What's the difference between sociopaths, psychopaths, serial killers, etc.?
Dear Straight Dope:
After watching one psychological thriller too many, I realized I had no idea what the real difference is between sociopaths, psychopaths, serial killers, and antisocial personalities. Some casual Internet research only yielded psychobabble. One Website mentioned that one percent of the population is psychopathic. Does this have anything to do with "natural born killers"? How many of our friends and neighbors will potentially hack us to bits with axes?
Well, I think after the first one you've pretty much seen your limit, but these are strange days. Let's see if we can at least get the terminology for these dangerous types straightened out.
The first thing to understand is that you're mixing up different types of terms here. "Serial killer" isn't a specific mental disorder but rather refers to a pattern of killing defined by statute — specifically, 28 U.S.C. § 540B (link), which authorizes the FBI to investigate such crimes:
Serial killings.— The term “serial killings” means a series of three or more killings, not less than one of which was committed within the United States, having common characteristics such as to suggest the reasonable possibility that the crimes were committed by the same actor or actors.
In a similar vein, I found a 1998 report (link) that categorizes homicides by number of victims, number of locations, number of events, and whether there was a cooling off period between killings. Single, double, triple, and mass murders are all killings that involve one location, one event, and no cooling off period (mass murder is the catch-all for murders with four or more victims). Spree murders involve more than one victim and more than one location, without a cooling off period. Serial killings involve multiple killings, events, and locations, plus a cooling off period between killings.
The other terms you mention are psychiatric diagnoses or constructs used by criminologists attempting to predict or explain criminal behavior. The only one currently an official psychiatric diagnosis is antisocial personality disorder (APD). This term replaced "sociopath" and only applies if (link):
A. There is a pervasive pattern of disregard for and violation of the rights of others occurring since age 15 years, as indicated by three (or more) of the following:
(1) failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are grounds for arrest
(2) deceitfulness, as indicated by repeated lying, use of aliases, or conning others for personal profit or pleasure
(3) impulsivity or failure to plan ahead
(4) irritability and aggressiveness, as indicated by repeated physical fights or assaults
(5) reckless disregard for safety of self or others
(6) consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations
(7) lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another
B. The individual is at least age 18 years.
C. There is evidence of Conduct Disorder with onset before age 15 years.
D. The occurrence of antisocial behavior is not exclusively during the course of Schizophrenia or a Manic Episode.
A 2005 study published in The Journal of Clinical Pyschiatry (link) found that about 3.6% of Americans will be diagnosed with APD sometime during their lives. Of course, not everyone with APD is a serial killer, for which I guess we should be grateful, and not all serial killers have APD.
Though not listed in the Diagnostic and Statistical Manual of Mental Disorders, the official catalogue of mental illness, "psychopath" continues to be used by some criminologists. Gennaro Vito and his colleagues in their textbook on criminology note that the term was coined in 1845 (link). Canadian psychologist Robert Hare has revived the term to describe the criminal personality. He created a psychological scale that purports to measure psychopathy. His checklist requires a trained interviewer to rate a subject on:
Factor 1: "Aggressive narcissism"
Grandiose sense of self-worth
Lack of remorse or guilt
Callous/lack of empathy
Failure to accept responsibility for own actions
Promiscuous sexual behavior
Factor 2: "Socially deviant lifestyle"
Need for stimulation/proneness to boredom
Poor behavioral control
Lack of realistic, long-term goals
Early behavior problems
Many short-term marital relationships
Revocation of conditional release
Traits not correlated with either factor
Many short-term marital relationships
Hare's theory remains controversial, but a high score on his test is at least moderately correlated with both recidivism and violent criminality. Hare estimates 15 to 25 percent of prisoners and 1 percent of the general population are psychopaths. But not all psychopaths are violent criminals. For example, Hare's most recent book, Snakes in Suits: When Psychopaths Go to Work (2006), suggests that psychopaths thrive in corporate and similar environments without killing people — a conclusion many veterans of the business world will find hard to argue with.
Regarding the relationship between psychopaths and those with APD, Hare says, "Some with APD are psychopaths, but many are not. The difference between psychopathy and antisocial personality disorder is that the former includes personality traits such as lack of empathy, grandiosity, and shallow emotion that are not necessary for a diagnosis of APD. APD is three or four times more prevalent in the general population and in prisons." He also notes, "Just having a psychopathic personality does not make one a criminal. Some psychopaths live in society and do not technically break the law. Some may lead seemingly normal lives, not hurting people in ways that attract attention, but causing problems nonetheless in hidden economic, psychological, and emotionally abusive ways." In other words, they're not nice people, and if they decided it was in their interest, they'd probably kill you, but they'd probably rather screw you out of your raise and steal your wife.
How many serial killers are out there right now? Estimates for the United States range from 35 (FBI, 1990) to 200 or more (Ronald and Stephen Holmes, Murder in America, 2001) — something to think about next time you see that guy two cubicles over with a funny look in his eye.
American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (2000)
Babiak, Paul and Hare, Roberd, Snakes in Suits: When Psychopaths Go to Work (2006)
Compton, Wilson, et al., "Prevalence, Correlates, and Comorbidity of DSM-IV Antisocial Personality Syndromes and Alcohol and Specific Drug Use Disorders in the United States: Results From the National Epidemiologic Survey on Alcohol and Related Conditions," Journal of Clinical Psychiatry, 66: 677-685 (2005)
Endrass, Jérôme, "Predicting violent infractions in a Swiss state penitentiary: A replication study of the PCL-R in a population of sex and violent offenders," BMC Psychiatry, 8:74 (2008)
Hare, Robert and Neumann, Craig, "Psychopathy as a Clinical and Empirical Construct," Annual Review of Clinical Psychology, Vol. 4: 217-246 (2008)
Holmes, Ronald and Holmes, Stephen, Murder in America (2001)
Vito, Gennaro, et al., Criminology: Theory, Research, and Policy (2007)