To be clinically diagnosed with Narcissistic Personality Disorder (NPD), certain personality traits must be present.

The below content is from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, 1994, commonly referred to as DSM-IV, of the American Psychiatric Association. European countries use the diagnostic criteria of the World Health Organization.

A pervasive pattern of grandiosity (in fantasy or behavior), need for admiration, and lack of empathy. [jma: NPD first appeared in DSM-III in 1980; before that time there had been no formal diagnostic description.] Additionally, there is considerable overlap between personality disorders and clinicians tend to diagnose mixes of two or more.

Grandiosity is a special case, but lack of empathy and exploitative interpersonal relations are not unique to NPD, nor is the need to be seen as special or unique. The differential diagnosis of NPD is made on the absence of specific gross behaviors.

Borderline Personality Disorder (BPD) has several conspicuous similarities to NPD, but BPD is characterized by self-injury and threatened or attempted suicide, whereas narcissists are rarely self-harming in this way. BPD may include psychotic breaks, and these are uncharacteristic of NPD but not unknown. The need for constant attention is also found in Histrionic Personality Disorder, but HPD and BPD are both strongly oriented towards relationships, whereas NPD is characterized by aloofness and avoidance of intimacy.
Grandiosity is unique to NPD among personality disorders, but it is found in other psychiatric illnesses. Psychopaths display pathological narcissism, including grandiosity, but psychopathy is differentiated from NPD by psychopaths’ willingness to use physical violence to get what they want, whereas narcissists rarely commit crimes; the narcissists I’ve known personally are, in fact, averse to physical contact with others, though they will occasionally strike out in an impulse of rage. It has been found that court-ordered psychotherapy for psychopaths actually increases their recidivism rate; apparently treatment teaches psychopaths new ways to exploit other people. Bipolar illness also contains strong elements of grandiosity. See more on grandiosity and empathy and its lack below.

SIMPLE TERMS
Narcissistic Personality Disorder (NPD) is a pattern of self-centered and egotistical behavior that is destructive to others. We all have (or should have) some self-love which is not the same thing. Just because we like to take selfies does not mean we hurt people. This egotistical behavior goes much further – they put their own needs before others and they tend to not only step on people that get in their way but actually go out of their way to crush/ruin/hurt them. At this time, there is no cure for NPD and most people affected by this are not self-aware enough to get help. They have no interest in changing and therefore they rarely seek counseling.

The disorder begins by early adulthood and per the DSM-IV, the person must be indicated by at least five of the following characteristics:

1. An exaggerated sense of self-importance (e.g., exaggerates achievements and talents, expects to be recognized as superior without commensurate achievements)
2. Preoccupation with fantasies (e.g., unlimited success, power, brilliance, beauty, or ideal love)
3. Believes he/she is “special” and can only be understood by, or should associate with, other special or high-status people (or institutions)
4. Requires excessive admiration
5. Has a sense of entitlement
6. Selfishly takes advantage of others to achieve their own ends
7. Lacks empathy
8. Is often envious of others or believes that others are envious of them
9. Shows arrogant, haughty, patronizing, or contemptuous behaviors or attitudes

What are some warning signs? Next Read “Common Traits of a Narcissist”