Antisocial personality disorder is on a continuum with psychopathy.

BACKGROUND Antisocial personality disorder (ASPD) and psychopathy are different diagnostic constructs. It is unclear whether they are separate clinical syndromes or whether psychopathy is a severe form of ASPD. METHODS A representative sample of 496 prisoners in England and Wales was interviewed in the second phase of a survey carried out in 1997 using the Schedules for Clinical Assessment in Neuropsychiatry, the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis II personality disorders, and the Psychopathy Checklist-Revised. RESULTS Among those 18 years and older (n = 470), 211 (44.9%) received a diagnosis of ASPD, of whom 67 (31.8%) were classified as psychopaths, indicated by Psychopathy Checklist-Revised scores of 25 and above. Symptoms of ASPD and psychopathy both demonstrated low diagnostic contrast when comparing subgroups of ASPD above and below the cutoff for psychopathy. There were no differences in demography, Axis I comorbidity, and treatment-seeking behavior. Psychopathic individuals with ASPD demonstrated comorbid schizoid and narcissistic personality disorder, more severe conduct disorder and adult antisocial symptoms, and more violent convictions. CONCLUSIONS Psychopathy and ASPD are not separate diagnostic entities, but psychopathic ASPD is a more severe form than ASPD alone with greater risk of violence. Dimensional scores of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition personality disorders (other than ASPD) may be helpful in identifying this specific subgroup.