What stressor precipitated John Nash's first episode of schizophrenia in "A Beautiful Mind"?

John Nash had long been considered to be eccentric, but it was not until he was thirty years old that he suffered his "first shattering episode of paranoid schizophrenia" (Prologue).  In the summer of 1957, Nash began work on a project to "revise quantum theory".  Decades later, Nash would blame this attempt to "resolve the contradictions in quantum theory", as the stressor that precipitated his mental illness.  He called his efforts to explore the depth of the science "possibly overreaching and psychologically destabilizing" (Chapter 30).