Narcissism is a personality trait theorized to be a self-confidence mechanism that defends against stress, anxiety, and depression, especially the kinds that are most likely to be suffered by people with Dependent and Avoidant personality disorders. This self-confidence is obtained by telling ourselves to ignore the factual consequences of our actions. Because stress, anxiety, and depression bring productivity down, small amounts of narcissism help in maintaining confidence and leading a healthy lifestyle. Conversely, too much narcissism causes people to procrastinate, become lazy, refuse to admit they made a mistake, become incapable of putting themselves in other people's shoes, turn into a Know-Nothing Know-It-All, or become a victim of Pride. Such traits characterize all those with narcissistic personality disorder whom are commonly referred to as narcissists.
In public, narcissists actively seek to project an image of perfection which inspires admiration, envy, and/or worship from others. However, despite appearing boastful and overconfident to those around them, narcissists are in reality highly insecure and depend on narcissistic supply in order to maintain peace of mind. By obtaining external confirmation for their fantasies of superiority, the narcissist is able to cancel out deep-rooted fears of being ignored or otherwise failing to receive recognition commensurate to their inflated self-worth. By the same token, narcissists are highly sensitive to criticism or failure in any form which they consider dangerous to their image in others' eyes. Due to the fact that narcissists automatically view anyone who undermines their grandiose self-image with paranoia and hatred, he/she will often target such individuals with extreme prejudice and go to ANY lengths to neutralize them as a "threat". However, unlike sociopaths, narcissists are not entirely devoid of redeeming qualities given that they are capable of experiencing shame for their actions as well as sincere (albeit self-centered) affection towards others.
Narcissists generally disdain emotional intimacy due to the fact that they largely view others as either enemies or inferiors who exist for their own gain or gratification. In the event that a narcissist genuinely becomes emotionally attached to someone, he/she views that person as a mere extension of themselves as opposed to a separate individual with his/her own thoughts and feelings. Given that they see those they profess to care about as merely part of a greater whole, narcissists have no qualms deceiving or manipulating such individuals whenever it suits them to do so. Furthermore, in the case of particularly amoral and/or unstable examples of this trope, the friends and loved ones of a narcissist remain always at risk of being killed if they fail to meet his/her expectations or their deaths will somehow further his/her own selfish agenda.
More recently, psychologists has begun to discuss that there actually are two subtypes of narcissistic personality disorder. An "overt" or "grandiose" subtype, which is expressed by behavior that most people would typically associate with narcissism; grandiosity, arrogance, emotional coldness, aggressiveness, and exhibitionism. The other is the "covert" or "vulnerable" subtype, which are more emotionally sensitive, and tend to be much quicker to feel anxious, depressed, and victimized when they feel deprived of attention and/or respect. Where the "grandiose" type is much better at maintaining a strong surface as they tend not to care very much about what other people think of them and are much less susceptible to experience shame, the "vulnerable" type is conversely preoccupied with fears of rejection and abandonment and the whole reason for their behavior appears to be an attempt to (over-)compensate for low self-esteem and a deep-seated sense of shame. At the core, the "vulnerable" type is believed to exhibit narcissistic behavior to cope with a trauma or similar emotional baggage, while for the "grandiose" type it is never about compensating for anything; they're simply acting out their expectations.
There is some controversy as to what type of childhood narcissists had. Some researches believe that narcissists were overvalued by their parents, while others think that they had a rather dismal childhood. With the recent introduction of the idea of grandiose and vulnerable subtypes, the consensus seems to be that grandiose narcissists were likely the former, while vulnerable narcissists likely had the latter.
Some forms of narcissism employ black and white thinking called splitting as a central defense mechanism to stabilize their sense of selfviewing themselves as wholly good and those that would criticize or humiliate them as purely wicked or contemptible.