The leaders of the cult that the Gra signed the excommunication on almost certainly have schizo typal personality disorders as do many of their followers. People have been able to discern the line between normal thinking, schizo typal thinking and downright schizophrenia.
So the obvious question is what happens when there are real objective phenomena that seem to be above the natural order?
The awareness that there is spiritual thinking that is downright sick is a strong part of the Lithuanian yeshiva experience. and any slight suggestion of this kind of thinking is rigorously excluded.
They are very well aware that there are people that are very religious, but not from a healthy standpoint.
It would be helpful to have a useful measure of such things.
The problem is that this kind of thinking is sanctioned and when people are not outright schizophrenic and have some control they can direct their thinking in socially accepted direction and become the holy man of the community.
The problem that I see is that hanging out with sick people can make one sick --even if he starts out as perfectly normal and healthy. Furthermore following a sick person can make a whole community sick. These are the basic problems I see here.