The largest quantitative analysis of studies on complementary and alternative treatments for autism has found no convincing evidence of their effectiveness. Additionally, safety concerns are often overlooked, and many methods have never undergone thorough risk assessment.

The research was conducted by scientists from the University of Paris-Nanterre, Paris Cité University, and the University of Southampton, and published in the journal Nature Human Behaviour. The study analyzed 248 meta-analyses based on the results of 200 clinical trials involving more than 10,000 participants.

Which methods were studied

The authors focused on complementary, alternative, and integrative medicine methods (CAIM) used for autism treatment. In total, 19 different types of interventions were considered, including animal-assisted therapy, acupuncture, herbal medicine, music therapy, probiotics, and vitamin D supplementation. During the study, the team also developed an online platform to help the public more easily access scientific data on various CAIM approaches.

Why alternative methods are popular

People with autism often face challenges in communication, understanding others’ thoughts and emotions, managing sensory overload, adapting to new environments, and repetitive behaviors. These features can significantly impact daily life and overall well-being, which is why interest in alternative treatments is so high. Studies show that up to 90% of people with autism have tried at least one CAIM method.

Professor Richard Delorme, head of the Department of Child and Adolescent Psychiatry at Robert Debré Hospital in Paris, notes: “Many parents of children with autism, as well as adults with autism, turn to complementary and alternative methods hoping they will help without unwanted side effects. However, it is essential to carefully consider data from rigorous randomized studies before drawing conclusions about the appropriateness of these methods.”

How the evidence was evaluated

To cover the full scope of existing research, the team conducted an umbrella review—a method that combines the results of multiple meta-analyses to provide an overall picture. Associate Professor Corentin Gosling from the University of Paris-Nanterre, the study’s lead author, explains: “Instead of looking at individual trials, we analyzed all available meta-analyses, which themselves combine many studies. This allowed us to assess the entire body of evidence for different methods. We also developed a free and user-friendly online platform, which we will continue to test. Ultimately, we hope this tool will help people with autism and professionals choose the best treatment together.”

Weak evidence and limited safety data

Although a small number of methods showed potential benefits, most relied on weak or low-quality evidence, making the observed effects unreliable. The researchers also expressed concern about safety issues: less than half of the methods were evaluated for acceptability, tolerability, or possible side effects.

Professor Samuele Cortese, NIHR Professor at the University of Southampton and co-author of the study, emphasizes the importance of a comprehensive approach: “This research shows that when assessing the effectiveness of a method, one cannot rely on a single study. It is necessary to consider all available data and their quality. Drawing conclusions based on one low-quality study can be misleading.”

The study “Complementary, alternative, and integrative medicine for autism: an umbrella review and online platform” was published in Nature Human Behaviour and is available online. The online platform can be found at: https://ebiact-database.com. The work was funded by the French National Research Agency (ANR).