Even with just the term 'mcs' _ I don't know how useful that is. I seem to respond badly to some soaps and washing powders, and lots of scents give me a head-ache now, but in the popular imagination the 'MCS' term seems really associated with patients following advice from dodgy sources or claiming to be certain that they cannot be near chemicals that they do not seem to respond to under blinded conditions.
I read some of the studies trying to work out what was going on.
Honestly I can’t figure out why the idea of MCS has such a bad rap because it’s well known that people with other diseases like asthma or migraine or seizure disorders often respond poorly to environmental substances, and migraine, for example, is not well funded or well studied.
Anyway back to the studies, it didn’t look to me in the papers I looked at, like they were studying people who were diagnosed with MCS (is there a criteria?) or that this was necessarily something that affected their lives.
It seemed like they had possibly a convenience sample which they had screened with irrelevant questions (“are you concerned about synthetic chemicals?” Something like that, when anyone who knows anything about it understands that this isn’t a worry about “synthetic chemicals” because one could easily react to potpourri, basil oil, eucalyptus, wool, latex, or any number of natural substances).
So of course if they just grabbed random people that were “worried about how many chemicals are being used in the modern world”, they obviously weren’t going to get necessarily people with MCS.
With that kind of selection criteria, it’s not surprising they failed to show any results demonstrating sensitivities.
Maybe it’s just a game to some people who publish papers.