Rosemary Kennedy was described as easygoing as a child, but as a teenager, the maturing Kennedy became increasingly assertive in her personality. She was reportedly subject to violent mood swings. Some observers have since attributed this behavior to her difficulties in keeping up with siblings who were expected to perform to high standards, as well as the hormonal surges associated with puberty. In any case, the family had difficulty dealing with the often-stormy Rosemary, who had begun to sneak out at night from the convent where she was educated and cared for.
In 1941, when Rosemary was 23, doctors told her father that a new neurosurgical procedure, lobotomy, would help calm her mood swings and sometimes-violent outbursts. Joseph P. Kennedy decided that Rosemary should have the lobotomy performed, but did not inform Rose until afterwards. (adapted from wikipedia)
Image from everything kennedy tumblr (link)
Rosemary was said to have been considered retarded by members of her family but that assessment has been widely disputed by subsequent analysts. Some concluded that Rosemary may not have been as brilliant as other members of her family but she was a fully functioning person, kept a diary and had an active social life. In 1941, when Rosemary was 23, her father Joseph Kennedy was told by her doctors that a new procedure would help calm her mood swings that the family found difficult to handle at home. Her father gave permission for the prefrontal lobotomy to be performed by Walter Freeman and James Watts. After the surgery Rosemary was reduced to an infantile mentality that left her incontinent and staring blankly at walls for hours. Her verbal skills were reduced to unintelligible babble. In 1949, Rosemary moved to an institution and was visited on regular occasions by her sister Eunice Kennedy Shriver who became the founder of the Special Olympics. -reblogged from listverse.com –(link)
The Kennedy Children, 1928. (L-R) Jean, Bobby, Patricia, Eunice, Kathleen, Rosemary, Jack, Joe Jr. Hyannis Port, 1928. Photograph in the John F. Kennedy Presidential Library and Museum, Boston.
John F. Kennedy Library Foundation