This week, we are joined by Kevin Mitchell, Associate Professor of Genetics and Neuroscience at Trinity College Dublin, who has committed the unforgivable sin of pointing out that an entire academic and media hype cycle might be built on… well, very little actually. His new co-authored paper in Neuron politely dismantles the highly promoted link between the gut microbiome and autism, which turns out to rest on flawed studies, contradictory findings, creative statistics, and a touching faith in mice burying marbles.

Kevin walks us through the joys of observational studies that don’t replicate, mouse experiments that don't make sense, and clinical trials where there is no blinding and no control wing, and shockingly, everyone reports feeling better. Meanwhile, journalists and wellness gurus eagerly report each new “breakthrough”, unburdened by any concerns about the strength of evidence or methodological robustness.

In the end, the microbiome–autism connection looks less like a sturdy scientific stool and more like three damp twigs taped together by optimism and marketing departments.

We finish, naturally, by dragging Matt back out of his panpsychism phase and asking whether consciousness is really fundamental to the universe or just something that happens in podcasters who haven’t slept enough.

Links

• Mitchell, K. J., Dahly, D. L., & Bishop, D. V. (2025). Conceptual and methodological flaws undermine claims of a link between the gut microbiome and autism. Neuron.
• Kevin Mitchell's Website