I can't stand when people give their characters a million and one psychological disorders as if they're giving out candy. The boy with the retrograde amnesia is fine, but a girl who is Borederline with an eidetic memory, schizophasia, and claustrophobia? It ruins the focus for me personality, and I think it would be easier to focus on one, or maybe two, aspects of the characters problems.
To write a good screenplay you'd need to find what you care about, maybe something you philosophize about on your own from time to time. You could also embed your own personal beliefs into the story. Meanings will begin to arise as you become better acquainted with the characters that are involved in your plot. I know that's not what you want to hear but here are some ideas if you'd like (and it's not too late):
You could do something about relationships (platonic or romantic) because a girl with BPD would have trouble forming them. You could also do something on how memories are precious, or if you don't believe that, you could say that memories aren't necessary to live a good life because Carmichael is doing it. You could also focus on how people with BPD are extreme and both idolize and demonize their loved ones, and maybe create meaning out of that. BPD alone gives you all sorts of crazy to work with.