Gastrointestinal, Behaviour and Anxiety Outcomes in Autistic Children Following an Open Label, Randomised Pilot Study of Synbiotics vs Synbiotics and Gut-Directed Hypnotherapy.

The trial was open label and had no control group, so placebo effects, natural symptom fluctuation, or continued standard care could explain the within-group improvements. It was a pilot with a small analysed sample: 36 randomised, 31 analysed at 12 weeks, and 25 at 24 weeks, and it did not reach the target of 40. Randomisation did not balance sex or baseline anxiety between groups; the synbiotic group had more males and the combined group had higher baseline anxiety, and analyses adjusted for these. Outcomes were parent-reported, and parents knew which treatment their child received, which may introduce measurement bias. Diet was not tracked, although parents were asked not to change it and reported no changes during monitoring. Both arms received the synbiotic, so the study cannot determine whether the synbiotic itself is better than no treatment, and it cannot separate the effects of synbiotic, gut-directed hypnotherapy and standard care. The microbiome analyses were exploratory, involved many uncorrected tests, and showed inconsistent taxonomic changes, so they cannot be treated as clinical outcomes.

The paper states that The University of Queensland funded the study. It does not provide a separate author conflict-of-interest declaration in the supplied text.

Do not conclude that synbiotic plus gut-directed hypnotherapy is better than synbiotic alone for gastrointestinal symptoms, behaviour or anxiety. The primary between-group comparison was not significant, and both groups received the synbiotic. All participants continued standard care, so the within-group improvements cannot establish that the treatments caused them.