A really paranoid cynic would say that if any people who don't really have ME are allowed to slip into the ME group, when they are compared to someone from the FMD group (who doesn't have a FMD because they don't exist) then there will be no difference between the two when they are compared.
I'm not a really paranoid cynic. Just sayin'.
Pardon me for quoting myself, but the more I think about this ...
It's also possible that some patients in the FMD group are wrongly diagnosed ME patients (it happens). So that's at least 2 ways that some patients in the ME group can be shown to be just like some patients in the FMD group.
I'm not suggesting that the NIH is intending this result, but when their final report comes out and all the data is released (surely it'll be released?), there's the possibility of others with an interest in such matters interpreting the data in this way. Worse has happened.
ME has been wrongly compared to FMD for 30 years, it should never have happened, and it shouldn't be happening now. The potential linking of ME and FMD should be excluded by a rigourous study design so no-one has to fear it. At the moment all we have are expressions of goodwill from an organisation that seems rather chaotic and doesn't communicate well. Has there been a sensible explanation for why the FMD group is included yet?
Quite apart from the excellent point made above about the potential for continued abuse of those accused of FMD.