Sybil's influence on society cannot be overstated. Aside from the massive amount of money the disorder made for Hollywood, hospitals opened up entire wings to treat a sudden influx of multiple personality patients. Some patients came to doctors believing the disorder put a name to what they already felt, some wanted to make a buck on the book deal, some wanted attention and care. Not all the interest came from the patient's end. Unscrupulous doctors went on the hunt for patients. Everyone wanted a multiple personality case to call their own.
Then came the debunking of the book and the bane of any cultural phenomenon: lawsuits. In the early 1990s patients started suing doctors for using drugs and threats of abandonment to coerce more personalities into showing up for their sessions. Then patients, some of whom had spent years in hospitals, started suing for misdiagnoses. Money and fame went out the door and bankruptcy and infamy strolled in. No one wanted to diagnose anyone with multiple personalities anymore.
So, of course, they changed the name, to dissociative identity disorder. Sigh.