Kevin, as one British film critic writes, seems "alarmingly familiar" to some parents -- the teen who bullies other children and shows cruelty to animals, never showing a shred of empathy.
The fictional child in a new award-winning film, "We Need to Talk About Kevin," reveals his psychopathic colors early before going on a killing rampage at his high school.
The character's mother, played by Tilda Swinton, wonders if it was her fault, and it would be comforting to say, "no." But psychiatric experts say that psychopathy affects 3 to 6 percent of the population and is genetically based.
"It's biological and one of the most inherited human characteristics," said Dr. Igor Galynker, associate chair of psychiatry and director of the Family Center for Bipolar Disorder at Beth Israel Medical Center in New York City.
The horror film, directed by Lynne Ramsey and due in theaters Jan. 27, 2012, also stars Ezra Miller as Kevin and John C. Reilly as the teen's estranged father. It just took top awards at the London Film Festival.
"The event this movie describes is two normal parents and a psychopath child, but that is farther from reality," said Galynker.
The television character Dexter, a serial killer whose father is also psychopathic, is actually closer to the truth.
Both dramas send chills up the spines of anxious parents, who might wonder if their child is not just detached and antisocial, but indeed, a dangerous psychopath in the making.
"Callousness and unemotional behavior are the hallmark of the illness," said Galynker. "They have a feeling of grandiosity and makes them behave as if the rules do not apply. There is a certain glibness and they feel entitled. They cannot be punished -- like Teflon."
Psychopathy is a complex term that is used mostly by researchers to describe antisocial behavior that is impulsive, aggressive, deceitful and with a desire to break all the rules.
In the psychiatrists' bible, the Diagnostic Standards Manual (DSM), the mental disorder is classified as "conduct disorder" in those under 18 and "antisocial personality disorder" in adults.
"These people really see you as a piece of furniture and the empathy that allows us to feel others' feelings is missing," he said. "These people are wired differently. Their brains are different."
About 50 percent of these neurological traits are inherited and 50 percent are shaped by other influences. Having the genetic predisposition and growing up in an aggressive environment can be lethal.
"Intimidation and bullying creates bullies," said Galynker. "In a perfect environment, raised by well-meaning parents, you can still draw a psychopath."
A study published in the Archives of General Psychiatry, reported last year that increased gray matter was found in several areas of the brain in boys with psychopathic traits.
It's not always easy to identify, especially in children, who can be callous and cruel and torture their peers. And when psychopaths are diagnosed, they are hard to treat, though there has been some success with empathy training, according to Galynker, who said, "It takes years."
Bipolar disorder can also mimic psychopathy.
"When they are on the manic side, they can be callous," he said. "They have a Teflon factor and can be grandiose and break the rules and think they get away with it. But this would be treatable. A psychopath is permanent."
It is easy to diagnose a psychopath in hindsight, according to Darwin Dorr, a professor and director of clinical training at Wichita State University in Kansas.
"We must be careful because kids can act out for all kinds of reasons," he said. "You look at the history of an adult psychopath. Were they doing these things on the playground?
"We all do bad things, but with a true psychopath there is a predation about them," he said. "They prey on other people. That is part of their MO. Kids do bully, but is there a pattern of preying on kids?"
Normal Kids Are Social; Psychopaths Are Predators
From age 6 to 13, when children are developing their skills and value systems, they are busy with social activities such as sports or playing an instrument.
"These pre-psychopaths are not doing that," said Dorr. "They are prowling and trolling, looking for something to get into. They are not normal, busy kids. ... They are finding short cuts to success."
Researchers don't know why.
"We look at fine families and one comes out to be a psychopath," he said. "And the one raised in the slums comes out a good person and gives back to the world."
One of the most infamous youth psychopaths was Eric Harris, the teen who opened fire at Colorado's Columbine High School in 1999 with his depressive friend, Dylan Klebold, killing 13 and injuring 24. Both killed themselves afterwards.
Experts interviewed by ABCNews.com on the 10th anniversary of the Columbine shootings in 2009, said that can't predict which teens will go on a suicide-driven rampage.
"Not all psychotics or psychopaths are going to kill and most are not dangerous," said veteran FBI behavioral scientist Kenneth V. Lanning.
In 2000, the National Institute of Justice joined forces with the Secret Service and the Department of Education to assess ways to prevent school shootings. It looked at 37 incidents to find patterns in school-aged assassins, concluding that all are male and most are loners with some kind of grievance. More than half had revenge as a motive.
"But that's typical of almost every adolescent," said Lanning.
Harris was described as controlling, manipulative and sadistic, but very much in touch with reality.
"Psychopaths don't feel guilty because they are blind to guilt," said Frank Ochberg, a former FBI psychiatrist who led the counseling team after Columbine.
Often, they are well-liked and charming and can be "wheeler-dealers and manipulators," he said.
In fiction, they are self-focused characters like J.R. Ewing from television's "Dallas" and Scarlett O'Hara from "Gone With the Wind."
When raised in a nurturing family, they tend to be thrill-seekers -- race car drivers and mountain climbers.
"They see themselves as victims, not telling the truth, avoiding, changing the truth around," according to psychologist Dorr. "They have a deficiency of anxiety. We would be nervous if we messed up. They are so cool, they can do dangerous things. And when they are caught, they are very smooth and don't feel guilty, and talk themselves out of it."
He also warned that parenting styles that are too permissive or too authoritarian can encourage a budding psychopath, who needs structure, limits and not aggression.
"Authoritative parents who are warm and provide support seem to lead the best," said Dorr.
Sometimes, with early intervention, teens can be helped in cognitive therapy to help them get out of their narcissism or self-centeredness.
"But it's tricky to diagnose," he said, "especially for parents."