I had an aunt who did est back in the day, and my sister did the Landmark Forum. Neither of them acted like a cult member, but they did both (temporarily) lose the ability to relate to the people around them on anything but the respective movements' terms (and more importantly, using the movements' lingo). It's like they were speaking in code. That's what has me going "eek" for Stan.
Re: est, Werner Erhard, etc.
-J