I have experienced this with two different practitioners. The first was a LMFT trained in it who helped me process a date rape experience from a Christian perspective, inviting Jesus into the situation and processing what he would say to me as that frightened, traumatized teen-ager. It was pretty effective. Years later, a chiropractor tried it to process my son's tragic death and it did not seem to be as helpful. I'm not sure he had the same level of training. So, yes, I do believe the effectiveness has a lot to do with the training and expertise of the facilitator.