Honest question (I don't know the answer): would that matter in every study?
I've variously shared houses and worked closely with people with bipolar disorder, schizophrenia and severe depression, and their symptoms couldn't seriously be confused with ME/CFS. I'm not sure why they'd always have to be excluded, when people with other long term conditions that have fatigue as an element aren't.
I think it is less so about confusing the symptoms and rather ensuring that the result you are obtaining are a result of ME/CFS rather than something else and that will always depend on the study setup.
If you're studying cognitive problems in ME/CFS you want to exclude people with Dementia or MS. If you're studying coagulation you will want to exlude patients that have a known condition that includes problems related to coagulation. If you're studying "effort preference" you might want to exclude certain groups with known psychiatric illnesses. A mouse model transferring autoantibodies of patients to mice might want to exclude patients with a known autoimmune disease.
I think the intramural study may have shown that most studies probably had insufficient exclusionary criteria, so I think a tightening there is very adaquate. It may however mean that we'll end up with many underpowered studies. I think the most obvious solution to this problem is that every ME/CFS patient should have access to a specialist once a year where they can undergo a thorough investigation to rule out problems which might have occured over time, but I don't see anybody tackling this problem.
That might all seem pretty obvious, but I think we've seen that most studies don't adhere to such principles and in the case of Long-Covid, out of the several thousand studies published only less than a handful actually looked at their cohort selection with any rigor at all. Now one might argue that the researchers that are making these mistakes are clearly not bright enough to give us valuable clues to solving ME/CFS or Long-Covid in the first place, so whether or not one now enforces certain principles upon them is anyways irrelevant.
However, there is the additional problem that you might have a strong researcher who is aware of all of these problems, but this researcher cannot get access to any "meaningful" patient data because all of the clinicians he can work with and all the databses that exist are not aware of these problems. So enforcing a set of minimally required conditions in ME/CFS research might force the clinicans to start thinking more clearly. But what exactly such a set of minimally required conditions would look like seems to be the key and I suspect that progress will be rather hard as such criteria will fundamentally depend on the type of study you're conducting. In one study excluding people with a certain condition might for example be rather irrelevant whilst matching to controls by gender or age might be more important. In a study on viral persistence you might want to look at date of last known infection (which of the hundreds of studies on LC viral persistence not a single study has done). So whilst enforcing anything doesn't necessarily seem really fruitful to me, I can definitely see how there is a massive necessity for some form of guideline/code of conduct that is well thought out and is also able to go into more details for specific study setups. Which is essentially what I understand
@Hutan to be saying as well. I wouldn't be surprised if there is an abundance of doctors recruiting patients for ME/CFS studies, who have however never heard of ME/CFS before. I can see a sort of Code of Conduct being especially useful there.
In regards to the specifics that the paper mentions like using DePaul etc I also agree with others that it doesn't seem very well thought out yet.
Generally speaking I think one probably doesn't have to enforce much because smart researchers tend to usually figure these things out and those will then flock together and those that don't, don't matter much, however especially when it comes to Long-Covid research I am not convinced anybody is commited to figuring even the most basic things out. At least it seems that even the smart ones have no problem deluding themselves into thinking they have found a singular "biomarker for Long-Covid" albeit their patient cohort consisting of a heterogeneous set of patients where one suffers from anosmia, one had a stroke, the other had acute lung damage, the other had PICS, the other had 4 weeks of diarrhoea, whilst another had ME/CFS and them not even having any idea about whether they are actually studying "Long-Covid" or what that is even supposed to mean.
