Why don't John Nash's delusional persons age?
TL;DR: because of his desease, his brain (kind of) "doesn't" want/make them age, so they don't. He doesn't connect the lenght of his interactions with these persons (Charles, William and Marcee) with the time elapsed in his own life. That's a thing (symptom?) he may not realize at first sight.
I suspect the reason is that Nash is aware of his disease and if he didn't know about it he would see them aged.
That's quite the opposite actually. He becomes aware of his condition when he realizes that they don't age. This is particularly well worded in this analysis by Maria Gaglio in 2019: Accuracies and Inaccuracies: Analysis of the portrayal of Schizophrenia in the major motion picture 'A Beautiful Mind'
Nash, throughout his struggle with Schizophrenia, was still able to have intelligent thoughts. Being so smart, Nash was able to introspectively assess the situation he was in and come to the realization that a lot of the things he had been doing and the people he had been talking to were part of the symptoms of schizophrenia. Nash is able to make the connection that Marcee, Charles’ niece (delusion), is not real, because over time she does not age.
A connection like this something that many suffering from Schizophrenia struggle to make. The movie makes it seem like it is quite easy for someone to make this connection like Nash did. People with Schizophrenia experience these delusions and hallucinations for a large part of their lives, and when they are told that something that seems so real to them is not, it creates dissonance (Saha, 2017). Recognizing that they themselves are sick is not something that comes easily.
What John Nash hears and sees are just normal life's events for him (in the quote from NIH below, the emphasis is mine). These bullet-points and paragraphs are excerpts from Recognizing Schizophrenia - U.S. Department of Health and Human Service. You can easily see how these character traits fit the ones of John Nash played by Russell Crowe.
- Hallucinations (seeing, hearing or feeling things that no one else can)
- Delusions (believing things that aren’t true)
- Thinking-related problems that make it hard to have a job or take care of yourself
- Lack of facial expression
- Talking very little or in a dull voice
- Inability to follow through with planned activities
- Trouble focusing or paying attention
What would it be like to hear voices or see people or things that aren’t really there? How would you feel if people seemed out to harm you, and you weren’t sure who to trust? Would you recognize that something was wrong?
Unfortunately, most people with schizophrenia are unaware that their symptoms are warning signs of a mental disorder. Their lives may be unraveling, yet they may believe that their experiences are normal. Or they may feel that they’re blessed or cursed with special insights that others can’t see.
For the movie, they modified (for dramatic purposes) the effects of the desease and the cure3. The recovery time period, symptoms, and electroshock therapy sessions are quite inaccurate. "When a true story becomes a major motion picture, screenwriters and directors make adjustments to the storyline to better appeal to an audience. These adjustments often lead to inaccuracies, however."1 From memory, I've also read somewhere2 that writers modified and biased some use of the medication/cure in order to keep people from cutting their treatment off because of the depiction of the desease in the movie.
1. Maria Gaglio - page 6
2. citation needed. (John was able to somehow put his schizophrenia into remission without the use of medication which seems to be something that most experts have not heard of.)
3. In fact, John Nash actually never saw these hallucinations. However, these hallucinations give the audience insight into what it is like to struggle with schizophrenia so they do serve a purpose in the movie. OSU - A Beautiful Mind: Analyzing How Schizophrenia is Portrayed in Movies versus Reality