Donald Trump doesn't have clear contact with reality, though I'm not sure it qualifies as a bona fide delusion. He needs things to be a certain way even though they aren't, and that's one reason he lies. There can also be a conscious manipulative element to it. When he put forward, and politically thrived on, the falsehood of President Obama's birth in Kenya, outside the United States, he was manipulating that lie as well as undoubtedly believing it in part, at least in a segment of his personality.

I did the first study because I had been exposed to something that I took to be important and interesting - this thought reform process - in the military.

One reason that I embarked on a study of Nazi doctors was that in this personal journey, I had the feeling increasingly that I did want to do a Holocaust study and that increasingly I wanted it to be of perpetrators, which I thought was more needed.

As a kid I was fascinated with sports, and I loved sports more than anything else. The first books I read were about sports, like books about Baseball Joe, as one baseball hero was called.

For anyone with the traits - of feeling himself victimized, of seeking to be the strongman who resolves everything, yet sees truth only through his own self and negates all other truth outside of it - is bound to become more malignant when he has power. Power then breeds an intensification of all this because the power can never be absolute power - to some extent it's stymied - but the isolation while in power becomes even more dangerous. Think of it as a vicious circle. The power intensifies these tendencies and the tendencies become more dangerous because of the power.

But I spent just two calendar years at Cornell University, though it was covering more than three years of work, and then went to medical school and did become interested in psychiatry, and even helped form a kind of psychiatry club in medical school.

While Donald Trump doesn't have any systematic ideology, he does have a narrative, and in that narrative, America was once a great country, it's been weakened by poor leadership, and only he can make it great again by taking over. And that's an image of himself as a strongman, a dictator. It isn't the clear ideology of being a fascist or some other clear-cut ideological figure. Rather, it's a narrative of himself as being unique and all-powerful. He believes it, though I'm sure he's got doubts about it.