He's been full-on nuts since at least 2011

A Times article published May 2, 2011, proves it:

He was savagely mocked by President Obama and the comedian Seth Meyers at the White House Correspondents’ Dinner — belittled as a political charlatan with an unchecked ego and a dead fox plastered on his head.

[...]

“Seth Meyers has no talent,” Mr. Trump said in an interview on Sunday. “He fell totally flat. In fact, I thought Seth’s delivery was so bad that he hurt himself.”

[...]

[Trump] said he viewed the rough treatment as a measure of the fear he had struck in the Washington establishment. “It was like a roast of Donald Trump,” he said, clearly reveling in the attention, if not the content.

[...]

None of it, however, answered the central questions posed by his White House flirtation: Is it real or, like his hit series on NBC, a reality show? Even a comment Mr. Trump made to Bloomberg News on Sunday — that he had decided to run “in my mind” — created as much confusion as clarity.

  NYT

We know now, don't we?

During a lengthy conversation in his 61st-floor suite at the Trump International Hotel in Las Vegas [displayed] a detailed understanding of the political landscape and a curious insensitivity toward potential voters.

[...]

At one point, he compared his opposition to the legalization of same-sex marriage to his reluctance to use a new kind of putter.

“It’s like in golf,” he said. “A lot of people — I don’t want this to sound trivial — but a lot of people are switching to these really long putters, very unattractive,” said Mr. Trump, a Republican. “It’s weird. You see these great players with these really long putters, because they can’t sink three-footers anymore. And, I hate it. I am a traditionalist. I have so many fabulous friends who happen to be gay, but I am a traditionalist.”

OK then. Same-sex marriage leads him to think about long putters. I've had that impression of him ever since he came on the political scene. If I'd known anything at all about him before then, I'm sure I would have had it then, too. I think he's afraid of his gay tendencies and overcompensates with womanizing. He certainly doesn't like or respect women.

Mr. Trump spoke knowledgably — and harshly — about Mr. Obama’s health care overhaul and America’s trade policies with China. But at times he betrayed a lack of engagement closer to home, incorrectly stating that only one member of the New York City Council was a Republican. (There are five.)

Mr. Trump, 64, repeatedly found ways to weave the topic of his wealth, and its reach, into the conversation. “Look at that,” he interrupted, pointing to a giant white plane hovering outside the room’s windows. “That’s my plane. How beautiful is that?”

[...]

Should he run [for president], he said, he would relinquish control of his company to three of his children, Donald, Eric and Ivanka, who have worked with him for years. He said that his wife, Melania, 41 — who appeared briefly, bathrobe-clad, to say hello during the interview — had not only encouraged him to run but vowed to campaign with him. “She would be great,” he said.

She walks into the middle of an interview in a bathrobe to say hello? What does that say about her?

...but hey, do what you want...you will anyway.