In his influential book The Mask of Sanity, Hervey Cleckley presented a series of vignettes which distilled typical features of large numbers of individuals with psychopathy whom he had interviewed (Cleckley, 1941). He described them as charming, callous and superficial, commenting that their lack of conscience or genuine emotion was camouflaged by the ‘mask’ of a healthy, functional individual. People with psychopathy commit a large amount and wide variety of violent and non-violent crimes, and are resistant to attempts at rehabilitation (Reid & Gacono, 2000). The definition of psychopathy has changed little since Cleckley's time, and the aetiology of the condition remains unknown.

Psychopathy shares general features with personality disorders listed in DSM-IV-TR (American Psychiatric Association, 2000), even though it is not included among them. Personality disorders comprise a group of disorders that usually result in impaired interpersonal functioning. Individuals exhibit enduring patterns of cognition, emotion and behaviour that deviate markedly from cultural expectations. The three clusters of personality disorders listed in DSM-IV-TR (American Psychiatric Association, 2000) fall under the headings ‘odd–eccentric’ (cluster A), ‘emotional–dramatic’ (cluster B) and ‘anxious–fearful’ (cluster C), and each contains further subtypes.

Reclassification of psychopathy

Psychopathy as a distinct psychiatric condition disappeared from diagnostic classifications with the publication of DSM-III (American Psychiatric Association, 1980). In DSM-IV-TR, psychopathy is called antisocial personality disorder and in ICD-10 (World Health Organization, 2004) it is dissocial personality disorder. However, although both antisocial and dissocial personality disorders include several traits reflecting psychopathic personality (for example, lack of guilt/remorse, impulsivity), it is possible to meet the diagnostic criteria for these disorders solely on the basis of the behavioural manifestations of antisocial behaviour (for example, violation of social norms, irresponsibility, criminality).