As of that time, there were no widely known or documented allegations or claims suggesting that Karl Böhm, the Austrian conductor, had narcissistic personality disorder or any other mental health condition.
Diagnosing a personality disorder, including narcissistic personality disorder, requires a comprehensive assessment by a qualified mental health professional who has access to the person's history, behaviors, and interactions. It is not appropriate to make assumptions or speculations about an individual's mental health without proper evaluation.
Keep in mind that discussing or speculating on the mental health of individuals, especially public figures or historical figures, can be ethically sensitive, and it's essential to focus on their achievements and contributions rather than making conjectures about their personal lives.