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Reports speculating that President Donald Trump has narcissistic personality disorder are misguided and incorrect, a leading psychiatrist argues this week.

He should know. Dr. Allen Frances, professor emeritus of psychiatry at Duke University Medical College, wrote the book on it.

President Donald Trump holds an African American History Month listening session at the White House on Feb. 1. Pool / Getty Images

“Most amateur diagnosticians have mislabeled President Trump with the diagnosis of narcissistic personality disorder. I wrote the criteria that define this disorder, and Mr. Trump doesn’t meet them,” Frances wrote in a letter to the New York Times.

Frances chaired the team that defined psychiatric disorders for the mental health profession — the Diagnostic and Statistical Manual of Mental Disorders IV (called DSM 4). The DSM V or 5 is the most recent edition.

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“He may be a world-class narcissist, but this doesn’t make him mentally ill, because he does not suffer from the distress and impairment required to diagnose mental disorder,” Frances wrote.

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A personality disorder must lead to “clinically significant distress or impairment in social, occupational, or other important areas of functioning,” the DSM IV says.

“Mr. Trump causes severe distress rather than experiencing it and has been richly rewarded, rather than punished, for his grandiosity, self-absorption and lack of empathy,” Frances wrote.

“It is a stigmatizing insult to the mentally ill (who are mostly well behaved and well meaning) to be lumped with Mr. Trump (who is neither).”

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Psychiatrists tend to follow what’s called the Goldwater Rule, a 1973 addition to the American Psychiatric Association’s code of ethics that forbids the diagnosis of public figures they have not personally examined.

It’s named after former presidential candidate Barry Goldwater, who was skewered by some psychiatrists during the 1964 presidential campaign.

“It is a stigmatizing insult to the mentally ill (who are mostly well behaved and well meaning) to be lumped with Mr. Trump (who is neither).”

But some mental health experts, including psychiatrists, have said Trump is so dangerous that they must speak out.

On Feb. 13, the New York Times published a letter signed by 33 psychiatrists, psychologists and social workers.

“We believe that the grave emotional instability indicated by Mr. Trump’s speech and actions makes him incapable of serving safely as president,” they wrote.

Frances disagrees.

“Psychiatric name-calling is a misguided way of countering Mr. Trump’s attack on democracy. He can, and should, be appropriately denounced for his ignorance, incompetence, impulsivity and pursuit of dictatorial powers,” he wrote.

“His psychological motivations are too obvious to be interesting, and analyzing them will not halt his headlong power grab. The antidote to a dystopic Trumpean dark age is political, not psychological.”