According to the book, Ryan was caught off guard when Trump won the election in an enormous upset over Democratic nominee Hillary Clinton. Republicans controlled the House and Senate, and Ryan, realizing that he would have to work with Trump, started researching how to deal with someone who is “amoral and transactional,” the book says.

A wealthy doctor in New York, who was also a Republican donor, contacted Ryan later and told him, “You need to understand what narcissistic personality disorder is,” according to the book.

“What?” Ryan asked, at which point the doctor sent the Wisconsin Republican an email detailing his “thoughts on how to best deal with a person with anti-social personality disorder,” Woodward and Costa reported. The email also included links to articles about the topic in The New England Journal of Medicine, and information from the International Statistical Classification of Diseases and Related Health Problems, 10th edition.

The book said that “Ryan studied them for weeks, convinced Trump had the personality disorder.”