Features of other relevant concepts

Diagnostic features

To appreciate the key features and boundaries of narcissistic personality disorder, an understanding of antisocial personality disorder, as well as two overlapping traits, psychopathy and sociopathy, may be helpful.  According to the DSM V, individuals may be diagnosed with antisocial personality disorder if, since the age of 14, they have exhibited three of the following signs or symptoms, each of which demonstrate an inclination to disregard or violate the rights of other people:

• recurrent actions that violate laws or norms, such as theft or harassment, to the extent these acts may be grounds for arrest,
• repeated lying or deceit, often to seek money, sex, or power,
• impulsive actions or decisions, often without consideration of consequences, such as shifting jobs erratically,
• repeated assaults or fights, including at home,
• reckless disregard of safety, such as driving while intoxicated or substance abuse,
• an inability to work consistently or honour financial obligations, such as debts, with negligible remorse,
• indifference, rather than remorse, after hurting or mistreating someone, sometimes including a tendency to blame victims.

Nevertheless, individuals are not diagnosed with this disorder unless they are adults and had been diagnosed with conduct disorder before the age of 14—a disorder that entails aggression, destruction of property, deceit or threat, as well as serious breaches of rules.  Furthermore, if individuals exhibit these symptoms only during a bout of schizophrenia or bipolar disorder, they will not be diagnosed with antisocial personality disorder.

Other features

Individuals who are diagnosed with antisocial personality disorder often exhibit other tendencies or behaviours as well.  For example, these individuals

• tend to be cynical or contemptuous of the feelings or concerns of other people rather than empathic or compassionate,
• may seem opinionated or conceited and inflate their qualities,
• often display superficial charm and use many technical or sophisticated words to express themselves,
• seem irresponsible in relationship, such as fail to sustain romances or care for their children responsibly.

Antisocial personality disorder is observed in about 3.6% of the population, although six of the seven samples from which this figure was derived were US adults (Morgan & Zimmerman 2018).  About 70% of individuals diagnosed with antisocial personality disorder are men.  Some of the manifestations of antisocial personality disorder may subside after the age of 40 (Black, 2015).quiet ego scale has been validated in other settings and nations.  For example, Bernabei et al. (2024) validated this scale at an Italian university, in which the participants were 160 university students, ranging in age from 20 to 42.  The study revealed that a quiet ego was positively associated with measures of resilience, happiness, and psychological wellbeing.

Evolution of this term

Many people violate the norms of society and the rights of other people. In the 1920s and 1930s, George Partridge, an American psychologist, discussed the implications of this behaviour (Partridge, 1928; Partridge, 1930). He also ascribed these behaviours to problems in the social environment, such as parental rejection during childhood.  Consequently, he proposed the term sociopath to label these individuals (Partridge, 1930).

About a decade later, in his renowned book entitled “The mast of sanity”, Hervey Cleckley attempted to delineate the traits of psychopaths—a term that psychiatrists had used for many decades to describe people who often perpetrated unlawful, deceptive, impulsive, aggressive, risky, and callous behaviour.  Primarily derived from clinical observations of 15 individuals, he characterised these psychopaths as individuals who exhibited superficial charm but were callous and devoid of remorse or shame (Cleckley, 1941).

Therefore, during these decades, the terms sociopathy and psychopathy largely evolved from distinct strands of literature.  Yet, because these terms referred to overlapping and similar patterns of behaviours, both academics and practitioners often used the words sociopathy and psychopathy interchangeably. 

In 1952, the first edition of the DSM, however, utilised the term sociopathic personality disturbance to label people who breach the norms of society and the rights of other people.  This reference to sociopathy, rather than psychopathy, was preferred because of several reasons. First, as Robert Hare later discussed in his book “Snakes in suits”, the public sometimes confused the term psychopath and psychotic—a problem that other labels, such as sociopath, prevented.  Second, the DSM at this time primarily ascribed this behaviour to problems in the social environment.  Third, the behaviours were deemed as inappropriate if they violated rules that are socially constructed—such as laws or cultural norms.  In 1968, however, the DSM II refined the definition of this disturbance but labelled this pattern of behaviour as antisocial personality.   

Differences between sociopathy and psychopathy

Since this time, researchers and clinicians have generally regarded sociopathy and psychopathy as severe manifestations of antisocial personality disorder (Johnson, 2019).  About 30% of the individuals who are diagnosed with antisocial personality disorder also exhibit sociopathy, whereas about 3 to 15% of individuals who are diagnosed with antisocial personality disorder also exhibit psychopathy, although the precise figure depends on the definition of these characteristics. 

Because of this overlap with antisocial personality disorder, sociopathy and psychopathy are similar.  Despite their similarities, researchers often allude to several key differences (e.g., Gagne, 2024; Hare, 2006; Johnson, 2019; Pemment, 2013):

• generally, sociopathy is more likely to be largely ascribed to adverse events or experiences, such as child abuse, permissive parenting, or severe family dysfunction, that compromise socialisation; psychopathy is more likely to be ascribed primarily to biological aberrations at birth,
• people who exhibit sociopathy are more likely than people who exhibit psychopathy to establish close bonds with one collective, such as their family or a gang,
• whereas people who exhibit psychopathy experience negligible remorse, people who exhibit sociopathy may express some remorse in response to hurting their closest affiliates,
• people who exhibit sociopathy are more likely than people who exhibit psychopathy to be impulsive—and thus not as able to conceal their inclinations, maintain a job, or prevent incarceration,
• people who exhibit sociopathy are more likely than people who exhibit psychopathy are more prone to angry or violent outbursts,
• treatment of both disorders tends to be ineffective, but people who exhibit sociopathy seldom cooperate with treatment regimes, whereas people who exhibit psychopathy often feign changes in their behaviour.

Thus, in contrast to psychopathy, sociopathy is more likely coincide with some genuine relationships, albeit limited in number, some moral reasoning, as well as impulsive acts, sometimes compromising the capacity of these individuals to conceal their tendencies and avoid prison.

Nevertheless, in contrast to antisocial personality disorder and psychopathy, the definition and boundaries of sociopathy remain hazy.  That is, despite some variation and controversy, antisocial personality disorder can often be equated to the definitions and properties that appear in the DSM V.  Psychopathy can be equated to some common indices and scales, such as the renowned psychopathy checklist (Hare et al., 1990).  In contrast, researchers and practitioners have not developed a standard definition, taxonomy, or measure of sociopathy—although the socialisation scale from the California Psychological Inventory is one possible candidate, as Cooney et al. (1990) recommended in a study of alcoholics.

Acquired sociopathy

Typically, researchers ascribe sociopathy to adverse experiences during childhood.  However, as many case studies reveal, some people exhibit the hallmarks of sociopathy only after they experience brain injury, especially in the orbitofrontal cortex or related circuits (for an overview of this region, see Rolls, 2004).  This change in behaviour is often labelled acquired sociopathy (e.g., Blair and Cipolotti, 2000).

The most renowned example of acquired sociopathy is the case of Phineas Gage, a railroad worker, in the mid 1800s, whose personality transformed after a tamping iron, similar to a crowbar, penetrated his left frontal lobe (Harlow, 1848) and probably his ventromedial prefrontal cortex (Damasio et al., 1994)—a region that overlaps anatomically and functionally with the orbitofrontal cortex. Although perceived as intelligent and energetic before his injury, he was described as disrespectful, impulsive, obstinate, and profane afterwards (Harlow, 1868).  His indifference to social conventions is reminiscent of modern definitions of sociopathy.  As an aside, Phineas Gage may have recovered to be more responsible than often assumed (Macmillan & Lena, 2010).  For example, after his accident,

• for 7 years, he was employed as a coach driver in Chile, implying that he adapted to the language and social norms of the nation,
• towards the end of his life, a doctor, who had also known him before the accident, did not report any apparent impairment.

The term acquired sociopathy, however, was first applied many years later, to describe a patient who transformed from a successful person, with a solid marriage, to an individual who experienced failed marriages and businesses after his orbitofrontal cortex was damaged (Eslinger & Damasio, 1985).  These changes were observed even though his intelligence remained intact and no other brain circuits were lesioned.  The individual exhibited negligible remorse and minimal concern for the needs of other people.  These changes lasted at least eight years.

Nevertheless, the term acquired sociopathy is, arguably, applied loosely.  For example, this term is not used to differentiate sociopathy from psychopathy or antisocial personality disorder.  To illustrate, researchers have utilised this term to label individuals who have experienced neurological decline, such as dementia, together with behaviours that violate social norms or the rights of other people—including physical assault, theft, indecent exposure (e.g., Mendez et al., 2011)