Background: The Narcissism Inventory (NI) is a frequently used German
inventory for measuring narcissism in clinical settings; an additional short
version (NI-90) also exists. Psychometric properties of the NI-90 scales were
examined in clinical and non-clinical adolescent samples. Methods: Two
adolescent samples were assessed with the NI-90: a non-clinical sample (n =
439, mean age ± SD = 15.05 ± 1.77 years) and a clinical sample (n = 235, 18.26
± 0.77 years). Confirmatory factor analysis and principle component analysis
were used to scrutinize the structure of the scales. Multiple regression
analysis was used to predict the scores on two scales (helpless self; negative
body self). Results: This study revealed heterogeneity in the NI-90 scales,
which in turn explains the wide range seen in Cronbach’s α (from 0.53 to
0.93). The postulated 4-factor structure could not be replicated in both
samples. Multiple regression analysis revealed that personality disorder did
not significantly predict negative body self or helpless self scores, whereas
eating, mood, as well as somatoform and conversion disorders did. One NI-90
scale (greedy for praise and reassurance) showed sufficient psychometric
quality for the measurement of narcissism in both samples. Conclusion: Based
on the results, the authors recommend revising the NI-90. Items that may be
useful for measuring aspects related to affective and body image complaints
are presented. The greedy for praise and reassurance scale may be valuable for
measuring features of ‘overt’ narcissism
