The Wall is the answer.

The Wall. Specifically The Wall from 1979. It’s the one that follows a rock star named Pink losing his mind while World War II trauma, authoritarianism, and his own isolation push him over the edge. War is baked into his origin story (his father died in combat), and mental illness is the whole arc — paranoia, hallucinations, the works.

The Final Cut (1983) is the other one. It’s more explicitly about war and PTSD,