Examination of the screening properties of the personality diagnostic questionnaire 4+(PDQ-4+) in a prison population

There is a high prevalence of personality disorder in most prison populatio ns. Many pass through the system undiagnosed. A screening instrument would improve identification. This study examined the screening properties of the Personality Diagnostic Questionnaire-4+ (PDQ-4+) in prisoners convicted of violent and sexual offences. A sample of British prisoners completed the s elf-report PDQ-4+ and were interviewed using the Structured Clinical Interv iew for DSM-IV Axis II disorders. When used to generate a total score, the PDQ-4+ had an acceptable overall accuracy as measured by the area under the Receiver Operating Characteristics (ROC) curve. The PDQ-4+ appears to have the properties suit able for use as a screening instrument, particularly w hen screening for the presence or absence of personality disorder rather th an for individual personality disorder categories. A graph is presented fro m which choices of cut-off score for different combinations of sensitivity and specificity can be made. A cut off total score of 25 or above yielded n ear optimal sensitivity and specificity. The suggested cut off score for th is population is lower than that previously suggested.