A former FBI profiler says Trump shows the 'biggest hallmark of the narcissist'

By the New York Times' count, Republican presidential nominee Donald Trump has lobbed personal attacks on Twitter at 282 people, places, and things since declaring his candidacy last June.

For Joe Navarro, former FBI profiler of 25 years and author of "What Every Body Is Saying," those attacks aren't 282 separate anomalies - they're each a telling glimpse into the candidate's patterned display of narcissism and lack of empathy.

"Insults speak to overvaluation of self and devaluation of others," says Navarro, who helped found the FBI's Behavioral Analysis Unit and has profiled thousands of people over his career, from white-collar thieves to murderers. "This is the biggest hallmark of the narcissist."

Like any observation-based judgment, assessing character flaws can be a slippery slope. Sometimes they are harmless, and a person's perceived coldness may just be a sign they're standoffish. But other times they may reveal a person's potential for destruction.

In Trump's case, Navarro views the repeated denial of any allegations against him and patterned verbal abuse - calling various members of the media, business, and politics "losers," "dopey," "crooked," and much more - as clues that Trump may have fundamental flaws in his character.

"When it's dangerous is when it's a consistent way of dealing with life, like a bully, and it's sort of your default mechanism," he says. "This doesn't produce good relationships. What it does ensure is that you're always on top, and people are below you."

According to a Bloomberg poll conducted in August, the most egregious behavior came last November during one of Trump's rallies in South Carolina when he apparently mocked journalist Serge Kovaleski, who has a mobility-limiting condition known as arthrogryposis.

"That shows me that he has no empathy for someone who has a mental or cognitive malady," Navarro says.

Trump later denied the claims, saying he didn't know what Kovaleski looked like when he gave the speech. But Kovaleski said shortly after that he's known Trump for some time. "Donald and I were on a first-name basis for years," he told the Times.

Navarro concedes there are limitations to assessing the severity of Trump's lack of empathy, however. Proper evaluations take place in a controlled setting with the person in question or someone who knows the person well. Twitter insults and videos in the news aren't substantive evidence that someone is dangerous.

But that doesn't mean glimpses into someone's personality aren't important.

If Trump had made just one contentious remark over his 18-month campaign, he might have given off a different general impression. But the last year and a half has been littered with incendiary claims, many of which Navarro says are cause for concern that Trump lacks an ability to show true compassion.

"Does that portend other things?" Navarro says. "Yeah, because what's at the extreme end of lack of empathy? Psychopathy. That's why I argue you can't dismiss character flaws."