A simple way to identify narcissistic people

It's a hopelessly self-referential process. You directly ask someone if they self-identify as a narcissist, and use their reply to avoid asking a hundred questions that would only have produced the same outcome, for the reason that the superficial question, and the elaborate approach, both rely on self-reporting, the bane of psychology.

If someone should successfully explain why some people are narcissists, and create a test that doesn't rely on asking stupid, predictable questions but uses an objective diagnostic test (imagine a microscope instead of a microphone), then such discussions would move away from empty philosophy, toward science.