In 1957, a local sheriff in Plainfield, Wis. entered a farmhouse to investigate the disappearance of the mother of one of his deputies. Bernice Worden, the owner of a local hardware store was missing, and now the sheriff was at the home of quiet farm boy Ed Gein, who was seen at Worden’s shop just before her disappearance.

The sheriff found Worden’s corpse in the kitchen of Gein’s residence. Police entered the house and found a sordid scene: mangled pieces of human flesh were stored in boxes, and human skin had been used to upholster furniture and was fashioned into clothing.

The son of an alcoholic father and fanatically religious mother, Gein grew up a few miles from Plainfield. Convicted of at least two murders, Gein is believed to have raided the local cemetery for years prior to his capture, earning the nickname “The Mad Butcher of Plainfield.” Gein was confined to the Mendota Health Institute until his death from cancer in 1984, but he has since become the basis for countless motion pictures and campfire stories.

Many people refer to serial killers as psychotic, but there is a clear semantic difference between psychotics and psychopaths. Psychotics are delusional and can be medicated, but psychopaths are generally perfectly sane people who feel no empathy for others. Most serial killers are psychopaths, especially those who avoid capture by thinking rationally.

Kenneth D. Garlock, L.C.S.W., retired from psychiatric social work at the Patent State Hospital in California. During his 20-year tenure, Garlock worked with individuals such as Charles Manson who had committed criminal acts, but who were not necessarily delusional.

“Many serial killers are sociopaths, or psychopaths, which means that they are perfectly rational, but that they have no capacity for empathy,” Garlock said.

What is remarkable about psychopaths is their incapacity to form deep relationships, along with their extremely self-centered perspective.

“These people can be perfectly sane, charming, and bright, but they show a complete disregard for other people,” Garlock said.

It is unclear whether psychopaths have a genetic predisposition to their pathology, or whether it is the result of growing up in a disruptive background.

“It can be genetic, but each person’s psychosis is based on his or her own fantasy life,” Garlock said

Many movies have featured psychopaths as the main character. Gein became the basis for horror-movie masterpieces such as “Psycho,” “Silence of the Lambs,” and “Texas Chain Saw Massacre,” which created a fictional family to carry out the gory deeds of one real-life character.

Audiences have always been fascinated by the incomprehensible psychology of psychopaths. On-line auctions offer items from Gein’s farm, his car was on display at a state fair in the 1950s, and in 2000 vandals stole his tombstone.

“It’s fascinating because it’s so bizarre to most of us,” Garlock said. “It’s incredible to think that some of these charming people could commit such horrendous acts and not care. Most people won’t go so far as to buy souvenirs of psychopaths, but they are unquestionably intriguing.”

It is hard to know or predict at exactly what point a psychopath becomes a danger to society. The movie characterizations of a psychopath are often far more sensational than in reality.

“Most psychopaths are not dangerous, although you can never be sure,” Garlock said. “I’m convinced some of our leading industrialists, or even Hollywood stars, have psychopathic tendencies. Some of them are so power-driven that they just don’t care about people. They’re going to do what they have to do to get what they want. They won’t literally destroy another person, but they might figuratively stab someone in the back.”

One of the reasons that it’s so hard to diagnose psychopaths is that, because of their self-centered frame of mind, they don’t think there is anything wrong and behave for the most part as sane and rational members of society.

Garlock said the only way to reach a psychopath is the same way one would hope to reach anyone else: by remaining polite and calm.

“I never lied, yelled, or screamed at my clients, and they responded to that. They may be psychopaths, but they are people, and all people respond to respect,” Garlock said.