Anavex tested the microbiota of 16 long term users. They said that those that responded better had more of two important microbiomes. They did not say which came first, the chicken or the egg.
They are doing an extended study to learn more about the gut-brain connection. Nothing wrong with making observations, no baseline is needed but the data is likely to be informative down the road.
As for "proof of it beating placebo". That could be showing up in the current trial after five weeks with better sleep as mitochondria begin to function better.
The problem with most of the medicine on the market to day is the "double blind placebo" process, stat sig, and approval. No research is done into why a certain percentage of patients have side effects, and if the drug is toxic for only a small percentage that's acceptable collateral damage.
The "double blind placebo" system has killed millions.
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