Antisocial Personality Disorder vs. Psychopathy

Serial Killers is a subject that nowadays appears in every newspaper and in some point in normal conversations. But, what is in fact a serial killer? How can you distinguish it from simple antisocial personality disorder?
A study published by Discovery Investigation had explored this subject, here's what they say about this controversy:

"Mental health professionals use the Diagnostic and Statistical Manual of Mental Disorders (DSM), developed by the American Psychiatric Association, to understand the illnesses of their patients and how to treat them. The DSM doesn't list serial murder among the 300 known mental disorders catalogued in its pages. It does, however, describe antisocial personality disorder, or ASPD. It's this condition that describes the behavior of many serial killers.
To understand ASPD, it helps to review the DSM criteria used to diagnose it. The most obvious indicator of the disorder is a total disregard for laws and social norms. People with ASPD have a long history of arrests and are often involved in physical fights or assaults. Some are capable of lying, cheating and deceiving so skillfully it is difficult to know when they are telling the truth or lying. They also act impulsively, with little care given to the safety of themselves or others.
To be diagnosed officially with ASPD, a person must be 18 years old, but symptoms generally begin to appear earlier, sometimes in the early teens. Adults with ASPD struggle to stay employed and, as a result, often have financial problems, according to the DSM. The manual also mentions that the disorder occurs more frequently in men than women — about 3 percent versus 1 percent.
Experts describe psychopathy as a more severe form of ASPD. Psychopaths have the antisocial symptoms just mentioned, but they also have additional traits that make them especially difficult to diagnose and treat. Chief among these traits is a lack of remorse or guilt for their actions. They also tend to be highly paranoid and suspicious.
Robert D. Hare of the University of British Columbia, a pioneer in the field, developed a diagnostic tool for psychopathy that measures the same antisocial symptoms as the DSM, but also evaluates interpersonal criteria, such as lack of empathy and shallow emotions. The tool is known as the Hare Psychopathy Checklist — a collection of 20 criteria that measure a person's antisocial behavior, emotional and interpersonal traits, and other factors.
The highest possible score is 40, but someone who scores 30 points is considered a psychopath, according to Kent Kiehl and Joshua Buckholtz, who explored the mind of a psychopath for Scientific American. Interestingly, the average score on the Hare Psychopathy is 4, write Kiehl and Buckholtz. That just means that psychopathy is a continuum, the way many other disorders are. It also means most psychopaths are not violent and are not destined to commit murder. A few, however, fall at the far end of the scale. These violent psychopaths may include serial killers."

So, hey you, be careful!