I think the changes made to the DSM-V for personality disorders make for a significant improvement over the previous diagnostic criteria. The previous definition focused too much on a list of externally observed behaviors, and the new changes shift that focus to something closer to the root disordered thought patterns that make up a PD.
General Criteria for a Personality Disorder (DSM-5)
The essential features of a personality disorder are impairments in personality (self and interpersonal) functioning and the presence of pathological personality traits. To diagnose a personality disorder, the following criteria must be met:
A. Significant impairments in self (identity or self-direction) and interpersonal (empathy or intimacy) functioning.
B. One or more pathological personality trait domains or trait facets.
C. The impairments in personality functioning and the individual's personality trait expression are relatively stable across time and consistent across situations.
D. The impairments in personality functioning and the individual's personality trait expression are not better understood as normative for the individual's developmental stage or socio-cultural environment.
E. The impairments in personality functioning and the individual's personality trait expression are not solely due to the direct physiological effects of a substance (e.g., a drug of abuse, medication) or a general medical condition (e.g., severe head trauma).
The two basic factors that all personality disorders share are 1) a reduced sense of self and 2) a disability in interpersonal functioning. These two factors together are defined as personality functioning impairments. The different named personality disorders each display these basic personality functioning impairments through one or more personality traits out of a given list of 25.
Impairments of Self (Identity and Self-direction) and impairments of Personal Functioning (Empathy and Intimacy) are rated on a scale of 0-4, with a level of 2 (moderate impairment) being diagnostically significant.
Self
Identity
0 Little or no im-pairment - Has ongoing awareness of a unique self; maintains role-appropriate boundaries-
1 Some impairment - Has relatively intact sense of self, with some decrease in clarity of boundaries when strong emotions and mental distress are experienced-
2 Moderate impairment - Depends excessively on others for identity definition, with compromised boundary delineation.-
3 Severe impairment - Has a weak sense of autonomy/agency; experience of a lack of identity, or emptiness. Boundary definition is poor or rigid: may show overidentification with others, overemphasis on independence from others, or vacillation between these.-
4 Extreme impairment - Experience of a unique self and sense of agency / autonomy are virtually absent, or are organized around perceived external persecution. Boundaries with others are confused or lacking.-
Self-direction
0 Little or no im-pairment - Sets and aspires to reasonable goals based on a realistic assessment of personal capacities-
1 Some impairment - Is excessively goal-directed, somewhat goal-inhibited, or conflicted about goals.-
2 Moderate impairment - Goals are more often a means of gaining external approval than self-generated, and thus may lack coherence and/or stability.-
3 Severe impairment - Has difficulty establishing and/or achieving personal goals.-
4 Extreme impairment - Has poor differentiation of thoughts from actions, so goal-setting ability is severely compromised, with unrealistic or incoherent goals.-
Interpersonal Functioning
Empathy
0 Little or no im-pairment - Is capable of accurately understanding others’ experiences and motivations in most situations-
1 Some impairment - Is somewhat compromised in ability to appreciate and understand others’ experiences; may tend to see others as having unreasonable expectations or a wish for control.-
2 Moderate impairment - Is hyperattuned to the experience of others, but only with respect to perceived relevance to self.-
3 Severe impairment - Ability to consider and understand the thoughts, feelings and behavior of other people is significantly limited; may discern very specific aspects of others’ experience, particularly vulnerabilities and suffering.-
4 Extreme impairment - Has pronounced inability to consider and understand others’ experience and motivation.-
Intimacy
0 Little or no impairment - Maintains multiple satisfying and enduring relationships in personal and community life-
1 Some impairment - Is able to establish enduring relationships in personal and community life, with some limitations on degree of depth and satisfaction.-
2 Moderate impairment - Is capable of forming and desires to form relationships in personal and community life, but connections may be largely superficial.-
3 Severe impairment - Has some desire to form relationships in community and personal life is present, but capacity for positive and enduring connections is significantly impaired.-
4 Extreme impairment - Desire for affiliation is limited because of profound disinterest or expectation of harm. Engagement with others is detached, disorganized or consistently negative.-
Here is also a quick list of the 25 different personality traits associated with personality disorders. They are grouped into the five basic categories of Negative Affectivity, Detachment, Antagonism, Disinhibition, and Psychoticism. (Obviously these are traits that anyone can have, but to be diagnostically relevant it is combined with the personality functioning impairments as described above.)
Negative Affectivity
1. Anxiousness
2. Emotional lability
3. Hostility
4. Perseveration
5. (Lack of) restricted affectivity
6. Separation insecurity
7. Submissiveness
Detachment
8. Anhedonia
9. Depressivity
10. Intimacy avoidance
11. Suspiciousness
12. Withdrawal
Antagonism
13. Attention seeking
14. Callousness
15. Deceitfulness
16. Grandiosity
17. Manipulativeness
Disinhibition
18. Distractibility
19. Impulsivity
20. Irresponsibility
21. (Lack of) rigid perfectionism
22. Risk taking
Psychoticism
23. Eccentricity
24. Perceptual dysregulation
25. Unusual beliefs and experiences
Finally, considering all these aspects of the Personality Disorder in general, the DSM-V defines Narcissistic personality disorder as such:
Narcissistic Personality Disorder (DSM-V)
The essential features of a personality disorder are impairments in personality (self and interpersonal) functioning and the presence of pathological personality traits. To diagnose narcissistic personality disorder, the following criteria must be met:
A. Significant impairments in personality functioning manifest by:
1. Impairments in self functioning (a or b):
a. Identity: Excessive reference to others for self-definition and self-esteem regulation; exaggerated self-appraisal may be inflated or deflated, or vacillate between extremes; emotional regulation mirrors fluctuations in self-esteem.
b. Self-direction: Goal-setting is based on gaining approval from others; personal standards are unreasonably high in order to see oneself as exceptional, or too low based on a sense of entitlement; often unaware of own motivations.
AND
2. Impairments in interpersonal functioning (a or b):
a. Empathy: Impaired ability to recognize or identify with the feelings and needs of others; excessively attuned to reactions of others, but only if perceived as relevant to self; over- or underestimate of own effect on others.
b. Intimacy: Relationships largely superficial and exist to serve self-esteem regulation; mutuality constrained by little genuine interest in others‟ experiences and predominance of a need for personal gain
B. Pathological personality traits in the following domain:
1. Antagonism, characterized by:
a. Grandiosity: Feelings of entitlement, either overt or covert;
self-centeredness; firmly holding to the belief that one is better than others; condescending toward others.
b. Attention seeking: Excessive attempts to attract and be the focus of the attention of others; admiration seeking.
C. The impairments in personality functioning and the individual's personality trait expression are relatively stable across time and consistent across situations.
D. The impairments in personality functioning and the individual's personality trait expression are not better understood as normative for the individual's developmental stage or socio-cultural environment.
E. The impairments in personality functioning and the individual's personality trait expression are not solely due to the direct physiological effects of a substance (e.g., a drug of abuse, medication) or a general medical condition (e.g., severe head trauma).
The wording has changed significantly, but the essence of the Narcissistic Personality Disorder definition remains the same.