And so it is, or ought to be, with Donald Trump. You don’t need to be a weatherman to know which way the wind blows, and you don’t need to be a mental-health professional to see that something’s very seriously off with Trump—particularly after nearly three years of watching his erratic and abnormal behavior in the White House. Questions about Trump’s psychological stability have mounted throughout his presidency. But those questions have been coming even more frequently amid a recent escalation in Trump’s bizarre behavior, as the pressures of his upcoming reelection campaign, a possibly deteriorating economy, and now a full-blown impeachment inquiry have mounted. And the questioners have included those who have worked most closely with him.

No president in recent memory—and likely no president ever—has prompted more discussion about his mental stability and connection with reality. Trump’s former chief of staff John Kelly is said to have described him as “unhinged,” and “off the rails,” and to have called the White House “Crazytown” because of Trump’s unbalanced state. Trump’s former deputy attorney general, Rod Rosenstein, once reportedly discussed recruiting Cabinet members to invoke the Twenty-Fifth Amendment, the Constitution’s provision addressing presidential disability, including mental disability.

Rosenstein denies that claim, but it is not the only such account. A senior administration official, writing anonymously in The New York Times last September, described how, “given the instability many witnessed, there were early whispers within the cabinet of invoking the 25th Amendment”—but “no one wanted to precipitate a constitutional crisis.” And NBC News last week quoted someone familiar with current discussions in the White House warning that there is “increasing wariness that, as this impeachment inquiry drags out, the likelihood increases that the president could respond erratically and become ‘unmanageable.’” In September, a former White House official offered a similar assessment to a Business Insider reporter: “No one knows what to expect from him anymore,” because “his mood changes from one minute to the next based on some headline or tweet, and the next thing you know his entire schedule gets tossed out the window. He’s losing his shit.”

Even a major investment bank has gotten into the mix, albeit in a roundabout way: JPMorgan Chase has created a “Volfefe Index”—named after Trump’s bizarre May 2017 “covfefe” tweet—designed to quantify the effect that Trump’s impulsive tweets have on interest-rate volatility. The bank’s press release understatedly observed that its “volatility fair value model” shows that “the president’s remarks on this social media platform [have] played a statistically significant role in elevating implied volatility.”