A note for people not familiar with the terminology - "functional connectivity" is a specific technical term that really just means temporal correlation between brain areas, as opposed to "structural connectivity" which refers to the actual neural pathways that are formed between brain areas. If you rephrase the headline as "Serotonin booster leads to increased correlation between activity in different brain areas" i…
The main reason it's not too exciting to me is much simpler. They tested it for 6 days. You can do all sorts of wonderful stuff with a drug for a few days. But for most drugs, the effects simply cease if you keep taking it due to tolerance. And there doesn't seem to be a huge amount of leeway to up the dose either because it's a laxative.
It would be nice to see a longer term study. And no people shouldn't be buying this in IndiaMart but critical analysis of studies isn't just about being as pessimistic as possible.
It's overly pessimistic as it's not constructive. Instead of asking for longer term studies you declare the effect probably won't last.
There are loads of criticisms one could make of the study and wider hypothesis. But as with all criticism it should be constructive where reasonable.