The U.S. government reached alarming conclusions about the personal character of North Korean leader Kim Jong Un based on interviews with people who knew him when he was a student in Switzerland, former U.S. Secretary of State for East Asian and Pacific Affairs Kurt Campbell revealed on CNN over the weekend.

The official U.S. assessment of Kim's character is perhaps not, on its face, very surprising. After all, the North Korean leader, like his father, certainly gives the impression of a wild-eyed despot who appears to buy into his own highly official cult of personality. But North Korea-watchers have long debated whether this is merely a pose, a performance calculated to rally North Koreans and intimidate the outside world. This assessment suggests that Kim's antics are not entirely about rational decision-making but are at least in part driven by a personality just as crazy as it appears.

Reports have long conflicted over how much time Kim spent as a study-abroad student in Switzerland, where he posed as the son of a driver for the local North Korean embassy. Most reports suggest he attended Swiss boarding school between 1998 and 2000, when he would have been 15 to 17 years old, although Campbell asserts that he "spent seven or eight years out of North Korea in Switzerland."

"We went to great pains to interview almost everyone – classmates, others – to try to get a sense of what his character was like," Campbell said. "The general recounting of those experiences led us to believe that he was dangerous, unpredictable, prone to violence and with delusions of grandeur."

Campbell made the comments in the context of a discussion about the recent purge and execution of Jang Song Thaek, Kim's uncle and a long-time senior regime official. The former State Department official conceded that "we really do not know" the full story of the Jang purge or why it happened, which is also broadly true about the inner workings of the North Korean government.

We can't know what's happening inside the North Korean regime any more than we know what's happening in Kim's head. But if this assessment of his character is accurate, it has significant implications for this nuclear-armed rogue state, its threat to the outside world and the fates of its 25 million citizens.