Expert Dr John Butler has no doubts Quinn runs a cult.
He said: "People are told to believe he is the great guru. Whatever he says or does, they do.
"All success is attributed to the guru and all failures are swept under the carpet.
"There has also been massive exploitation financially."
Dr Butler, a medical psychologist at King's College, London School of Medicine, added: "People stop relying on their own judgment and they surrender more and more to the guru.
"You are soft-soaped about how everyone is happier and healthier in this group and when you get more involved in it, it gets harder to leave.
"Some give up their jobs to go in to a hare-brained idea that they are going to become entrepreneurs without any experience or business proposition.
"Many become unbalanced because they are so naively positive that they squander money on daft schemes.
"Some leave their marriages shattered because their devotion becomes so complete.
"I have worked with people who have tried to come out of cults and found it very difficult."