If his public remarks are any indication, few topics are of greater interest to Donald Trump than cognitive tests. The president has long struggled to understand the point of these tests, but that hasn’t stopped him from his obsessive boasts about being able to pass exams used to identify dementia, mental deterioration and neurodegenerative diseases.

On Friday, for example, Trump spoke to a supportive crowd in Florida, where he went on an extended riff, claiming that he’s the only president to have taken a cognitive test, pretending it’s impressive that he’s taken three and insisting that Barack Obama would fail such a test......

I am going to resist the temptation to comment on that quote and will instead note that around the same time, the president suggested some of his own supporters on hand for the event would struggle to answer the questions on the exams he’s taken repeatedly for reasons the White House hasn’t explained.

Trump suggests his own supporters couldn’t pass a cognitive test.

I took three of them. I'm the only president to take a cognitive test. I don’t think Obama could pass it. The first question is a lion, a giraffe, a bear, and a shark. A lot of you wouldn’t have been able to answer those questions.

— Acyn (@acyn.bsky.social) 2026-05-01T20:50:37.879Z

If it seemed that Trump was feeling a bit defensive on the issue, it’s easy to understand why. It was just a few weeks ago when The New York Times published a striking report with an unsubtle headline: “Trump’s Erratic Behavior and Extreme Comments Revive Mental Health Debate.” The same article highlighted a lawyer who used to work with Trump who described the president as “a man who is clearly insane.”

It also noted a recent comment from Stephanie Grisham, a former White House press secretary who worked for Trump in his first term. Grisham wrote online a week earlier that her former boss is “clearly not well.”....

But just as important is the degree to which Trump’s fixation on the subject doesn’t seem to be persuading anyone. As recently as November 2024, when he won a second term, a Pew Research Center poll found that 55% of Americans considered the Republican to be “mentally sharp.” That number has now dropped to 44%, with slides among Democrats, independents and even GOP voters.

If the president wants to reassure the public he’s mentally fit to serve, he’ll have to try something other than obsessing over his alleged successes on dementia tests.