Psychopathy, or psychopathic personality, is a personality construct characterized by impaired empathy and remorse, persistent antisocial behavior, along with bold, disinhibited, and egocentric traits. These traits are often masked by superficial charm and immunity to stress, which create an outward appearance of apparent normality.
Hervey M. Cleckley, an American psychiatrist, influenced the initial diagnostic criteria for antisocial personality reaction/disturbance in the Diagnostic and Statistical Manual of Mental Disorders (DSM), as did American psychologist George E. Partridge. The DSM and International Classification of Diseases (ICD) subsequently introduced the diagnoses of antisocial personality disorder (ASPD) and dissocial personality disorder (DPD) respectively, stating that these diagnoses have been referred to (or include what is referred to) as psychopathy or sociopathy. The creation of ASPD and DPD was driven by the fact that many of the classic traits of psychopathy were impossible to measure objectively. Canadian psychologist Robert D. Hare later re-popularized the construct of psychopathy in criminology with his Psychopathy Checklist.