Bandy X. Lee is assistant clinical professor in law and psychiatry at Yale School of Medicine and a project leader for the World Health Organization. Tony Schwartz is the chief executive of The Energy Project and the co-author of The Art of the Deal.

Why is President Donald Trump behaving in ways that seem ever more irrational, impulsive, self-destructive, dangerous and cruel? Many Americans have been shocked by Trump’s behavior, most recently by his taking the side of a known enemy in Vladimir Putin and Russia over his own intelligence community.

It isn’t possible to reliably diagnose any individual from a distance, but it is reasonable to flag clear, observable signs of impairment and to make inferences based on repetitive patterns of behavior. There is a significant difference between diagnosing a specific disorder and analyzing the meaning of the qualities Trump exhibits, such as paranoia, grandiosity, lack of empathy and pathological deceit. Trump’s behavior, we believe, is the predictable outgrowth of this psychological disposition, exacerbated by the stress of the intensifying criminal investigations he faces.


Our assessment is based on descriptions from those who have worked with him, his own voluminous responses to real situations in real time, and above all by our unique vantage points. One of us is a forensic psychiatrist who has treated more than 1,000 individuals with characteristics similar to Trump’s. The other spent 18 months shadowing, observing and interviewing Trump in order to co-write The Art of the Deal.

Trump’s increasing grandiosity is evident in the superlatives he uses to refer to himself—“stable genius” among them—and in the way he has consolidated his power by getting rid of aides and Cabinet members who have challenged his authority. Because no person or circumstance can possibly satisfy his needs, nearly everyone in his life eventually becomes expendable, and he becomes more and more isolated.

Trump’s growing paranoia is reflected in the vitriolic comments he has made about a range of perceived enemies, including Democrats and Republicans, allies in the G-7, the intelligence community, the news media and immigrants. His hunger for absolute power is evident in his bizarrely admiring words about despots, including North Korea’s Kim Jong Un, Russia’s Vladimir Putin, China’s Xi Jinping, Turkey’s Recep Tayyip Erdoğan and the Philippines’ Rodrigo Duterte. His frequent lies reveal his need to redefine reality when the truth doesn’t serve his needs.

Given Trump’s volatility, incuriosity and severely limited attention span, his decisions are not significantly influenced by reflection or analytical reasoning. Because he cannot tolerate even the mildest criticism, he is largely immune to learning and growth. Instead, unable to regulate his emotions, he reacts angrily, and often with threats of revenge, to any challenge to his authority. Even success provides him with only momentary satisfaction.

Trump’s psychological disposition has profound implications for our personal, national and international security. Unfortunately, Americans remain deeply reluctant to talk openly about mental health or to recognize how profoundly it can influence behavior. Because the president’s level of mental impairment is so unusual to observe, it is difficult for most of us to understand what catastrophic desperation such people can feel to fill their own inner sense of emptiness.

Trump described to Tony a cold father with whom his relationship was “almost businesslike” and a mother who was mostly uninvolved in his life. Through Bandy’s work interviewing men who were deprived in childhood of the love and support necessary to develop a core self, she concluded that the stable internal center that holds their beliefs, principles, attachments, loyalties—and even their capacity for humanity—never gets well established.

Instead, most such men become almost completely dependent on others for their sense of self-worth. They become hypersensitive to slights. In the most extreme cases, their envy can prompt them to take sadistic pleasure in tormenting perceived enemies, and those they think are getting more respect than they are. In Trump’s case, his need to demonstrate over and over that he is worthy of admiration overwhelms his capacity to focus on nearly anything else.

While our elected officials and much of the news media have avoided the topic of Trump’s mental health, it is clear that our adversaries have carefully studied his psychological weaknesses and determined how to use them to their advantage, as we saw during his negotiations with Putin and Kim Jong Un. Ironically, our own intelligence community does just this sort of analysis about foreign leaders.

Trump’s grip on reality will likely continue to diminish as he faces increasing criticism, accusations, threats of impeachment and potential criminal indictments. We can expect him to become more desperate, more extreme in his comments, more violent in his threats, and more reckless and destructive in his actions. His latest extreme threat to Iran is one example, and he is likely to return to similar threats to North Korea if he feels that Kim Jong Un is making him look weak and unsuccessful.

So how can we hold onto our own mental health in the face of the danger Trump poses? First, don’t use logic or rationality to try to understand or counter Trump’s statements and behaviors. He is driven not by reason but by negative emotions that are infectious. Trump thrives on creating fear and sowing confusion. He lies without guilt. Don’t match his emotion with your own.

Second, be clearer than ever about your core values, beliefs and principles, and rely on them for guidance and comfort, especially when you are feeling most triggered and fearful. Challenge every day the natural inclination to feel overwhelmed, fatigued or numb in the face of Trump’s behavior. This is what people with his psychological inclinations count on. Trump is aware that whatever he says repeatedly—no matter how outrageous—many people are more likely to believe, or at least to stop resisting.

Lastly, recognize that fear is your enemy. Holding onto the opposites of realism and optimism is the best antidote. James Stockdale, a Navy vice admiral, was imprisoned for eight years in North Vietnam and tortured repeatedly. What he said afterward about how he survived is relevant for anyone dealing with feelings of helplessness and hopelessness: “You must never confuse faith that you will prevail in the end—which you can never afford to lose—with the discipline to confront the most brutal facts of your current reality, whatever they might be."