His autopsy, however, revealed that he was misdiagnosed and actually had Lewy body dementia.
Three months later, the autopsy report came in and it was found that Williams did not have Parkinson's disease at all. Instead, he suffered from Lewy body dementia, which is characterized by the destruction of cerebral matter and replaced with structures known as Lewy bodies. The symptoms are closely related to Parkinson's disease. Lewy body dementia was slowly taking away Williams' talents and social skills, which eventually led him to commit suicide.
Lewy body dementia is also similar to Alzheimer's disease. However, while patients with Alzheimer's have trouble creating new memories, patients with Lewy body dementia have issues recalling existing memories.
In Dave Itzkof's biography Robin, he interviews Williams' family, friends, and co-stars to get an inside look at his final days. Documenting his career from his stand-up rifts to his classic and most celebrated films, Itzkof also highlights Williams' conflicting emotions. Itzkof discusses Williams' struggles with addiction, depression, and his diagnosis. Readers have called this biography a "fresh and original look at a man whose work touched so many lives."
Photo source: Robin Williams by michelarouca