Overview
- The Neuron opinion by Kevin Mitchell, Dorothy Bishop, Darren Dahly and colleagues argues the gut microbiome does not causally contribute to autism.
- Highly cited studies often used 7–43 participants per group, applied non‑comparable methods and produced inconsistent results that frequently disappear after adjusting for diet or using neurotypical siblings as comparators.
- The authors dismiss mouse work as uninformative for human autism, noting that claimed 'autistic‑like' behaviors in rodents lack relevance and the experiments had methodological and statistical flaws.
- Clinical trials of probiotics or fecal microbiota transplants commonly lacked adequate controls and randomization, with better‑designed studies reporting no meaningful effects.
- The paper urges a halt or far more rigorous, well‑powered research, as Wellcome Leap announces $50 million for new studies and the National Autistic Society says the evidence shows no causal link.