In November 1941, Joe Kennedy arranged to have a lobotomy performed on Rosemary. She had become "difficult" to handle and he was assured a lobotomy would "calm" her. It was immediately clear that the operation had drastically failed, though by Joe's expectations it was a complete success ----Rosemary had lost most of her ability to walk or talk.
She was an adult, 23 at the time, without an advocate --- not even her mother who wasn't told of the surgery until after it was completed.
Just another evil chapter from a family legacy filled with them.