Is it ethical to diagnose Donald Trump with a personality disorder if you've never treated him?

Back in 2017, a book was published called The Dangerous Case of Donald Trump: 37 Psychiatrists and Mental Health Experts Assess a President.

US President Donald Trump.

Each author separately postulated that Mr Trump had a narcissistic personality disorder and as such was unfit to hold office.

The features of the disorder listed in DSM-V are as follows:

  • A