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Opinion

Negative result

by  /  30 August 2013

Oxytocin has myriad complex effects on behavior, many of which suggest that it could be a treatment for autism.

In both rodents and people, for example, the hormone has been shown to increase trust, bonding, eye contact and emotion recognition, and alleviate social anxiety and repetitive behaviors. Despite its potentially harmful effects, these studies have placed oxytocin as a front-runner among candidate treatments for autism.

A new study, published 26 July in the Journal of Autism and Developmental Disorders, finds that although oxytocin is well established as the ‘social hormone’ in the popular imagination, it has no effect on children with autism.

If that’s true, parents of children with autism should take note: Many parents are already administering oxytocin to their children even though no rigorous trials have yet established its effectiveness.

The new study enrolled 38 children with autism — compared with 16 in the previous largest study — and compared the drug with placebo. Both those factors already make it a better study than most on this topic. The researchers also went further than previous studies did, which mainly treated participants immediately prior to an experimental task.

Because oxytocin may increase sensitivity to social cues, researchers have suggested that it heightens children’s awareness during behavioral interventions. The new study put this theory to the test.  

The boys in the study, aged 7 to 16 years, stayed at the clinic with their parents for five days. They took oxytocin or placebo every morning and, along with their parents and a therapist, watched interactive videos designed to teach communication skills.

The families then spent time in a structured interaction, which the researchers videotaped. Each session was divided into ten minutes of free-play time, ten minutes discussing an emotional past experience and two minutes in which the parents complimented their children.

The researchers compared the children’s scores on social skills, repetitive behaviors and emotion recognition from three to six months prior to treatment, immediately following treatment and three months later.

Over the course of the study, the treatment and placebo groups both improved on these measures, with no significant difference between the two.

Given oxytocin’s reputation, the researchers were so surprised by these results that they considered the possibility that they had mixed up the placebo and oxytocin sprays. A check by chemists at the university confirmed that there was no mix-up: Oxytocin really had no effect on these skills.

Most of the evidence linking oxytocin to autism is correlative. People with autism are more likely than controls to carry a common variant in the oxytocin receptor gene, for example. And there are a handful of individuals who have autism and a deletion that overlaps with this gene.

Oxytocin treatment may work in these individuals with autism, but not in others, which could explain discrepancies between studies, the researchers suggest.

Either way, the study is one more note of caution when it comes to this so-called ‘trust hormone.’ Without better proof of its benefits, it is too soon to trust that it is worth the risks.