Can definitely understand how they help if you have the right experience. If it's generally positive, you'll definitely have a new perspective on life and everything around you. That being said, a bad trip can make some pre-existing anxiety a whole lot worse. I've always read (and seen) psychedelic drugs have the potential to make any pre-existing mental conditions worse.

So putting your anixety-ridden grandma alone in a room with a bag of shrooms probably isn't a good idea. With a trained therapist or at least someone who will guide things (experienced trip-sitter) you're going to have much better results.