The chorus of concerns about U.S. President Donald Trump's mental health capacity is now louder than ever. Critics believe his behaviour has demonstrated that he may be unfit to hold the office of president or worse, that he's a danger to humanity.

They point to examples like this: Trump says he won't visit London to open the new U.S. embassy because he doesn't like its location, not because relations between Britain and the U.S. are at a historic low.

He's faced accusations of swearing in a racist way about people from places such as Haiti and Africa. Accusations he denies.

Trump says he's probably got a very good relationship with the leader of North Korea after tweeting thinly veiled nuclear threats.

....to President of the United States (on my first try). I think that would qualify as not smart, but genius....and a very stable genius at that! —@realDonaldTrump

Earlier, in a bid to counter the claims about his mental health he wrote on Twitter that "would qualify as not smart, but genius … and a very stable genius at that!"

And of course, there are the revelations from Michael Wolf's now infamous book Fire and Fury. It's about Trump's first year in the White House. Wolf told The Current's Anna Maria Tremonti that everyone in the White House is aware and disconcerted by Trump's constant repetitions of speech. "Within the White House, there's kind of a measure of this, saying, it used to be that he'd repeated the same three stories — the same words, same facial expressions, same tone, you got those same stories within 30 minutes. As months went on, that time began to shrink where you'd get the same stories within 10 minutes."

All this comes as the National Coalition of Concerned Mental Health Experts, led by Dr. Bandy Lee — a forensic psychiatrist with an expertise in violence at the Yale School of Medicine — issued a statement calling for an emergency evaluation into Trump's behaviour and mental health.

Last month and again this week, psychiatrists led by Lee met with members of Congress to express their concerns about Trump's fitness for office.

Stress might be contributing to Trump's erratic behaviour

"A number of us have been concerned for quite some time, but now it has become more acute as we had predicted. Mr. Trump has grown worse over time and has become increasingly difficult to contain," says Lee. "Now let me qualify that we are not diagnosing Mr. Trump. Mr Trump's personal mental health condition does not concern us. What concerns us is the effects that his mental instability would have on public health."

Dr. Bandy Lee from Yale School of Medicine is leading a coalition of mental health experts calling for an emergency evalution of U.S. President Donald Trump's mental fitness to serve. (Yale University)

Lee says she became very concerned when special counsel Robert Mueller's indictments were being put forth, Trump was beginning to show signs of unraveling, what she calls "decompensating." She says when someone starts to lose touch with reality, becomes more impulsive and volatile, that person's coping skills become maladaptive. "In the case of Mr. Trump, he often resorts to violence or attack mode when he becomes stressed. And there was a period when he was retweeting violent imagery and videos. He was starting to re-espouse conspiracy theories he had abandoned in the past, and he was denying his own voice on Access Hollywood tapes that he had admitted to before."

Concerning signs

It was Trump's tweet on Jan. 2 about the size of his nuclear button that led Lee and the National Coalition of Concerned Mental Health Experts to issue a statement calling for an evaluation into Trump's psychological health, which she says will be given to both the U.S. Cabinet and Congress members.

North Korean Leader Kim Jong Un just stated that the “Nuclear Button is on his desk at all times.” Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works! —@realDonaldTrump

Lee says this tweet in context of his verbal aggressiveness, his history of boasting about sexual assault, inciting violence at his rallies, endorsing violence in key speeches, he has shown an attraction to violence and powerful weapons, and his increased provocation of not only hostile nations but also allies, all point toward danger for the world's most powerful nuclear nation. "The last time we checked, there are no checks in between his order and launching them within five minutes."

Many have argued this is just how Trump operates, but Lee and other members of her coalition say this is where the input of mental health professionals might be helpful, "because most people will view his method and style as a variation of the normal. But despite there being a wide range within human normalcy, when it gets into the domain of the pathological, where choices will be made not out of reason and strategy, if you will, but out of pathology, out of symptoms — emotional compulsion say or not being able to help oneself, then it becomes very concerning."

Another potential symptom that Lee saw, which concerned her, was Trump's Dec. 6, 2017, speech when he recognized Jerusalem as the capital of Israel and slurred as he spoke. The White House has said it was just a case of dry mouth, but again, Lee says that it could be a sign of something more that could only be narrowed down with a full physical and mental evaluation. "A full evaluation is necessary, but I would be worried about anything from medication induced to some kind of neurological event, including a temporary stroke."

It's not just this example of slurred speech that worries many psychiatrists, Lee included. Trump's style of speech in his Dec. 28, 2017, interview with the New York Times is what she says is a "cognitive sign."

"It was again showing signs of great concern, including inability to complete sentences, a lack of ability to keep with a thought, showing less complex words than he had used in the past, and jumping from one topic to another, repetition of words, repetition of stories, those are all what we call 'cognitive signs.' Those can happen because of neurological process, psychiatric process, medication induced or a physical process. We simply do not know," says Lee. But she says for a person in such a position of power that until they determine what's going on, 'It is a national and international security risk."

Ethics of commenting on Trump's mental health

"Mental illness in itself is a private affair. It does not concern his ability to function. Fitness for duty is a whole separate issue," says Lee. "And also what we're speaking about, which is his dangerousness, is again yet a separate issue, and that not all mentally ill persons are dangerous. In fact, they are no more dangerous than the general population. And one does not have to have mental illness to be dangerous."

There is a rule known as the "Goldwater Rule," which says that psychiatrists should not diagnose public figures unless they have directly evaluated them. Dr. Jeffrey Leiberman, the chair of Columbia University's Department of Psychiatry, says what Lee is doing by by commenting on Trump's mental health as a psychiatric expert is unethical.

"What makes it more problematic, apart from just the inappropriateness of it, and it's acting in a way that doesn't pursue the constitutionally defined remedies for presidential misbehaviour or incompetence," says Leiberman. And that it's "falling into a trap of being used for partisan political reasons or other nefarious purposes."

Forensic psychiatrist Dr. Bandy Lee from Yale School of Medicine edited the book The Dangerous Case of Donald Trump: 27 Psychiatrists and Mental Health Experts Assess a President. (MacMillan Publishers)

Lee says she is simply acting as an expert consultant. "I've done this for a half dozen state governments, for prison reform and violence prevention, I have done it with international governments in Ireland and France, I know what being an expert consultant means. I do not confuse political use of expert testimony with what I am providing as a medical professional and as an expert witness. Medicine does not have to do with ideology. It is not political. It is based on evidence, facts, observable data, and there is often a consensus throughout the field."

She says another reason she feels this pushback from Lieberman is questionable is "because Dr. Lieberman does break the Goldwater rule, proposes a diagnosis for the president, even the location of the defects in a popular article."

"I know that there are risks involved in sounding this alarm, but someone has to break the silence," says Lee. "And many are waiting to speak, but they do not feel safe in doing so yet."