Personality disorders, psychopathy and other mental disorders: co-morbidity among patients at English and Scottish high-security hospitals

Mental health legislation in Britain has traditionally encouraged a distinction between personality disordered and mentally ill offenders, but research on co-morbidity indicates that few patients exhibit an Axis I or an Axis II disorder in isolation. This study compared male high-security hospital patients in the English Mental Health Act categories of psychopathic disorder (n = 54) and mental illness (n = 61) and the Scottish legal category of mental disorder (n = 60), using structured instruments to assess personality disorders, psychopathy and Axis I disorders. The mental illness and psychopathic disorder categories were not differentiated by personality disorders, psychopathy, or Axis I disorders, except for more lifetime drug abuse and more lifetime and current psychosis among the mentally ill. A majority of patients with mental disorder under Scottish legislation also exhibited personality disorders. Grouping by primary clinical diagnosis of personality disorder or mental illness produced few differences on Axis I or Axis II, and overall there was a relatively strong correlation between the presence of an Axis I and an Axis II disorder. Legal and clinical attempts to separate personality disordered and mentally ill offenders may be ill-conceived because Axis I and Axis II disorders tend to coexist.