But there is disagreement over whether these and other characteristics of antisocial personality disorder are a result of a person’s genetics or whether they develop as a result of a person’s environment in childhood. What is considered most likely is that in most cases, it is a combination of these factors. Functional magnetic resonance imaging brain scans of people with antisocial personality disorder have shown differences in their brains from what is typically seen in people without a personality disorder. (1,2,3) For example, researchers have seen abnormalities in the gray and white matter volumes in the parts of the brain related to attention, self-regulation, self-control, and resolving conflicts. (1,2) Brain scans have also revealed decreased connections among certain brain areas and abnormal organization of the brain’s network in the brains of individuals with antisocial personality disorder. (3) But to date, it is not known what leads to these differences. While individuals with antisocial personality disorder are often referred to as sociopaths in popular culture, the American Psychiatric Association does not use that term to describe them. People with antisocial personality disorder may also show arrogance and an inflated sense of self-confidence. They ignore the safety of others and may disregard safety for themselves as well. In addition to lying, a person with antisocial personality disorder may frequently steal and start fights. They may even derive pleasure from seeing other people experience harm or pain. They may have substance use problems as well. (4) Men are much more likely to be diagnosed with antisocial personality disorder than women, but the reasons for this are not understood. (4) Two studies estimated that approximately 4.5 or 6.8 percent of men have antisocial personality disorder, and both estimated that 0.8 percent of women have it. (5) European studies have found lower estimates, of approximately 1 to 1.3 percent in men and up to 0.2 percent in women. (5) Symptoms of antisocial personality disorder may decrease as a person ages, particularly around their forties. (4) But this decrease does not necessarily mean the condition goes away. It may simply look different in older adults, or people who have it may learn to hide their symptoms better from others as they grow older. They may also experience a decline in mental, emotional, or physical health because of the energy spent over their lifetime opposing social norms and potentially engaging in self-destructive behavior. (6) Antisocial personality disorder is much, much more commonly diagnosed among people in prison. Among the worldwide prison population, one study estimated that nearly half of men (47 percent) and 1 in 5 women (21 percent) have antisocial personality disorder. (5)

A history of child abuseA parent with a drug or alcohol use disorderA parent with antisocial personality disorder (4)Family conflictGenetic mutationsPoverty (7)Childhood neglect (8)Long periods of childhood spent in orphanages (8) or other forms of institutionalization (9)

A survey of people with antisocial personality disorder found that the condition is more commonly diagnosed among people who are male, Native American, younger, unmarried, or living in the western United States. People with lower incomes or an education no higher than high school were also at a higher risk. (10) A person with antisocial personality disorder may have shown the following behaviors before age 18:

Animal crueltyIntentionally setting fires (4)Drug or alcohol dependence or excessive useFrequently breaking the law or school rules for no obvious reasonCruel or aggressive behavior toward other peopleEngaging in bullying or fightingForcing others to engage in sexual activityStealingUsing weaponsSkipping school before age 13Lying for personal gainRunning away from homeVandalism and property destructionMood swingsBeing bullied by othersDifficulty making friends or maintaining close relationships (7)Poor performance in school (8)

Those people are more accurately described as asocial — that is, having such anxiety and lack of confidence in social situations that they avoid them and may even isolate themselves. According to the study mentioned earlier, 1 in 4 adults in the United States exhibits such antisocial behaviors, or about 20 percent, compared with the 4 percent prevalence of ASPD. (10)

The following are common or possible behaviors of people with antisocial personality disorder, but showing one or more of these behaviors does not mean a person definitely has the disorder:

Frequently lying or otherwise tricking or deceiving othersActing impulsivelyEngaging in risky behavior that may harm themselves or others, such as frequent speeding and reckless drivingFlattering others to gain somethingIntentionally inflicting physical or psychological harm on othersFrequently causing or getting into fightsRefusing to meet financial, family, or job responsibilitiesViolating rules in public or private establishments or other social normsBreaking the law, possibly to gain something they want or for the fun of itMaking a decision without considering whether it will harm othersCommitting physical or sexual assaultManipulating, gaslighting, or otherwise trying to control othersRegularly exaggerating stories, especially to make themselves look betterSeeking revenge for perceived wrongs against them, whether the insult is real or imaginedExcessively using alcohol, illegal drugs, or other substancesExpressing pleasure in another person’s sufferingRefusing to accept reasonable personal limitations