What types of people engage in sadism? Serial killers and psychopaths, for starters, Stone reported. Of the some 100 serial killers he has studied, he said, more than 90 percent were psychopaths. And psychopaths in turn, he explained, are extremely narcissistic, impulsive, sensation seeking, and deceitful. They also lack goals, compassion, and remorse, and sponge off others. In Stone’s opinion, the most depraved people who commit homicide are psychopathic murderers who enjoy torturing their victims.