A lot of what laypeople learn about psychopaths is through cinema, despite psychopaths making up around 4.5 percent of the general population (or between 10 and 35 percent if you happen to be in prison).

How movies represent psychopaths shape people's view of them as a whole, so how accurate are the portrayals we see on screen? Well, a group of psychiatrists have spent three years watching 400 movies containing characters who could be described as psychopaths (by cinema-goers or within the films themselves) to determine which of them shows accurately the clinical condition of psychopathy.

Whittling the list down to 105 male and 21 female psychopaths portrayed on film since 1915, the team of 10 forensic scientists and movie critics then weighed in on who could be diagnosed as a psychopath, and whether they would in fact be diagnosed with other conditions. The team found some excellent and compelling portrayals of psychopathy that they believe could be used for "teaching and illustrating several aspects of forensic psychiatry". These, however, were in the minority.

"Some of the most famous 'psychos' in films are not psychopaths, but psychotics," the team wrote in their 2013 paper, published in the Journal of Forensic Sciences. 

"Well-known examples of these are found in the films Psycho (Norman Bates) and Taxi Driver (Travis Bickel). These characters are, in varying ways, disconnected from reality and suffer from delusional ideation."

One of the best portrayals of psychopaths, according to the team, was Anton Chigurh, the antagonist in the Coen brothers' No Country for Old Men. 

"Anton Chigurh is a well-designed prototypical idiopathic/primary psychopath, the team wrote.

"We lack information concerning his childhood, but there are sufficient arguments and detailed information about his behavior in the film to obtain a diagnosis of active, primary, idiopathic psychopathy, incapacity for love, absence of shame or remorse, lack of psychological insight, inability to learn from past experience, cold-blooded attitude, ruthlessness, total determination, and lack of empathy. He seems to be effectively invulnerable and resistant to any form of emotion or humanity."

Other good portrayals of psychopaths were Henry from Henry-Portrait of a Serial Killer, which was itself inspired by real-life serial murderer Henry Lee Lucas.

"In this film, the main, interesting theme is the chaos and instability in the life of the psychopath, Henry’s lack of insight, a powerful lack of empathy, emotional poverty, and a well-illustrated failure to plan ahead."

Some of the most famous film psychopaths do not live up to what the psychiatrists would see in real life. Hannibal Lecter, who they call the most famous and "caricatured" example of a psychopath, is described as having "many personal characteristics that are not generally found in everyday clinical practice".

Overall, the team believed that though many depictions of psychopaths are not accurate to clinical descriptions of the condition, films that show psychopaths can be useful to society.

"These characters, which mirror some types of our society, are very important for the cinema itself and art in general but mostly for future generations of forensic psychologists and psychiatrists as pedagogic materials," they conclude.

"In fact, some of these fictional characters can be considered valuable for teaching and illustrating several aspects of forensic psychiatry, such as personality disorders, paraphilia, expert witness characteristics, portrayal of the legal system, behaviors of the lawyers, and courtroom procedures. Moreover, these movies can be sources of lessons, questions about clinical cases and lead to discussions between students and faculty members."