High energy, drive, sleeplessness, grandiosity, a compulsion to talk a lot, and extraordinary self esteem are definitely part of it. At my highest levels of hypomania, I was driven towards a goal where I felt like it was the singular purpose that my whole life was converging towards, I was the one person in the world that could best accomplish it, and it was something the world desperately needed. That is certainly Trump right now.
Hypomania is a clinical condition that can turn to full psychotic mania for people predisposed to that, which I've never come close to fortunately, but it's also on a spectrum of normal behavior that can't just be called crazy. There are a lot of different pros and cons to being hypomanic, and an interesting book was written on the pros, The Hypomanic Edge: The Link Between (A Little) Craziness and (A Lot of) Success in America (edit: and the author of that book wrote the article you referenced, I should have read it closer first). For example, the author of this book surveyed leaders in Silicon Valley and they almost universally agreed that the clinical description of hypomania matched what they thought was needed from the most successful startup CEOs.
Bipolar people also deal with very humbling depression on the other side that makes them deeply empathetic to balance out the mania. Trump seems unipolar and to have not benefited from that. A couple more books that talk about this balance are A First-Rate Madness: Uncovering the Links Between Leadership and Mental Illness andLincoln's Melancholy: How Depression Challenged a President and Fueled His Greatness. These books I've referenced talk about former presidents and political figures among others that showed strong signs of hypomania, bipolar, or unipolar depression. Lincoln's crushing depression absolutely shaped him and experiencing that sort of pain gives you a lot to draw on to feel other's pain, like slaves. Trump's lack of empathy is startling. Hitler appears to have been bipolar and to have abused amphetamines to treat his depression which made his mania far worse.
Trump is a mixed bag of conditions. He has a short attention span, lack of curiosity, short fuse, narcissism, and sociopathy. When he's up all night lately as far as we can tell he spends his time watching CNN and Fox News, listening to what everyone's saying about him, getting angry then tweeting, and chasing tail, not educating himself. I can say I'm the opposite of Trump there, and when I'm up all night I'm often pouring through technical books or writing code trying to create something. If Trump had fewer negative psychological traits and more positive ones he could likely put his hypomania to good use, but he's not. Though, to his credit he's also clearly poured a lot of energy into his businesses, but he's running for president now.
I watched Trump's recent West Palm Beach rally where he went full conspiracy theorist demagogue denying the allegations of his accusers. He seemed quite inspired and grandiose, not defeated or depressed. His speech was much more focused and eloquent than we've come to expect. That would all fit with him being in a state of hypomania, and I'm afraid of what this is going to turn into as he keeps becoming more angry, disconnected from reality, and taking his followers further down his crazy path.
Mental health is far from simple. Too many people just think of separate groups of the crazy and non-crazy in the world. I'm really pleased to hear Hillary and others saying that we need to treat mental health and physical health as being on the same level. They're tangled together far more than people realize.