When the movie A Beautiful Mind came out in 2001, there were many complaints about its accuracy. Most of the complaints had to do with omitting embarrassing details of his life. But many of those details were just unverified rumors that did not belong in the movie anyway. I found it odd that this mostly-accurate movie was so criticized, when other supposedly-factual movies like the recent 21 are gross fabrications that are horribly misleading in every scene.
The biggest fiction in the movie was the display of visual hallunications, when Nash actually heard non-visual voices.
But here is a distortion that is deliberately misleading. A Beautiful Mind shows the hero recovering from his mental illness, and saying, "I take the newer medications." In fact he hated the forced psychiatric drugs that he had to take in the 1960s, and he never took any after that. The director said that he wanted to promote psychiatric drugs. What most people don't know is that the drugs are really not very effective.