I think that one lost out during the bitter wrangling over the classification of personality disorders in the DSM-V (and man, it appears to have been more tense than a combined faculty meeting, Democratic caucus and a dinner party to which ex-spouses were both invited). But I just noticed this from the Wikipedia entry:
DSM-5
The formulation of narcissistic personality disorder in the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) was criticised for failing to describe the range and complexity of the disorder. Critics said it focuses overly on “the narcissistic individual’s external, symptomatic, or social interpersonal patterns—at the expense of … internal complexity and individual suffering,” which they argued reduced its clinical utility.[26]
The Personality and Personality Disorders Work Group originally proposed the elimination of NPD as a distinct disorder in DSM-5 as part of a major revamping of the diagnostic criteria for personality disorders,[27][28] replacing a categorical with a dimensional approach based on the severity of dysfunctional personality trait domains. Some clinicians objected to this, characterizing the new diagnostic system as an “unwieldy conglomeration of disparate models that cannot happily coexist” and may have limited usefulness in clinical practice.[29] The general move towards a dimensional (personality trait-based) view of the Personality Disorders has been maintained despite the reintroduction of NPD.
Don’t know if they knew Trump was running or whether we just got lucky, but imagine trying to get people to grasp how ill he was if we were trying to explain him in terms of a “dimensional approach based on the severity of personality trait domains.”