There are many crazy lunes who run around believing they've holy spirit, but then, there are crazy people in general who believe or do not believe in any number of things. Of course, I am suspicious of anybody who claims divine revelation. Pentecostals and other fundamentalists have made a mockery of Christianity, as has the Society.
But wisdom is proven righteous by its works. Is the person more balanced or extreme? More loving or judgemental? More reasonable or less? These are a good indicators.