It never ceases to amaze me how easily the medical professionals fall back on "conversion disorder" when they don't know the answer to a problem. They seem to think that they are omniscient -- if they don't know about it, it doesn't exist. "I don't understand it, so you're making it up (consciously or unconsciously)." They accept biopsychosocial explanations with much less supportive evidence than they demand from pure physiological explanations. I continuously have to remind myself that doctors are not scientists/researchers, they are glorified technicians. They don't necessarily have the training in or understanding of the scientific process or the methods for drawing sound scientific conclusions.
You'd think they'd have learned from their failures in originally diagnosing MS as hysterical paralysis and ulcers as a stress-related disorder. No doubt there are additional conditions they've misdiagnosed this way, much to the detriment of the patient population.
I have a lot of respect for many doctors -- the ones that think, the ones that use scientific reasoning. We have a number of those helping us with ME/CFS. Many have sacrificed a great deal for the benefit of their patients. The majority of doctors, however --especially GPs -- get so caught up in egotism and group-think that they do more harm than good.
I don't know what is happening with these girls in LeRoy. What I am convinced of is that they leaped to the easy "mass hysteria" aka conversion disorder much too soon in the process. Absence of evidence is not evidence of absence. Keep looking. Don't use some cop-out save-face explanation that lets you give up because solving the problem is too hard.