A Comprehensive Review Unveils Limited Evidence for Complementary and Alternative Treatments in Autism Spectrum Disorder
In the ever-evolving landscape of autism research, a new landmark umbrella review has taken a rigorous and comprehensive approach to evaluate the efficacy and safety of complementary, alternative, and integrative medicines (CAIMs) for treating autism spectrum disorder (ASD). Conducted by an international collaboration involving Paris Nanterre University, Paris Cité University, and the University of Southampton, this exhaustive meta-analysis synthesis consolidates findings from 248 meta-analyses encompassing over 200 clinical trials and involving more than 10,000 participants. Published in Nature Human Behaviour on August 28, 2025, the study provides an unprecedented assessment of the current evidence base for 19 different CAIM interventions, including but not limited to animal-assisted therapy, acupuncture, herbal supplements, music therapy, probiotics, and Vitamin D.
Autism spectrum disorder is a neurodevelopmental condition characterized by difficulties in social communication, sensory processing challenges, and repetitive behaviors. For many autistic individuals and their families, these challenges impact everyday functioning and quality of life profoundly. It is estimated that up to 90% of autistic individuals have tried at least one form of CAIM during their lifetime, demonstrating widespread use despite uncertain evidence supporting these therapies. CAIMs often appeal due to their perceived safety profiles and accessibility, but their clinical utility remains a controversial and under-studied area, which this new umbrella review aims to clarify.
The methodology of the study is noteworthy for its breadth and depth. Umbrella reviews aggregate data from meta-analyses themselves, thereby providing what is essentially a “big picture” viewpoint across a large volume of research. Instead of focusing on isolated clinical trials, which can produce contradictory or preliminary findings, this approach synthesizes existing secondary research to appraise the overall quality and reliability of the evidence. This allows for more robust conclusions about both the efficacy and the safety profiles of different CAIMs in the context of autism care.
One of the most striking findings from this review is the scarcity of strong, high-quality evidence supporting the effectiveness of CAIMs for ASD. While some individual studies suggested potential benefits, when combined and assessed comprehensively, the majority of CAIMs failed to meet stringent scientific criteria for clinical efficacy. This lack of conclusive benefit highlights a major gap between patient and caregiver expectations and what is empirically supported. Moreover, the review uncovered a pervasive deficit in safety evaluations: fewer than half of the CAIM interventions had any substantive data on acceptability, tolerability, or adverse effects. This finding is particularly concerning because the assumption that “natural” or “alternative” equates to safe is demonstrably flawed, particularly in vulnerable populations such as children with developmental disorders.
The spectrum of CAIMs evaluated ranged widely in modality and purported mechanism of action. Animal-assisted interventions, for instance, aim to improve social engagement and reduce anxiety through structured interaction with therapy animals. Acupuncture and traditional Chinese medicine seek to balance neurophysiological processes through stimulation of specific points or herbal formulations, with theorized neurochemical effects. Nutritional supplements like probiotics and Vitamin D have been investigated for potential roles in modulating gut-brain axis pathways or supporting neuroimmune function. Music therapy is thought to enhance communication and emotional regulation. However, this review emphasizes that despite biological plausibility, current evidence is insufficient or low in methodological quality to advocate for their standardized clinical use.
Safety concerns were inadequately addressed across many studies, representing a troubling oversight in the field. Reliable evaluation of adverse events, both short- and long-term, is critical to underpinning responsible clinical recommendations. The lack of systematic reporting creates uncertainty for clinicians and families weighing the risks and benefits of CAIMs. Without rigorous pharmacovigilance or adverse effect monitoring frameworks analogous to those for conventional pharmacological treatments, CAIMs risk being utilized without fully understanding potential harms, interactions, or contraindications.
To address the complexities surrounding treatment selection and information dissemination, the research team has developed an innovative online platform designed to democratize access to the evidence they synthesized. This freely accessible tool aims to empower autistic individuals, families, and healthcare providers by presenting clear, up-to-date summaries of the strength and quality of research on each CAIM intervention. By fostering informed decision-making based on comprehensive and transparent data, the platform aspires to improve clinical outcomes and patient satisfaction.
Professor Richard Delorme, Head of the Child and Adolescent Psychiatry Unit at Robert Debré Hospital in Paris and a contributor to the study, remarked on the challenges faced by families and adults with autism: the lure of alternative treatments is understandable given the unmet clinical needs and desire for fewer side effects than conventional medications. Nonetheless, he cautioned against adopting therapies without solid evidence of benefit, underscoring the importance of well-designed randomized controlled trials to establish efficacy and safety before clinical uptake.
Co-senior author Professor Samuele Cortese from the University of Southampton emphasized that relying on isolated studies can be misleading and potentially harmful. The umbrella review approach illustrates the necessity of synthesizing broad evidence landscapes and critically appraising the robustness of underlying data. This macro-level analysis mitigates the risk of overgeneralizing from small, underpowered, or biased studies that may create false hope or distract from more effective interventions.
The significance of this comprehensive evaluation extends beyond clinical guidance—it also highlights key research gaps and priorities for the scientific community. Future investigations must standardize outcome measures, enhance trial design rigor, explicitly monitor adverse events, and prioritize replication studies to build a reliable evidence base. Furthermore, examining biological mechanisms and patient heterogeneity in response to CAIMs could unravel why some interventions show promise in select populations, fostering personalized treatment approaches.
In conclusion, the umbrella review represents a critical step forward in clarifying the role of complementary, alternative, and integrative medicines in autism. It calls for cautious interpretation of existing data, prioritizes safety alongside efficacy, and advocates for collaborative decision-making supported by accessible evidence tools. As autism prevalence continues to rise and the demand for therapeutic options grows, research such as this underscores the imperative for rigorous scientific validation to guide families and clinicians toward truly effective and safe treatment modalities.
Subject of Research: People
Article Title: Complementary, alternative and integrative medicine for autism: an umbrella review and online platform
News Publication Date: 28-Aug-2025
Web References:
DOI: 10.1038/s41562-025-02256-9
University of Southampton: www.southampton.ac.uk
Keywords: Autism; Alternative medicine; Traditional Chinese medicine
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