Many forensic psychologists, psychiatrists and criminologists use the terms sociopathy and psychopathy interchangeably. Leading experts disagree on whether there are meaningful differences between the two conditions. I contend that there are clear and significant distinctions between them.
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), released by the American Psychiatric Association in 2013, lists both sociopathy and psychopathy under the heading of Antisocial Personality Disorders (ASPD). These disorders share many common behavioral traits which lead to the confusion between them. Key traits that sociopaths and psychopaths have in common, include:
In addition to their commonalities, sociopaths and psychopaths also have their own unique behavioral characteristics, as well.
Sociopaths tend to be nervous and easily agitated. They are volatile and prone to emotional outbursts, including fits of rage. They are likely to be uneducated and live on the fringes of society, unable to hold down a steady job or stay in one place for very long. It is difficult but not impossible for sociopaths to form attachments with others. Many sociopaths are able to form an attachment to a particular individual or group, although they have no regard for society in general or its rules. In the eyes of others, sociopaths will appear to be very disturbed. Any crimes committed by a sociopath, including murder, will tend to be haphazard, disorganized and spontaneous rather than planned.
Psychopaths, on the other hand, are unable to form emotional attachments or feel real empathy with others, although they often have disarming or even charming personalities. Psychopaths are very manipulative and can easily gain people’s trust. They learn to mimic emotions, despite their inability to actually feel them, and will appear normal to unsuspecting people. Psychopaths are often well educated and hold steady jobs. Some are so good at manipulation and mimicry that they have families and other long-term relationships without those around them ever suspecting their true nature.
When committing crimes, psychopaths carefully plan out every detail in advance and often have contingency plans in place. Unlike their sociopathic counterparts, psychopathic criminals are cool, calm, and meticulous. Their crimes, whether violent or non-violent, will be highly organized and generally offer few clues for authorities to pursue. Intelligent psychopaths make excellent white-collar criminals and "con artists" due to their calm and charismatic natures.
The cause of psychopathy is different than the cause of sociopathy (1). It is believed that psychopathy is the largely the result of “nature” (genetics) while sociopathy is more likely the result of “nurture” (environment). Psychopathy is related to a physiological defect that results in the underdevelopment of the part of the brain responsible for impulse control and emotions. Sociopathy, on the other hand, is more likely the product of childhood trauma and physical/emotional abuse. Because sociopathy appears to be learned rather than innate, sociopaths are capable of empathy in certain limited circumstances but not in others, and with a few individuals but not others.
Psychopathy is the most dangerous of all antisocial personality disorders because of the way psychopaths dissociate emotionally from their actions, regardless of how terrible those actions may be. Many prolific and notorious serial killers, including the late Ted Bundy and John Wayne Gacy, and the incarcerated Dennis Rader ("Bind, Torture, Kill" or BTK) are unremorseful psychopaths. Psychopathic killers view their innocent victims as inhuman objects to be tormented and exterminated for their own amusement or even sexual gratification.
Contrary to popular mythology, most serial killers are not mentally ill in either a clinical or legal sense nor are they "evil" geniuses. At least 40 percent of all serial killers are unrepentant psychopaths. See my related article on that topic.
(1) Bouchard, T.J., Jr., Lykken, D.T., McGue, M., Segal, N.L. and Tellegen, A. 1990."Sources of human psychological differences: The Minnesota Study of Twins Reared Apart." Science 250 (4978), pp. 223–228.