My ideal scenarios involve speech restriction, forced to wear embarrassing babyish outfits, restrains, only allowed to eat baby food and drink from baby bottles, and obviously thick diapers that only get changed when they're thoroughly soaked.
While it was probably quack medicine, and often dark (tied to beds and forced into diapers, forced regressed living for years on end), the reports describe some deeply intriguing events, including full diapering and use, spanking, adult adoption, breastfeeding, and so on, which is almost impossible to believe. Unfortunately it had a dark ending where there was an accidental death between two men, but the earlier stuff is impossibly intriguing.