Perhaps it isn't surprising, given the intense rhetoric of this year's presidential election, that politicians have started throwing around accusations of insanity.   

In early August, California Rep. Karen Bass, a Democrat, launched the hashtag #DiagnoseTrump and started a change.org petition claiming the Republican nominee, Donald Trump, meets the diagnostic criteria for Narcissistic Personality Disorder. Not long after, Trump called Hillary Clinton "unstable," and at a rally in New Hampshire said, "She’s got problems."

The candidates' verbal volley highlights a persistent stigma about mental illness in politics. In the past, an admission of mental health problems was a death knell to political careers. In recent years, a few members of Congress have been open about getting treatment for mental illness, but they remain few and far between. Nevertheless, there's good evidence that even some of the most beloved presidents in American history might have met the modern criteria for mental illness.

Heroic ideal?

The presidency is a high-pressure job, and one that Americans typically view through almost a fairy-tale lens.

"Americans have a version of the presidency in mind, the textbook presidency, that bears very little relationship to the actual job of being president," said Jennifer Mercieca a historian of American political rhetoric at Texas A&M University. Political scientists talk about "heroic expectations" for presidents — that they'll be generally good-hearted, magnanimous and well-meaning. Their health, both mental and physical, is a part of these expectations, Mercieca told Live Science.

"There's definitely a politics of 'fitness' for office," she said. "Using that word as a pun."

In not-so-long-ago elections, mental health issues stalled political ambitions. Perhaps the most famous example was Thomas Eagleton, the 1972 vice presidential pick of Democratic Party presidential nominee George McGovern. Only a few weeks after being chosen, Eagleton withdrew from the ticket after it became public that he'd been treated with electroshock therapy for depression. He went on to a successful career in the Senate, and then worked as an attorney and professor until his death in 2007.

Some politicians have sought to be open about their mental health struggles. Lynn Rivers, a Democrat from Michigan, who served in Congress between 1995 and 2003, was open about having bipolar disorder. Sean Barney, a Democrat who is running to represent Delaware in the House of Representatives, has spoken about coping with post-traumatic stress disorder (PTSD) from his time in the Marines in Iraq, where he was left partially paralyzed after being shot by a sniper. Ruben Gallego, D-Arizona, is another Iraq-veteran-turned-congressman who has talked about seeking help for PTSD.

In the executive branch, however, candidates and presidents have been mum on their own mental health. When John McCain ran in the Republican presidential primary in 2000, he faced a whisper campaign alleging that he was mentally unstable from his time in a Vietnamese prisoner-of-war camp. He released his medical records to the press to counter the rumors.

Presidential pressure

Attitudes toward mental illness have changed since Eagleton lost his shot at the vice presidency. In 1990, Florida gubernatorial candidate Lawton Chiles disclosed that he was taking the antidepressant Prozac. His competition in the Democratic primary, Bill Nelson, said the prescription raised "serious questions" over whether Chiles would be able to perform as governor. But Chiles won the primary, and went on to defeat the Republican nominee and incumbent governor in the general election. When reached in 2015 by Politico about that race, Nelson said, "Knowing what I know now, I never would have said such a thing about [Chiles] or anyone else."

Although the understanding of mental illnesses as biological diseases —and no more the result of a character flaw than cancer or lupus —has expanded, more subtle forms of bias against the mentally ill persist. Several studies have examined implicit biases against people with mental illnesses. Implicit biases are subtle, and people may not consciously realize they have them. Researchers uncover them with rapid word-association tasks. People with an implicit bias against the mentally ill are quicker to associate the word "depressive" with "unpleasant" than "pleasant," for example.

A 2006 study in the Journal of Social and Clinical Psychology, for example, found more negative implicit attitudes toward people with mental illnesses than people with physical illnesses, even among those diagnosed with a mental illness themselves. A 2011 study in the same journal found that people claimed to have similar feelings about depression and physical illnesses, but were more implicitly negative about depression.

Despite all this, there's evidence that some people with mental illness have made it to the White House — and even into the pantheon of most-admired presidents.

A 2006 study in The Journal of Nervous and Mental Disorders took a stab at evaluating the mental health of 37 U.S. presidents, starting with George Washington and ending with Richard Nixon. With caveats about the difficulty of psychologically diagnosing the dead, three psychiatrists analyzed the biographies of these figures and concluded that 18 of them may have had psychiatric disorders at some point. Ten seemed to have been affected while in office. 

Among those 10: John Adams, who may have had bipolar II, a disorder marked by depressions and periods of low-level mania. Franklin Pierce, who saw his 11-year-old son (his last surviving child) crushed in a train accident just after his election, may have had depression and abused alcohol.

Abraham Lincoln regularly ranks in the top three greatest presidents of all time in historian polls, Mercieca said. He also had recurrent depression. Like Pierce, Lincoln lost children. One son, Edward, died in 1850 at age 4. Another, William, died in 1862, while his father was in the White House.

Teddy Roosevelt may have had bipolar I disorder, featuring more extreme mood swings than bipolar II, according to the 2006 study. William Howard Taft could have had a breathing-related sleep disorder. Woodrow Wilson seemed to display signs of depression during his time in office (he also had a stroke during his presidency). Calvin Coolidge had depressive symptoms during his time in office, as did Herbert Hoover, the researchers wrote. Lyndon Johnson frightened his cabinet with dark moods and may have had bipolar disorder. A 1988 article by his special assistant Richard Goodwin argued that Johnson became pathologically paranoid during his time in office. Finally, Nixon showed signs of alcohol abuse, the researchers wrote. 

Some of these presidents were bad leaders (Pierce regularly ranks in the lowest quartile in historian surveys) and others were great (Roosevelt almost always shows up in the top 25 percent in historian polls), rankings recently published by the nonprofit policy group The Brookings Institution show.

Likewise, the eight presidents who had psychological issues that manifested before, but not during, their presidencies, were a mixed bag, the rankings published by Brookings show. Ulysses S. Grant, whose struggles with alcoholism caused scandals during the Civil War, is low-rated by historians. Thomas Jefferson, who met criteria for social phobia early in life, and James Madison, who at times seemed depressed, are both considered above-average presidents and beloved founding fathers.

Original article on Live Science.

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