13. John Nash attended the Carnegie Institute of Technology on a full scholarship. One of his professors was so impressed with him that he wrote him a letter of recommendation for Princeton that contained only one line; "This man is a genius."
14. According to a 2001 Entertainment Weekly article on this film, the filmmakers originally wanted to mention John Nash's homosexuality, but they feared the film would make the wrong connection between homosexuality and schizophrenia, so they abandoned it. This connection, according to the article, was based on several now-discredited psychological studies that first appeared in the late 1950s.
15. During filming, Ron Howard decided that Nash's delusions should always be introduced first audibly and then visually. This provides a clue for the audience and establishes the delusions from Nash's point of view.
16. The film was shot 90% chronologically.
17. Producer Brian Grazer won the rights to the project after John Nash and Alicia Nash chose him over competitor Scott Rudin; the Nash's had long resisted having a film made of their story.