Validity and stability of the youth psychopathic traits inventory in a nonforensic sample of young adults.

We assessed the validity and stability of the Swedish developed Youth Psychopathic Traits Inventory (YPI; Andershed, Kerr, Stattin, & Levander, 2002) in Canadian nonforensic young adults. In Study 1, a total of 217 undergraduates completed the YPI as well as the Psychopathic Personality Inventory-Revised (PPI-R; Lilienfeld & Widows, 2005) and the Levenson Self-Report Psychopathy Scale (LSRP; Levenson, Kiehl, & Fitzpatrick, 1995). These measures were completed twice, with a mean of 28 days between administrations. Total YPI was strongly correlated with the PPI-R but also with the LSRP subscales. YPI higher order dimensions were meaningfully correlated with PPI-R dimensions of similar content. The YPI yielded fairly high temporal stability and was similar to the PPI-R and LSRP Primary Psychopathy scale. Using 111 undergraduates, in Study 2, we found the YPI was positively associated with antisocial attitudes and impulsivity and negatively associated with agreeableness and conscientiousness. This research extends the validity of the YPI beyond adolescents to Canadian young adults from nonforensic settings. Given its promise as a measure of psychopathic traits in adolescents and young adults, the YPI may prove useful in longitudinal research across these developmental periods.