, or connect. Keep behavior plans front and center. If a family asks about oxytocin, share that brain scans look better, yet daily skills have not moved in trials. Document your own data before and after any drug to see real change.
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02At a glance
03Original abstract
Oxytocin (OT) and the serotonergic system putatively play important roles in autism spectrum disorder (ASD) etiology and symptoms, but no direct neurobiological evidence exists for long-term OT administration effects on the brain's serotonergic system. This pilot study examined 10 male participants with ASD who were administered OT intranasally for 8-10 weeks in an open-label, single-arm, nonrandomized, and uncontrolled manner. Positron emission tomography (PET) with a radiotracer (11 C)-3-amino-4-(2-[(dimethylamino)methyl]phenylthio)benzonitrile (11 C-DASB) was used before and after OT treatment. The binding potential of serotonin transporter (11 C-DASB BPND ) was then estimated. The main outcome measures were changes in 11 C-DASB BPND and their correlation with changes in symptoms. ASD participants showed significantly elevated 11 C-DASB BPND in the left inferior frontal gyrus extending to the left middle frontal gyrus. No significant correlation was found between the change in any clinical symptom and the change in 11 C-DASB BPND . This report of a pilot study is the first describing long-term effects of OT on the brain's serotonin system in ASD. Additional randomized controlled studies must be conducted to confirm whether activation of the serotonergic system contributes to the prosocial effect of OT in people with ASD. Autism Res 2017, 10: 821-828. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.
Autism research : official journal of the International Society for Autism Research, 2017 · doi:10.1002/aur.1761