Is Donald Trump psychologically unstable and unfit for office? Does the president of the United States have a dangerous mental illness of some shape or form?

Ask his fellow Republicans.

During the GOP primaries, Marco Rubio suggested he was a “lunatic,” Rand Paul dubbed him a “delusional narcissist,” and Ted Cruz denounced him as “utterly amoral” and “a narcissist at a level I don’t think this country’s ever seen.” Mitt Romney opined, “His is not the temperament of a stable, thoughtful leader,” and Jeb Bush declared, “He needs therapy.”

In recent months, Sen. Susan Collins, R-Maine, has admitted she is “worried” about the president’s mental health, and Sen. Bob Corker, R-Tenn., has warned that Trump “has not yet been able to demonstrate the stability nor some of the competence” necessary for a successful presidency.

Ask the ghostwriter of his best-selling book, “The Art of the Deal.”

Tony Schwartz has called Trump a “sociopath” and has said “there is an excellent possibility” that the Trump presidency “will lead to the end of civilization.”

Ask the voters.

One in three Americans say they believe Trump’s mental health is “poor” while two out of three regularly question his temperament. Four in 10 voters in the swing state of Michigan — which helped deliver the White House to Trump — say they think the president is “mentally unstable” while a majority of them are worried that he has access to the nuclear codes.

Ask the experts.

In a new book published this week, “The Dangerous Case of Donald Trump,” a group of 27 psychiatrists and mental health experts warn that “anyone as mentally unstable as this man should not be entrusted with the life-and-death-powers of the presidency.” Seemingly in defiance of the American Psychiatric Association’s “Goldwater rule,” which states “it is unethical for a psychiatrist to offer a professional opinion [on a public figure] unless he or she has conducted an examination and has been granted proper authorization for such a statement,” the various and very eminent contributors paint a picture of a president who has “proven himself unfit for duty.”

Stanford University psychologist Philip Zimbardo — of the famous Stanford prison study — suggests the “unbalanced” Trump is a “specific personality type: an unbridled, or extreme, present hedonist” and “narcissist.” Psychiatrist Lance Dodes, a former Harvard Medical School professor, says Trump’s “sociopathic characteristics are undeniable” and his speech and behavior show signs of “significant mental derangement.” Clinical psychologist John Gartner, a 28-year veteran of Johns Hopkins University Medical School, argues that Trump is a “malignant narcissist” and “evinces the most destructive and dangerous collection of psychiatric symptoms possible for a leader.” For Gartner, the “catastrophe” of a Trump presidency “might have been avoided if we in the mental health community had told the public the truth, instead of allowing ourselves to be gagged by the Goldwater rule.”

“The Dangerous Case Of Donald Trump” was conceived of and edited by Professor Bandy Lee, a forensic psychiatrist on the faculty of Yale School of Medicine, who writes of her profession’s moral and civic “duty to warn” the American public about the threat posed by their volatile, erratic, and thin-skinned president.

On the latest edition of my Al Jazeera English show, “UpFront,” I spoke to Lee about Trump’s mental state, the purpose of the book and the arguments put forth by her critics. The interview has been lightly edited and condensed.

Mehdi Hasan: Why did you write this book and what is your main message?

Bandy Lee: We are a group of mental health experts who have come to a consensus conclusion about an issue that is of vital interest to the public and that the public has a right to know: basically, that Mr. Trump in the office of the presidency is a danger to the public and the international community. We are not purporting to make a diagnosis. Assessing dangerousness is different from diagnosing someone for the purpose of treatment. I’m speaking on my own behalf and not representing the views of Yale University, Yale School of Medicine, or Yale Department of Psychiatry.

MH: According to a study by experts at the Duke University Medical Center, around one in four presidents have had some sort of mental illness while in office. So why is Trump so special?

BL: Mental illness itself does not involve an incapacity to carry out a duty. It’s really the specific symptoms, the severity of the symptoms, and the particular combination of … impulsivity, recklessness, an inability to accept facts, rage reactions, an attraction to violence, a proneness to incite violence — all these things are signs of danger.

MH: Allen Frances, the famous psychiatry professor who wrote a manual on diagnosing mental disorders, has denounced your book, saying: “Bad behavior is rarely a sign of mental illness. … Psychiatric name calling is a misguided way of countering Trump’s attack on democracy.” What’s your response to him?

BL: Actually, I don’t think we’re that much in disagreement. We are declaring dangerousness, which is different from making a diagnosis. I am of the camp that believes it is necessary to do a full interview and to [have] all the information, including any medical conditions, any other disorders, that could explain behavior before making a diagnosis. So, again, we are not purporting to make a diagnosis. The conjecture is that he shows signs of severe mental impairment. We are concerned enough that we are calling for an urgent assessment.

MH: A lot of presidents were narcissists, egomaniacs, incited violence, suffered from conditions such as depression. People didn’t question their fitness for office, did they?

BL: That is right. Very few conditions are dangerous. Very few conditions would make one unfit for duty. In this particular situation, we are declaring a danger to the public and to international security. I can tell you as an expert on violence that he has shown many signs of dangerousness. The most obvious ones might be verbal aggressiveness, history of sexual assault, incitement of violence at his rallies, attraction to violence and powerful weapons, [provoking] hostile nations, and, more recently, an endorsement of violence, during [the protests in] Charlottesville, and sparring with another nuclear power that has an unstable leader. All these things are signs of dangerousness.

MH: There’s been talk of setting up a commission of mental health experts to evaluate every future president and perhaps advise Congress on a president’s fitness for office. Should Donald Trump be removed from office based on his mental state? Should the 25th Amendment, which discusses how to remove a president if he is “unable to discharge the powers and duties of his office,” be invoked?

BL: Well, we’re merely recommending that procedures be put in place to evaluate every presidential candidate and every president, in the same manner that every military officer and every civilian service person is put through. That the commander-in-chief is not put to the same test is a glaring omission. Currently we are advocating the setting up of an expert panel to advise a commission and we’re recommending that the panel consist of psychiatrists, clinical psychologists and neurologists.

MH: But you’re of the view that there is a case for removing Trump from office based on his mental state?

BL: There are many signs pointing in that direction and so we’re calling for an urgent evaluation.

MH: How worried should we be that Trump has access to the nuclear codes?

BL: Well, that is our critical concern: that his condition is actually probably far worse than people are detecting now; that [his] mental impairment goes deeper and is far more pervasive than people can understand when they are untrained in psychological matters. And that the worst is yet to come.