To their victims they seemed pretty normal at first, even admirable. Reinaldo Silvestre, a charming Miami con man with no medical training, is alleged to have operated on his plastic-surgery patients by shoving implants into their chests with a spatula; several were permanently mutilated. A drifter named Luis Garavito confessed in October to kidnapping, torturing and killing 140 children over five years in Colombia. Dylan Klebold went to the prom before shooting up Columbine High in April. Predators with such little regard for morality and human life defy rational explanation, right? Wrong, say an increasingly vocal group of psychiatrists and criminologists. Many of the most depraved, coldhearted criminals, they suggest, suffer from a definable but little studied psychiatric disorder known as antisocial personality. “We blame crime on everything from bad parenting to violent video games,” says University of Iowa psychiatrist Donald Black, whose book Bad Boys, Bad Men: Confronting Antisocial Personality Disorder was published early this year. “But medical journals don’t cover ASP, and no one wants to look at it. It’s baffling.” Not to be confused with occasional periods of bad behavior or crimes of passion, ASP is defined in the latest Diagnostic and Statistical Manual as a lifelong “pervasive pattern” of rule breaking and violating the rights of others that begins before age 15. ASPs are chronic troublemakers whose symptoms vary greatly in severity: they can be constant money borrowers, black sheep, pathological liars, white-collar criminals or, at the most severe end of the continuum, murderous felons. They are impulsive and grandiose, don’t learn from punishment, are poor self-observers, blame others for their problems and see themselves as victims. Their primary hallmark is a striking inability to feel empathy or guilt. According to a national study of psychiatric disorders, an estimated 7 million people in the U.S. have antisocial personality disorder, eight times as many men as women. The shocking videotapes that Harris and Klebold made before the Columbine massacre provide a unique glimpse into the antisocial mind, say those who have studied ASP. “What’s frightening is how cold and calculated all this was, with no regard for the consequences,” says Black. “They view it through their perverse world view, not seeing it as others would, which is a characteristic of antisocials.” Though the two boys expressed remorse for the hurt they were about to cause their parents, their ability to shut off such pangs of guilt is also characteristic of ASP. “There was some remorseful thinking, but not enough to compensate for the enormous excitement of the enterprise they were contemplating,” says Stanton Samenow, a psychologist and author of several books on criminal personality. Sociopathy has been recognized as a social menace since the mid-1800s , and antisocial personality disorder has been listed in the DSM since 1968. Yet surprisingly little research has been done on it. According to the National Institute of Mental Health, only $3 million was spent last year for research on ASP, and $31 million was spent on its childhood predecessor, conduct disorder. Yet $132 million was devoted to schizophrenia.