Validation of self-report measures of narcissism against a diagnostic interview.

The Pathological Narcissism Inventory (PNI) and the Narcissistic Personality Inventory (NPI) are often used to screen for pathological narcissism but have rarely been validated against a clinician-administered diagnostic interview. Our study evaluated the convergent validity of the PNI and NPI against a diagnostic interview for narcissistic personality disorder (NPD) in a clinical population. We used data from a psychiatric outpatient center located in Switzerland (n = 123). Correlations between PNI/NPI and NPD ranged between .299 and .498 (common variance 9.0-24.8%). The PNI and NPI should be used carefully to screen for NPD. We highlight a need to increase the compatibility between the conceptual underpinnings of the PNI, NPI and NPD.