Trump, like all Americans, has the right under federal law to keep health information from public disclosure. The White House has pledged, though, that physician Rear Admiral Ronny Jackson will issue a public report on the exam, scheduled for Jan. 12 at Walter Reed Medical Center in Bethesda, Maryland.

Trump’s liberal detractors and even some Republicans have recently questioned his fitness for office. A new book on Trump’s White House by author Michael Wolff, Fire and Fury, asserts that almost all of his top staff and advisers believe he is mentally unwell.

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Trump hit back against the claims on Saturday, declaring himself a “very stable genius.” The White House sent out an army of surrogates on Sunday to forcefully denounce the book book and other speculation about Trump’s fitness to serve.

The president himself contrasted his vigor during 2016 with that of his campaign opponent, Democrat Hillary Clinton. pointing to the former Secretary of State’s fainting spell and a persistent cough as evidence she wasn’t physically fit to be elected.

“Hillary Clinton doesn’t have the fortitude, the strength or stamina to lead in our world,” a narrator said in an ad Trump’s campaign ran in October 2016.

Occasional Cigars

Presidential medical reports are typically brief, with an overview of a few basic metrics — cholesterol levels, weight, blood pressure — and may note some idiosyncrasies. In George W. Bush’s first exam as president, his doctor noted he enjoyed the occasional cigar, drank diet soda and ran 12 miles a week. Former President Barack Obama’s exam report chronicled his struggle to quit smoking.

“The president’s health isn’t only of importance to the president but to all of us, so we do expect presidents to reveal information that other people don’t have to, just like their financial information,” said David Orentlicher, co-director of the health law program at University of Nevada, Las Vegas.

Tests Unclear

It’s not known if Trump will receive a mental health screening, though the Obama and Bush medical reports noted that exams showed normal neurological function. Jackson didn’t respond to an interview requested through the White House, and a White House spokesman declined to comment.

Some members of Trump’s own party have raised questions about his psychological fitness for office. Senator Bob Corker has expressed concerns about “his leadership, and just his stability, and the lack of desire to be competent on issues and understand and nothing has changed.”

Stat News, a publication that covers health, reported in May that Trump’s speech had become less articulate in recent years and suggested it could be related to cognitive decline.

‘Astonishingly Excellent’

The White House announced last month Trump’s plan to have a physical after the president slurred words during a speech announcing the U.S. would recognize Jerusalem as the capital of Israel. Press Secretary Sarah Huckabee Sanders said at the time that Trump was simply thirsty and dismissed questions about his health as “ridiculous.”

Trump’s personal doctor, Harold Bornstein, released a letter during the presidential campaign claiming the real estate mogul would be the “healthiest individual ever elected” and that his laboratory tests were “astonishingly excellent.” The letter revealed that Trump took a daily aspirin and a low dose of statin, a drug used to lower cholesterol.

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Presidents don’t always get glowing reviews from their doctors. When President Bill Clinton had a suspicious mole removed in 2001 and saw an increase in his cholesterol level, his doctor said he wasn’t in as good of shape as he would like, calling his results “fairly normal.” Clinton allowed reporters to question his doctor after the exam; Obama and Bush released written summaries.

Jackson was named physician to the president in 2013 and performed Obama’s last physical in 2014. He had previously worked in the White House medical office treating Cabinet members and senior staff since 2006. Sanders said last month that Jackson will issue a public statement on the president’s health after the exam.

Big Macs

Trump has made no attempt to hide his weakness for unhealthy foods, posting a photo of himself aboard his campaign plane with a bucket of fried chicken, bragging about the chocolate cake at his Mar-a-Lago resort and drinking Diet Coke around the West Wing. Trump would sometimes order two McDonald’s Corp. Big Macs, two Filet-O-Fish sandwiches and a chocolate milkshake for dinner, according to a recent book by campaign aides Corey Lewandowski and David Bossie.

Several past presidents have had major health issues while in office that were kept from the public. A Duke University Medical School study found that half of all presidents through 1974 suffered from mental illness, including bipolar disorder, alcohol abuse and depression.

Health Complications

Since the start of the twentieth century, at least 14 of the 20 presidents prior to Trump suffered from a significant health complication while in office, the full extents of which were kept from the public in some cases, according to another analysis, by Aaron Seth Kesselheim, an associate professor at Harvard Medical School.

Among the most prominent was Woodrow Wilson, who suffered a stroke that left him incapacitated, a fact that was kept from his own Cabinet. The doctor for President Dwight Eisenhower, who had a major heart attack and stroke while in office, also withheld the information and misled the public about the extent of his medical problems.

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John F. Kennedy had several health problems, most notably Addison’s disease, an adrenal gland disorder, which was concealed from the public.

The state of President Ronald Reagan’s health was also tightly controlled by the White House, which carefully choreographed media coverage to portray him as robust.

‘No Obligation’

“You probably are not going to get any bad news out of this,” said Art Caplan, a professor of bioethics at New York University. “Just like when you or I get a physical, it is completely up to you what you release about it. There is no obligation to tell anyone anything.”

While presidents aren’t required to have a physical or release the results, it has become standard practice. In a Gallup poll during the 2016 general election, 51% of Americans said the president should release all relevant medical information, an increase from 2004 when 38% held that view.

Caplan said the only way Jackson could legally and ethically release information about Trump’s mental state without the president’s consent is if he determined Trump posed a direct, imminent threat to another person, but that is an extremely difficult standard to meet.

“The standard is so tough to meet in a physical, I can’t imagine that happening,” Caplan said.