New York Times columnist David Brooks, the paper's conservative, is once again psychoanalyzing Donald Trump and evaluating his sense of self-worth.

Brooks wrote in the Times on Tuesday that Trump is likely a narcissist struggling to cope with criticism.

"This is a unique moment in American political history in which the mental stability of one of the major party nominees is the dominating subject of conversation," said Brooks, who is not a licensed therapist.

"It's hard to know exactly what is going on in that brain, but science lends a clue," he said. "Psychologists wonder if narcissists are defined by extremely high self-esteem or by extremely low self-esteem that they are trying to mask. The current consensus seems to be that they are marked by unstable self-esteem. Their self-confidence can be both high and fragile, so they perceive ego threat all around."

Brooks' diagnosis comes as Trump is in Cleveland to formally accept his party's nomination for president on Thursday.

In 2012, an actual psychologist, Duke University Professor Allen Frances, called on Brooks to "stop being an amateur psychologist."

"What Brooks doesn't know about psychology is a lot," Frances wrote in the Huffington Post. "Everything he says about it has a shallow ring, is misinformed, and displays the same bias and ulterior motive."