This article provides a description of five different concepts of the narcissistic personality disorder: the psychoanalytic concepts according to Kohut and Kernberg, the atheoretical concept of DSM-III(-R) and two so-called compromise concepts. The different concepts are compared and potential consequences investigated.

In order to obtain a systematic comparison of concepts, two (partly overlapping) meta-theoretical dimensions are applied: 1. focus (description of a stable outcome versus understanding of a dynamic developmental process) and 2. level of abstraction (concrete versus abstract).

Concepts directed towards the description of a stable outcome in concrete terms are more reliable than concepts with a high level of abstraction, and consequently more suitable for empirical research. Concepts with a higher level of abstraction attempt to provide insight into the dynamic developmental process of the disorder and the actual experiential world of the patient. They facilitate an empathic approach of the patient.

The authors advocate a multi-conceptual, multi-assessment approach using research strategies and assessment instruments that are closely related to the level of abstraction and the focus of the different concepts. This diagnostic approach might alleviate the often assumed contradiction between reliability on the one hand and validity and clinical usefulness on the other.