I often read that she had violent mood swings, but nothing more specific than that. Was it known at the time of there was something specifically handicapping her?
Per David Nasaw's biography of Joseph Kennedy, she had a learning disability from a young age but an official diagnosis eluded the Kennedys. Rosemary attended "public school, a private boarding school for "slow" children, homeschooling, a Sacred Heart convent, but nothing has quite worked out." (222)
After sending her to a private girls' school (Miss Hourigan's Residence School) where she had a private tutor, she had limited success, but was eventually asked to return to the convent where she had been educated previously. Per the school's dean, Miss Hourigan: "...I realized that Rosemary needed continual protection or supervision. This entailed a constant checking, which was a responsibility that could never be let down."
Rosemary needed a tremendous amount of attention and suffered from learning disabilities that were never completely diagnosed. Joe and Rose Kennedy tried a variety of treatments ("gland therapy" from Dr. Charles Lawrence, the chief endocrinologist at the New England Medical Center, a personalized curriculum based on the works of John Dewey recommended by Dr. Walter Dearborn, a Harvard clinical psychologist, etc.). The most important mention of her angry behavior stems from the interruption of her normal routine and care by World War 2: Rose Kennedy wrote in her memoirs that "In the yer or so following her return from England, disquieting symptoms began to develop. Not only was there a noticeable retrogression in the mental skills she had worked so hard to attain, but her customary good nature gave way increasingly to tension and irritability. She was upset easily and unpredictable. Some of these upsets became tantrums, or rages, during which she broke things or hit out at people. Since she was quite strong, her blows were hard. Also there were convulsive episodes".(532)
The lobotomy was the final in a series of treatments dedicated towards allowing Rosemary to live a normal life. Joseph Kennedy met with Dr. Walter Freeman in Fall of 1941, who was the chair of the Department of Neurology at the George Washington University Medical School and had been performing the procedure for five years. Rosemary received the surgery on November 12th and was stunted for the rest of her life.
Follow-up: to what extent did any diagnosis that was suggested for her conform to diagnostic standards for the time? What kind of treatment, if any, might the doctors available to the average citizen have been in favor of for a patient like her?