Pathological lying, however, creates a dangerous reality that is important to recognize. Going beyond isolated falsehoods within the context of a shared reality, lying that comes from pathology creates an “alternative reality,” which comprises those “alternative facts.” And the more the creator believes his own lies, because of delusions, paranoia, or some other overwhelming emotional need, the more convincing they will be to vulnerable segments of the population. Thus we find ourselves in worlds-apart perspectives that elude reality-based problem solving: It is the sound of one hand clapping. Understanding why Trump lies is even more important, because once we fall into a malignant normality that defies healthy dialogue, we are deprived of the meeting ground of shared consensual reality.

The fact that President Trump lies multiple times a day has become inescapably obvious to all but his most blinkered supporters. In that group of hard loyalists, his inveterate lying doesn’t merit direct refutation, just proper appreciation. Trump adviser Kellyanne Conway introduced us to “alternative facts,” which imply that the president does not see the utility of participating in our truth when his “gut” is much more reliably Donald-friendly. Rather, he operates alongside or above our truth through his own elusive discernment, always confidently doubling down. We, the benighted, are mired in a universe defined by science, history, and direct observation that clearly can no longer be trusted, since it is offered via “the enemy of the people” or “fake media” who, when challenging the president, deserve derision and dismissal.


Absent a thorough neuropsychiatric evaluation of the president, we may not know for years whether Trump asserts untruths out of a profound psychopathic personality structure or the intractable but historically successful habit of the chronic used car salesman or carnival barker. What we do know is that, if he falls in the former category, the public should be aware of the dangerous implications of his staying in power another two years. Mental health professionals analyze and interpret human behavior patterns in many ways outside of the more rigorous technical task of diagnosing, which usually requires a personal examination. In Trump’s situation, we have a lot more information about his dangerousness than almost any of the patients we have seen, given the voluminous high-quality data on him, including numerous personal accounts as well as observations in real time. For example, multiple sources generally agree that the president has lied an astounding 7,645 times during 710 days in office.

We know, at least, that his lying is of a pathological level. Pathological lying may arise in individuals who feel intolerably inadequate, and the ability to gain an “upper hand” by cheating others fulfills the need for power and denial of the painful feelings of smallness and weakness. Nothing, not relationships nor duty, overrides the inner need to posture successfully, to show the world one is not what one in fact fears himself to be. If targets for exploitation are available — the powerless refugees, those with disabilities, or disenfranchised minorities — such an individual relishes his ability to debase and humiliate those external embodiments of his feared inner self. We indirectly glimpse his insecurity in his thin-skinned defensive protests about his “big brain,” “best memory,” and assertion “I’m a technology expert,” etc. These are tips of a much larger iceberg that likely reaches a depth unfathomable for most normal people.


The self-delusion of strength is propped up by lying, both in the repeated, bald assertions of untruth, sometimes called The Big Lie, but also in the delegitimizing of well-established though imperfect purveyors of truth, such as “the failing New York Times.” The repeated, tireless, and unhesitating practice of lying, each lie compounding and somehow eclipsing the one before, buttresses the liar’s inflation, his conviction that he defines reality, not just for him but for his enablers and acolytes, not to mention the “losers” gasping in futile outrage. This level of lying catches us off guard. Our clumsy responses paradoxically normalize his behavior, as though the difference was a mere matter of opinion.


It is certainly true that Trump isn’t a man of rigor. He doesn’t make an effort to learn what is true. He doesn’t read briefing memos , he doesn’t tolerate advisers with alternate perspectives, he is happy to have his reality spoon-fed him by Fox News. He is an incredibly lazy man who reportedly does not believe in exercise, takes golf carts around summit meeting locales, gorges on steak and ketchup while weighing in at an alleged (and widely doubted) “ 239 pounds .” As undisciplined and self-indulgent as he is, his ride down a gold escalator into the presidency was exquisitely symbolic. He does not trouble himself over uncomfortable realities — what is ultimately true though complex, difficult, and nuanced. And it is equally true that his fear of his own inadequacies would have prevented him from serious study of any subject, which would require acknowledging that there are things he does not know and for which he must rely on others, not on his “ gut.

As psychiatrists who have called attention to the president’s mental impairments, we have been asked many times, “Does Donald Trump know he is lying? Is he just a great actor playing a clever role at a fortuitous time, or does he believe his lies and so can deliver them smoothly, without an internal hitch?” We have a good guess as to where his delusions end and his conscious fights for survival of the self begin, but only a full neuropsychiatric evaluation by appropriately trained professionals, hopefully with the help of standardized scales, will help us to qualify and quantify these manifestations.

What we can say beyond doubt, however, is that he is unimpeded by empathy, duty, or shame and is wedded, in dangerous ways, only to what nurtures his exaggerated self-image. If he merely trafficked in condos and apartment buildings, he would threaten only credulous buyers. As things stand, his disregard for truth imperils our country and the world.


Dr. Leonard L. Glass is a psychiatrist at Harvard Medical School. Dr. Bandy X. Lee is a forensic psychiatrist at Yale School of Medicine. They are co-authors of “The Dangerous Case of Donald Trump: 27 Psychiatrists and Mental Health Experts Assess a President.”