FHM sat down with serial-killer expert and criminologist Professor David Wilson to find out just how easy it is to spot a psychopath. And it appears it's actually quite tricky.
"They're going to be the person who is most attentive to your needs, always telling you how wonderful and brilliant they are."
Well, that doesn't sound so bad...
"But remember, this is a person who is going to be bringing you into their world so that they can then use you."
Here are three things to look out for if your new date/boss/next-door neighbour with a penchant for late-night gardening starts giving you the creeps...
01 They're perfect
"You’re dealing with someone who is very arrogant, manipulative and dishonest who has a great deal of glibness and grandiosity. They're often the life of the party.
"The advice I always give is, if this person seems too good to be true, then they probably are. Be very careful."
02 They're more likely to carry a briefcase than a butcher's knife
"Psychopaths don’t need to be violent. The prison population will have a higher percentage per capita than the general population, but that doesn’t mean to say a psychopath will have a criminal record.
"In fact, some of the characteristics of psychopathy also allow people to be very successful in business. If you don’t have empathy then you'll find it much easier to claim other people's work as your own, or to sack them."
03 They're not the lonely weirdo in the corner
"Psychopaths are very impulsive, very irresponsible, very sensation-seeking. For this reason, they'll often have multiple sexual partners and will start new relationships before they've ended old ones.
"The more people you can gain access to when you’re a psychopath, the more potential you will have to be able to use that person for your own advantages."
For even more mind-blowing (but fictional) psychopath stuff, check out The Following: The Complete First Season, out now on Blu-ray and DVD.