The most comprehensive quantitative review of research into complementary and alternative treatments for autism has found no strong evidence to support their use, and that the safety of these treatments was rarely assessed.
A new study from Paris Nanterre University, Paris Cité University and the University of Southampton, published in Nature Human Behaviour, assessed 248 meta-analyses, including 200 clinical trials involving over 10,000 participants.
Researchers were investigating the efficacy and safety of complementary, alternative and integrative medicines (CAIMs) to treat autism. They looked at 19 types of treatment, including animal-assisted interventions, acupuncture, herbal medicine, music therapy, probiotics and Vitamin D.
The team also created an online platform to make it easier for people to see the evidence they generated on different CAIMS.
Autistic people can find it hard to communicate, understand how people think or feel, be overwhelmed by sensory information, become anxious in unfamiliar surroundings and carry out repetitive behaviors.
All of this can interfere with their quality of life, and up to 90% report having used CAIMs at least once in their lifetime.
"Many parents of autistic children, as well as autistic adults, turn to complementary and alternative medicines hoping they may help without unwanted side effects," says Professor Richard Delorme, Head of the Child and Adolescent Psychiatry Unit at Robert Debré Hospital in Paris.
"However, it is necessary to carefully consider evidence from rigorous randomized trials before concluding that these treatments should be tried."
Researchers carried out an umbrella review -- a type of study that pulls together evidence to give an overall "big picture" summary.
Dr. Corentin Gosling, Associate Professor at the Paris Nanterre University and first author of the study, explains, "Rather than looking at individual trials, we reviewed all the available meta-analyses, which are a compilation of many trials. This allowed us to evaluate the full body of evidence across different treatments.
"Importantly, we also developed a free and easy-to-use online platform, which we will continue to test. Ultimately, we hope this tool will support autistic people and practitioners in choosing together the best treatment."
While some treatments showed potential, most studies were supported by weak or poor-quality evidence, so the effects are not reliable. Concerningly, safety assessments were missing for most treatments, with less than half of CAIMs having had any evaluation of the acceptability, tolerability or adverse events.
Professor Samuele Cortese, NIHR Research Professor at the University of Southampton and co-senior author, concluded, "This study shows that when people want to know whether a treatment is effective, they shouldn't just look at one single study. It's essential to consider all the available evidence and how good that evidence is. Drawing conclusions from one low-quality study can be misleading."