“The paper clarifies the nature of the disorder and allows others to explore the links between the clusters of symptoms and basic psychological and biological process more effectively.”

Psychopathic personality disorder is an old and controversial diagnosis. It is an important disorder in both health and also in criminal-justice settings where its presence can prolong an individual’s incarceration and it may be taken into account in death sentence adjudications. Our research sought to clarify the nature and structure of the symptoms used to define the disorder. The first step in establishing the validity of a diagnostic entity is to demonstrate that the symptoms of the disorder cluster together in a meaningful way. Our research applied new mathematical and statistical techniques—item response theory and confirmatory factor analysis—to tackle the problem. We showed that three clusters of symptoms underpinned the disorder. Interpersonally, those suffering from psychopathy are deceptive, glib and superficially charming. Affectively, they lack normal emotional experiences, while behaviorally, they are impulsive and irresponsible. Our analytic methods showed that this structure of symptoms held across several different methods of assessing the disorder. Critically, these analyses revealed that criminal and antisocial behavior are not defining features of the disorder but are essentially epiphenomena.

David J. Cooke
Professor of Forensic Clinical Psychology
Douglas Inch Centre and Glasgow Caledonian University
Glasgow, Scotland