Here's what it's like to be married to a psychopath

You might have a lot of preconceived notions about what it's like to meet a psychopath, but now imagine being married to one.

James Fallon, a neuroscientist at the University of California Irvine School of Medicine, accidentally found out he was a psychopath while studying the brain scans of psychopathic criminals and realizing his own brain looked eerily similar.

Fallon later discovered other disturbing clues about himself: Not only did he possess certain genes that have been linked to psychopathy, but he had half a dozen alleged murderers (including the infamous Lizzie Borden) in his family.

In interviews, Fallon comes across as a perfectly normal, affable guy. But what would it be like to live with him, we wondered?

What it's like to live with a psychopath

The BBC interviewed Fallon and his family in a show called "The Brain of a Murderer: Are You Good or Evil?" in 2013. The show paints a telling portrait of his personality.

Fallon's wife, who declined to be interviewed for this story, admits that she wasn't hugely shocked when her husband found out he had some neurological and genetic traits linked with being a psychopath.

"It was surprising, but it wasn't surprising, because he really is, in a way, two different people," James Fallon's wife, Diane Fallon, says in the video. On the one hand, she said, there's the guy who's funny and gregarious. But on the other hand, he's always had "a stand-offish side."

Fallon's son James echoed his mother's statements as well.

"I knew there was always something off" about him, his son James says in the video. Once he'd learned his father had some traits linked with psychopathy, his son added: "It makes more sense now." In addition, he says his father has a hothead - a trait associated with a subtype of psychopaths Fallon calls distempered psychopaths.

Despite these accounts, there's a good reason that we shouldn't jump to negative conclusions about people like Fallon. For one thing, having psychopathic traits doesn't necessarily make someone a bad person, says Fallon, since personality isn't driven by genes or brain chemistry alone.

Psychopaths aren't always criminals

In interviews, Fallon reveals that he does bear some of the behavioral traits of a psychopath, such as a lack of emotional sensitivity toward others. In his interview with BBC, Fallon admits that he'd probably blow off the funeral of a family member so he could go to a party or do something more fun instead.

But Fallon certainly isn't a criminal - a fact he credits to the positive environment in which he grew up. Research has found that for some people who possess a gene linked to psychopathy, being abused or mistreated as a child can influence whether they develop antisocial behavior.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) doesn't recognize the term psychopath, but is has an entry for something called "antisocial personality disorder." People with this disorder, it says, exhibit impairments in personality functioning and pathological personality traits, including egocentrism, manipulative behavior, and a lack of empathy.

In fact, psychopathy is surprisingly common in the population, with estimates of its prevalence ranging from 0.2% to 3% (a 2009 study in the UK found a prevalence of 0.6%). Even in literature, psychopaths abound - it appears that Sherlock Holmes may have been one.

So chances are, you've probably met a psychopath. And who knows - it's not entirely outside the realm of possibility that you could even live with one!

You can watch the full BBC interview with Fallon and his family: