Trump Shows ‘Unmistakable’ Signs of Advanced Dementia, Experts Say. Why Is He Still President?

In 2017, early in Trump’s first term, a coalition of mental health professionals warned that Trump’s mental health posed a “clear and present danger,” threatening both the nation and individual well-being. They set out their case in “The Dangerous Case of Donald Trump,” a book edited by forensic psychiatrist Dr. Bandy X. Lee. Many fears set out in the book – as well as in subsequent expanded editions – have already come true.

Among other things, contributors argued that Trump’s malignant narcissism, cruelty and pathology would put the country at grave risk of involvement in war. Indeed, Trump’s recklessness, including killing people on fishing boats, an illegal invasion of Venezuela, threats to Mexico and numerous other countries, and now a fixation with Greenland, puts our country – and the world – at grave risk. He pushes responsibility for this escalated tension onto others – in the case of Greenland, onto Norway’s Prime Minister, for not giving him the Nobel Peace Prize (the prize is awarded by a committee independent of the Norwegian government.) Or, as Substack columnist Jeff Tiedrich summarizes: “Spite-fueled toddler claims he gets to have Greenland because he didn’t get a Nobel Peace Prize.”

Contributors to “The Dangerous Case of Donald Trump” also warned that Trump would seek to undermine democracy at home, and we’ve seen that bear out in his attempted January 6 coup and then throughout his second presidency, from the rampages of DOGE to the lawlessness of ICE. 

But the authors did not just warn that Trump was dangerously callous, mentally disturbed and showing clear psychopathic tendencies. In later interviews, petitions and editorials, Bandy Lee and others pointed out that he was showing hallmark signs of cognitive decline, including in a statement on the World Mental Health Coalition’s website. Their concerns included not only Trump’s incoherence, impaired memory, and “confabulation, where memory gaps are filled with false or fabricated details,” but also an “amplification” of his paranoid, narcissistic, and antisocial personality traits, which they described as “criminal and dangerous.” The experts also noted Trump’s aggression, disinhibition in behavior and vulgar, hateful language. 

Former Johns Hopkins professor Dr. John Gartner has raised similar concerns, both in media appearances and a 2024 petition saying that. “Donald Trump is showing unmistakable signs strongly suggesting dementia, based on his public behavior and informant reports that show progressive deterioration in memory, thinking, ability to use language, behavior, and both gross and fine motor skills.” 

​​In an April 2025 conversation with MindSite News, Gartner explained his conviction that “there was absolutely no doubt” that Trump has dementia. “We’ve collected dozens and dozens of Trump’s phonemic paraphrasias, in which you use sounds in place of an actual word (a hallmark of brain damage and dementia),” said Gartner in one of the many examples he gave. “Trump will say something like ‘mishiz’ for missiles, or ‘Chrishus’ for Christmas, because he can’t complete the word. He is losing his capacity for coherent speech…Then there is the physical deterioration. He used to be quite graceful, and now he uses a wide-based gait typical of frontotemporal dementia.” Trump was also confusing generations and people, a sign of severe dementia, Gartner told us, saying more than 8 times that he has run for president against Obama. In a recent appearance on The Daily Beast Podcast, Gartner notes that “the paranoia is becoming more grotesque, more primitive.”

You don’t need to have taken care of a loved one with Alzheimer’s disease to imagine how terrifying it is to have someone with dementia in control of nuclear weapons – someone perhaps lacking the wherewithal to resist coercion from those around him, or the impulse control to behave responsibly. Yet this is exactly where we find ourselves. In September, according to The Guardian, Trump gathered military commanders, praising a potentially illegal bombing of Iran before describing how President Obama went down the stairs: “Da da da da da da, bop, bop, bop.” 

The 25th Amendment includes a provision to remove the President when they are “unable to discharge the powers and duties of his office.” The governor of Illinois, J.B.Pritzker, specifically mentioned dementia when calling for the use the 25th Amendment in September, a comment that came after the president said cities like Chicago should be used “as training grounds for the military.” 

Most Republicans seem determined to keep their head in the sand, but Trump’s increasingly erratic activity this week has prompted more calls to have him removed, including from Senator Ed Markey, as well as Representatives Eric Swalwell and Yassamine Ansari, the latter of whom wrote on X that “The president of the United States is extremely mentally ill and it’s putting all of our lives at risk. The 25th Amendment exists for a reason – we need to invoke it immediately.”