Adaptation of the narcissistic personality inventory among a portuguese sample of incarcerated juvenile offenders

The aim of the present study was to assess the psychometric properties of the Narcissistic Personality Inventory (NPI) and two of its short forms (NPI-16 and NPI-13) among a Portuguese sample of male incarcerated juvenile offenders (N=221). Of these, only the NPI-13 short version demonstrated a good fit in terms of its factor structure. The NPI-13 also showed promising psychometric properties in terms of its internal consistency, convergent validity, discriminant validity, and criterion-related validity. Statistically significant associations were found with age of crime onset, crime seriousness, conduct disorder symptoms, alcohol abuse, and cannabis use. These findings justify the use of the NPI-13, especially its Entitlement/Exploitativeness dimension, among incarcerated male youths.
Portuguese Foundation for Science and Technology (FCT) [Grant SFRH/BPD/86666/2012] with co-financing of the European Social Fund (POPH/FSE), the Portuguese Ministry of Education and Science (MEC), the FEDER under the PT2020 Partnership Agreement (UID/PSI/01662/2013), and national funds provided by FCT- Foundation for Science and Technology [UID/SOC/04020/2013]