Charles Manson may be dead, but the shock and horror over his crimes and those of his followers remains. Questions also linger about what could possibly motivate someone to behave with such cold-blooded malice, and how he could show "no signs of rehabilitation" after so much time had passed. 

. Manson, who died Nov. 19th at age 83, was the convicted mastermind of several brutal murders in the late 1960s, perhaps most famously of the pregnant actress Sharon Tate, who was stabbed to death while she begged for her baby's life, and whose blood was used to write the word “pig” on the front door of her home. Manson and his followers are believed to have carried out perhaps 35 murders, allegedly in hopes of sparking a race war.

Read: Are You a Sociopath?

What kind of person could orchestrate these murders? Many cult leaders are narcissists — people with humongous egos who constantly crave admiration while showing no empathy toward others. They have a profoundly inflated sense of self-importance and entitlement. Jim Jones, the American head of the Jonestown cult that became infamous when hundreds of members simultaneously drank Kool-Aid laced with cyanide and died, had this personality disorder. Those deaths included children and people who drank the poison under duress, and were horrifying much like the Manson murders. But Manson’s pathology seems to go deeper than narcissism.

He showed signs throughout his life of antisocial personality disorder, a condition in the diagnostic manual of psychiatry that is marked by a lack of regard for the feelings of other people, and for what is right and wrong. “People with antisocial personality disorder tend to antagonize, manipulate or treat others harshly or with callous indifference,” the Mayo Clinic explains. “They show no guilt or remorse for their behavior.” They are arrogant, known to lie and can often seem charming, which is how they manipulate people, and will often take part in aggressive, impulsive, irresponsible or risky behavior.

Psychopathy and sociopathy are extreme forms of antisocial personality disorder: “The more egregious, harmful, or dangerous behavior patterns are referred to as sociopathic or psychopathic,” Psychology Today explains. The terms are often used interchangeably, and these two types of people certainly have a lot in common — they engage in crazy behavior for the thrill, usually have criminal records, are generally impervious to treatment and, because they mimic normal behavior and deceive the people in their lives, no one around them may suspect they are deranged.

Read: How to Spot a Psychopath

But the two categories are not the same, with the main difference being their backgrounds: psychopathic traits are more innate, while sociopaths blossom under certain social and environmental conditions, such as an abusive upbringing. Psychology Today also notes that “unlike their sociopathic counterparts, psychopathic criminals are cool, calm, and meticulous” — when they commit crimes, they plan every detail and are often much more difficult to catch. The serial killer Jeffrey Dahmer, for example, was found to have dismembered and eaten his victims, and confessed to killing 17 people from 1978 through 1991.

2sharon-tate Actress Sharon Tate was perhaps Charles Manson's most famous victim, murdered by his followers while 8.5 months pregnant. Credit: Getty Images

5coroner-tate Coroner's office personnel wheel the body of film actress Sharon Tate from her home in Bel Air, California, on Aug. 9 after she was found murdered. Credit: Getty Images

Live Science estimates that about a quarter of the male federal prison population is comprised of psychopaths, so was Manson just another inmate in that group, or was he a sociopath? There’s evidence to argue either way.

According to biographer Jeff Guinn, who also wrote the book “Manson: The Life and Times of Charles Manson,” the murderer showed violent tendencies even as a young boy. “Beginning in first grade, Charlie would recruit gullible classmates, mostly girls, to attack other students that he didn’t like,” Guinn wrote for Biography. “Afterward, he’d swear to teachers that his kid followers were just doing what they wanted — he couldn’t be held responsible for their actions. Because no one thought a 6-year-old could be capable of such Machiavellian manipulation, Charlie usually got off scot-free while his disciples were punished.” His first cousin Jo Ann also recounted a story in which 7-year-old Manson, living with her family and “fascinated by guns and, especially, knives or any other sharp implements,” threatened her with a sickle he had found.

Read: Inside The Criminal Mind

Some would say Manson was a product of a troubled childhood, as he had claimed his mother Kathleen was a teenage prostitute, but Guinn says that was a lie, although she did spend some time in prison during his youth — when he went to live with his cousin.

4police-bus Charles Manson sits on a police bus in Los Angeles after being charged with murder. Credit: Getty Images

Antisocial personality disorders do show themselves at young ages, the Mayo Clinic says, with signs like aggression toward people and animals, theft, deceitfulness and destruction of property. Those behaviors may dissipate over time, but it might not be what is appears: “It's not clear whether this decrease is a result of aging or an increased awareness of the consequences of antisocial behavior.” Antisocial personality disorder is a lifelong condition.

Read: 10 Personality Traits Of Psychopaths

Apart from the aggression Guinn noted, a young Manson showed the other early signs of the disorder, with a record of theft and other crimes and a history of deceitfulness. He was in and out of prison and Biography says that while behind bars he was considered dangerous “before he discovered the benefits of being a ‘model prisoner.’” Probation reports called him unpredictable — volatility is a symptom of psychopathy and sociopathy — and “constantly striving for status and securing some kind of love.”

7manson-mug In this 2009 handout photo from the California Department of Corrections and Rehabilitation, Charles Manson, 74, poses at Corcoran State Prison while serving a life sentence for conspiring to murder seven people during the 'Manson family' killings in 1969. The picture was taken as a regular update of the prison's files. Credit: Getty Images

As a man, he abused drugs, which is common among people with antisocial personality disorder, and experienced delusions about an impending armageddon. He appeared all over the spectrum: Psychopaths are meticulous, and he allegedly criticized his followers for being sloppy after some of their murders; meanwhile sociopaths are said to treat their inner circle well, something Manson by some accounts did with his followers.

Manson obviously had an extreme antisocial personality disorder, but was he born that way or did he grow into the notorious murderer whose crimes still send shivers up our spines all these years later? Until we understand these two conditions better, it’s not easy to know.

See also:

Psychopaths And Narcissists: What's The Difference?

Psychopaths and Domestic Violence