Psychometric Properties of the Italian Version of the Narcissistic Personality Inventory.

Abstract

The construct of narcissism, though still controversial, has considerable implications not only for clinical psychology (Kernberg, 1992; Kohut, 1971), but also for social psychology and individual differences (Baumeister, 1999). The lack of measurement tools for narcissism applicable by researchers from different theoretical backgrounds and working in different contexts is one of the factors that has slowed down the research into this particular aspect of the personality.
The Narcissistic Personality Inventory (NPI; Raskin e Hall, 1979; Raskin e Terry, 1988) is a self-administered tool, constructed to assess narcissism in a dimensional perspective also in the non clinical population. Although the scale does not measure Narcissistic Personality Disorder, the conceptualization of narcissism that underlies it is based on behavioral criteria for the narcissistic personality included in the DSM-III (American Psychiatric Association, 1980). This makes it a potentially interesting tool, given that it uses criteria applicable also in the clinical domain assessed in dimensional modalities that also make it potentially suited for use in the social field and that of individual differences. Moreover it is based on an explicitly a-theoretical definition of narcissism (American Psychiatric Association, 1980) – or perhaps it would be better to say trans-theoretical – which represents a “common language” both in clinical activity and in research. This makes the NPI a tool that can be used by researchers of different theoretical orientations, allowing the comparison of results and the exchange of scientific information.
The construct underlying the NPI considers narcissism a personological style characterized by grandiosity, fantasies of success, beauty and unlimited power, sense of entitlement, high sensitivity to criticism and manipulation in interpersonal relations (these characteristics have been retained almost unchanged in the two later editions of the DSM). 
The development of theories on narcissism and the availability of easy-to-use measurements like the NPI have favored the growth of research into narcissism, with an increase in the number of articles indexed in PsychInfo from 405 in the decade 1969-1978, to 1791 in the decade 1989-1998 (Soyer, Rovenpor, Kopelman, Mullins & Watson, 2001). A recent study showed that there are 146 studies indexed in PsychInfo in the period 1979-2003 that use the NPI as the measurement of narcissism (Del Rosario & White, 2005). Based on this data, it can be stated that the NPI is a widely used tool accepted as a dimensional measurement of narcissism in the non clinical domain. So far the evidence of the validity of the NPI as a clinical measurement of narcissism is limited to one single work (Prifitera & Ryan, 1984).