What happened when John Nash stopped taking his medication in a beautiful mind?

When John Nash stopped taking his medication in "A Beautiful Mind," he experienced a resurgence of his schizophrenia symptoms, including hallucinations and delusions. He became increasingly detached from reality, believing in elaborate conspiracies and imaginary friendships. This deterioration strained his relationships and jeopardized his career, ultimately leading him to confront the challenges of managing his illness without medication. The film highlights Nash's struggle between his genius and the impact of his mental health.