James Fallon is a happily married father of three, an award-winning neuroscientist at the University of California, Irvine, the founder of several successful biotech companies, and a scientific advisor to the US Department of Defense. He is also a psychopath.

In 2005, after decades of studying the brain scans of psychopathic killers, Fallon made a startling discovery when examining his own PET scan as part of a separate research project. His brain, Fallon discovered, looked precisely like those of the cold-blooded murderers he’d spent the last 20 years scrutinizing. And after analyzing his DNA, Fallon later uncovered that his genetic profile contained several genes strongly linked to violent, psychopathic behaviors.

After Fallon revealed the findings in a 2009 TED Talk, mainstream media latched on: he was profiled on NPR, graced the front page of the Wall Street Journal, and even inspired an episode of the TV series Criminal Minds. Now, however, Fallon is telling his own version of the story. In a new book, The Psychopath Inside (Penguin Group), Fallon takes a hard scientific look at our evolving understanding of psychopathy — through the lens of his own biology and behaviors. And the latter, as he admits, haven’t exactly been laudable: Fallon isn’t a murderer, but he writes candidly of hard partying, perpetual lying, and reckless, dangerous impulsivity — not to mention the admission that he’s never truly made an empathetic connection (even with his wife). So how does an expert in psychopathy come to terms with the disturbing symptoms of his own illness? We talked to Fallon to find out.

I think you’d agree that the term “psychopath” is thrown around liberally, and the general public tends to think of psychopathy as a condition that afflicts the most cold-blooded of killers. But you point out in the book that, as far as the medical community is concerned, psychopathy isn’t even a defined and diagnosable illness. Why do you think that is?

You’re right that there are a lot of definitions of psychopathy, and there isn’t one governing set of symptoms that point to it. If you look to the DSM-5 [ED: Diagnostic and Statistical Manual of Mental Disorders] psychopathy doesn’t exist, and if I asked my psychiatrist friends they’d agree with that assessment. In large part, that’s because many of the traits that characterize a psychopath — things like narcissism, sadism, anti-social behavior — appear in other disorders. So there isn’t a clean set of defining traits we can look to and come up with a diagnostic criteria. Really, that’s how much of psychiatry has turned out to be: we don’t have categorical answers, because there’s much more dimensionality to these conditions.

"I might have a lot of weird, disturbed thoughts, but I don’t act on those thoughts."

As far as public perception goes, I’d say that the best, most badass, sadistic, ultimate example of a psychopath would be the original Hannibal Lecter. That’s who we think a psychopath is. But I’d argue that Will Graham, the FBI agent who tracks Hannibal, is the version of a psychopath we see more often in reality: he’s the pro-social psychopath, the guy in the office who seems a little off but who doesn’t engage in really ugly, egregious criminal behavior. And that’s where I would put myself. I might have a lot of weird, disturbed thoughts, but I don’t act on those thoughts. The Hannibal guys are a small subset, but they’re certainly overrepresented in the media.

So if you personally aren’t the Hannibal, then what kind of psychopath are you?

What I’ve realized is that for me, it’s all about the power. I get a buzz from manipulating people, and from making them want to do things for me — even if I don’t take it that far, by making unreasonable or immoral demands on them. I just like to know that I can; it’s like a game I play whenever I walk into a room. I can really turn on the charm, I can really work it to get whatever it is that I might want. I mean, I don’t look good: I’m fat and I’m old. But I can make people think that I’m really special. And that gives me a hit that I crave.

Look, let’s say all of a sudden I was broke, I didn’t have a career, I didn’t have a family. Then I could see myself breaking the codes of ethics and morality, and getting into some ugly behavior to get what I wanted or felt I needed. But I’ve been very fortunate to have a wonderful, privileged life — so I don’t feel a need to break those codes. I’m just saying that I can easily see myself going there.

As a scientist, you were a long-time adherent to the idea of genetic determinism: that our biology rather than our environment decides how we wind up. But you write that finding out you had the genetic profile of a psychopath actually changed that perception. How so?

At the period of time when I was growing up and going to school, everything was about society and your environment, and how those things molded you. I guess for me, I looked around and knew a lot of great poor people and a lot of really rich jerks, so I said “hey, if the environment is key to all of this, it really isn’t doing the job we think it is.” Instead, I became convinced that we were born and not raised — and I spent my career studying exactly how the brain influences who we become.

"Your environment can play a role in which genes are turned on or off."

But I didn’t fit my own theory. I had similar brain scans to full-blown, psychopathic killers. I had the genetic profile of a psychopath too. So why didn’t I fall into that kind of behavior? Well, I’d say it’s because I had a very fortunate, very warm upbringing with a wonderful family. And a lot of those who have my same genetic makeup and go onto violence endured awful abuse or trauma. So you need to give environment more credit than I used to, but that doesn’t mean I’ve thrown out biology: around the time this was all happening to me, the field of epigenetics started to explode. Maybe it isn’t that biology doesn’t determine who you are, but that your environment can play a role in which genes are turned on or off.

You’ve known about your brain scans for four years, but writing this book forced you to discuss those results with others, to confront unpleasantries about your personality, and to acknowledge how your behavior has impacted your family, friends, and colleagues. What was that process like?

Coming to terms with the hurt you’ve caused loved ones or close friends, that’s not an easy thing to do. I had never given much thought to my behavior, I thought it was entirely fine — but I guess you never know what people are saying about you behind your back. And when I started asking people to really be honest with me, they were, and they told me “You know Jim, a lot of the time you’re kind of an asshole, or you’re really inconsiderate.” My brother-in-law, who’s a Vietnam vet, told me that of all the stuff he did in the war, none of it compares to the risks he took when he was hanging out with me.

The most important part of all this has been reexamining my life with my family, and my behavior towards them. And I’m very fortunate, because at the end of the day despite everything, they still think that deep down I’m a pretty good guy. My professional pride is very important to me too, and for the most part colleagues treat me the same as they used to and still trust my judgment. But I’ll admit that a couple people don’t want to be around me anymore, one in particular has simply fled from me — they reinterpreted their interactions with me after the psychopathy stuff came out, and they weren’t okay with me.

Now that you’ve recognized the effects of your behavior, have you been able to change it?

Well, my wife just walked in, so let’s ask her. [“It’s Katie Drummond from The Verge, she wants to know if this has all made me any better.”] She says, “Yes, you’re more considerate.” So there you go.

"It’s just the day-to-day decision to not be an asshole."

I did make an effort to change my behavior during this process, and I’ve kept up with that. I decided to start doing all the things people think are “the right things to do.” I go to the weddings, the funerals, I think about people’s feelings — all the stuff I don’t get a kick out of, I try to do now. It’s just the day-to-day decision to not be an asshole, to not lie to get out of something so that I can go down to the bar. And I don’t do it because I’m nice, I do it because of my pride: I want to know if I can pull it off. Trust me, there’s no magic to it. As I’m becoming a nicer guy, I’m also getting fatter. I can only control so many impulses at once.

Let’s say someone reading your book — and I’m asking for a friend here — is worried that they exhibit a lot of the same traits you do. Maybe they seek out power, they’re manipulative, they don’t readily make emotional connections. Do you have any advice for readers concerned they, too, might be “pro-social” psychopaths?

Well, I can only tell you what worked for me. Since I’m a lapsed Catholic, I started thinking of psychopathic behavior in terms of the seven deadly sins. Those sins, to me, are just psychopathic traits and tendencies with different names — I kept sinning, and I kept doing it over and over and over. And using the term “sin” is one example of how we’ve all mollified psychopathic behaviors: if it’s a sin, well then that’s okay, because everyone sins and then you go to church on Sunday and you make it better. But it’s not actually okay.

I’d say that around 10 or 15 percent of us are pretty borderline as far as psychopathy goes, but we all let those behaviors slip and we protect each other — we say “oh, it’s okay, he does that all the time,” or “oh, that’s just how she is.” It’s a Stockholm Syndrome epidemic. What I’d tell you to do is strip away the bullshit terms and excuses surrounding your behavior, and ask yourself what you’re actually doing and how it affects other people. For me, simple linguistics were what it took to change my behavior. Instead of saying, “Oh, that’s a sin and I gotta go to church,” it’s a matter of saying “Oh wow, I just did something really psychopathic, and I gotta figure out how to stop it.”