One difficulty was the portrayal of his mental illness and trying to find a visual film language for this. As a matter of fact, Nash never had visual hallucinations: Charles Herman (the "roommate"), Marcee Herman and William Parcher (the Defense agent) are a scriptwriter's invention. Sylvia Nasar said that the filmmakers "invented a narrative that, while far from a literal telling, is true to the spirit of Nash's story". Nash spent his years between Princeton and MIT as a consultant for the RAND Corporation in California, but in the film he is portrayed as having worked for the Department of Defense at the Pentagon instead. His handlers, both from faculty and administration, had to introduce him to assistants and strangers. The PBS documentary "A Brilliant Madness" tried to portray his life more accurately.