Psychopathy in adolescent offenders: an item response theory study of the antisocial process screening device-self report and the Psychopathy Checklist: Youth Version.

Few studies have examined the item functioning of youth psychopathy measures or compared the functioning of clinician and self-report based indices. Even fewer studies have made these comparisons in both male and female adolescent samples. The present study examined the applicability of items from two psychopathy measures, the Antisocial Process Screening Device (APSD; Frick, P. J., and Hare, R. D., 2001, The Antisocial Process Screening Device. Toronto, Ontario, Canada: Multi-Health Systems) and Psychopathy Checklist: Youth Version (PCL:YV; Forth, A. E., Kosson, D. S., and Hare, R. D., 2003, The Psychopathy Checklist: Youth Version. Toronto, Ontario, Canada: Multi-Health Systems), to adolescent boys and girls who had come into contact with the law. Item Response Theory was used to test item functioning of the two psychopathy indices. Examination of the Item Response Theory trace lines indicated that the APSD and the PCL:YV have both highly discriminating and poorly discriminating items and that the measures differ in the regions of psychopathy they cover. The PCL:YV is particularly effective at assessing interpersonal and affective features of psychopathy and to a lesser extent, lifestyle and antisocial features. The APSD appears to be effective at assessing narcissism and impulsivity but not callousness. In addition, the items most discriminating of the underlying construct of psychopathy for males and females demonstrate some important differences. These findings suggest that the measures may tap different underlying elements of the same overlaying construct. This may account for modest correlations between the measures. The findings suggest that clinicians should be aware of the regions that each measure best taps and also suggest that continued refinement and revisions to the youth psychopathy measures may be required