Biological Roots of Sociopathy

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PROFESSOR JAMES FALLON: I spent a lot of my research career looking at different brain abnormalities, mostly schizophrenia, but also depression and addictions of different sorts. And then, my colleagues started to do something different.

NARRATOR: They asked him to analyze a variety of brain scans. What he didn't know was that some of them were the brain scans of murderers.

PROFESSOR JAMES FALLON: They brought me these scans and said, what do you think of these? What do you see? There were normals mixed in, people with schizophrenia, depression, and there were killers. But I didn't know the mix, or who, what, it was just like, here it is.

About halfway through, I started to notice a pattern that was fascinating. This one group, no matter what other damage they had or didn't have, they always had damage of the orbital cortex, right above the eyes. The other part of the brain that looked like it wasn't working right was this front part of the temporal lobe, which houses the amygdala. And that is where you're different animal drives are.

Suddenly I thought, this is extraordinary. So I separated out the piles, and I said, this is a different group. And bingo, when we broke the code, there it was. That group were the killers. And I was—it was really, you know, one of those aha moments.

NARRATOR: The areas that looked abnormal were crucial for controlling impulsivity and emotions.

SCIENTIST: Once we had determined that there are certain differences in brain function and structure, the next question is, how did they originate? From where do they come? And that brings up the question of genetic factors. All behavior, all physical features have strong genetic contributions.

NARRATOR: The search was on. Were there genes that linked to violence? In 1993, the breakthrough came with one family's history. Here, all the men had a background of violence, and all lacked the same gene.

PROFESSOR JAMES FALLON: There was one gene that was missing. And this was in the men. And all these men were violent. What was important was that the loss of one gene profoundly affected behavior. So that kind of supported the idea that one gene really controlled their behavior.

NARRATOR: It then emerged that just being born with one variant of this gene could also predispose you to violent behavior. The MAOA gene became known as the "Warrior" gene. At a regular family party, a casual remark by his mother took him by surprise.

MRS. FALLON: What did he say? As we were discussing this in different brains, I said to him, well, you should look into your own history. And I said, did you ever hear of Lizzie Borden? And I started to tell the story about Lizzie Borden, and how she had murdered her father and mother.

I said, there's a cousin of yours. Well, he was shocked. And of course, started to delve a little further into this.

PROFESSOR JAMES FALLON: I mean, it was really pretty startling. But you know, I knew it was true, because she just—she doesn't make things up.

MRS. FALLON: Yeah, there were quite a few murderers in that family.

PROFESSOR JAMES FALLON: At least 16 murderers in the one line.

NARRATOR: Hearing this, Jim took the bold decision to run a check on the entire family for the genes and brain structure linked to violent psychopathic behavior. The results of the brain scans came back first.

PROFESSOR JAMES FALLON: Now there's many, many shades, and they all looked normal. It was like, oh, this is fantastic. And then I came to one, and it was the last one, as it turns out, and it looked very abnormal. And this particular PET scan had no orbital cortex activity. It had no temporal lobe activity.

This whole sort of limbic system was not functioning. And I said, oh, my god. This is one of these killers. It's the exact same pattern as a killer. But when I look down at the code, it was not one of the killers, it was me. It was really a shock. It was a shock. But, you know, I try to make—you know, it was like, that's really interesting. Now I'm not in jail and I haven't killed anybody, I haven't done any of that stuff.

I said, at least I don't have the genes, I don't have that, you know? I just had the brain pattern. I said, OK, I felt better.

NARRATOR: He then did the gene tests, looking not only for the warrior gene, but for other traits, like impulsivity, that make up the profile of a psychopath. Back came the results.

PROFESSOR JAMES FALLON: And again, everybody had a mix of things in our family. It looked like an average sort of mix of these different genes that would have to due with aggression and all sorts of behaviors. Except, now again, there was this one that showed all of these high risk genes. And it was mine.

It was like, what are the odds of getting these? To throw the dice 20 times and come up six six, six six, six six? You know, it's millions to one.

NARRATOR: Now Jim started asking himself some unsettling questions.

PROFESSOR JAMES FALLON: This really became probably more serious in my mind, because it's like oh who am I, really? I mean, people with far less dangerous genetics become killers and are psychopaths, than what I had. You know, I had like almost all of them.

NARRATOR: But the reaction from his family was to unsettle him even further.

DIANE FALLON: It was surprising, but it wasn't surprising, because he really is, in a way, two different people. Even though he's been always very funny and gregarious and everything else, he's always had a standoffish part to him. And that's always been there. That's always been there.

PROFESSOR JAMES FALLON: Who isn't here. So we'll drink to Shannon, who's not here.

NARRATOR: Having heard what his family thought, Jim felt forced to be honest with himself.

PROFESSOR JAMES FALLON: Those are full pork, I think.

I have characteristics or traits, some of which are—that are psychopath, yeah. I could blow up an aunt's funeral if I thought it was a party that day. I would just take off. And that's not right. The thing is, I know that now, but I still don't care. And so I know something's wrong, but I still don't care. And you know, the nut—so I don't know how else to put that. It's just, you're in a position where, oh, that's not right. And I don't give a shit. And that's the truth.

NARRATOR: But Jim still had a puzzle to solve. If he had the brain and the genes of a killer, why wasn't he one? The answer is that whether genes are triggered or not will depend on what happens in your childhood. Simply having the warrior gene doesn't necessarily mean you'll be violent.

PROFESSOR JAMES FALLON: If you have the, so-called, high risk form of the gene, and you were abused early on in life, your chances of spending a life of crime are much higher. If you have the gene, the high-risk gene, but you weren't abused, then there really wasn't much risk. So just the gene by itself, the variant, doesn't really dramatically affect behavior.

But under certain environmental conditions, a big difference. And that was a very profound finding. It turns out that I had an unbelievably wonderful childhood. Then I went back and looked at old movies and old, you know, old pictures, and I'm smiling and then just happy as a lark. And it's just, you could see it kind of all the way through my life. You know, there's a good chance that offset all these genetic factors, the brain development, and everything.