Narcissism

Narcissism is a psychiatric term referring excessive self interest. It's been equated with terms such as egoism, vanity, self conceit, and selfishness. Developmentally it is considered a normal stage in early childhood. It is thought that a baby simply focuses on itself and it's self interest at the earliest developmental stages.  Narcissists as adults have also been called 'King Baby".  or "Queen Baby".  Developmentally the journey of a person is seen as moving from excessive self interest to health interest in others.  The golden rule is 'do unto others as you would have them do unto you'.   Also spiritually the second greatest command of the Bible after Love God was "Love your neighbour as yourself."  Abnormal love of self is narcissism named after the Greek boy who drowned from falling in love with his mirror image in the lake. Altruism the opposite of narcissism is considered a healthy coping strategy and evidence of psychological maturity.  In lay language, a narcissist is a 'taker' .
Narcissism is an excessive trait in sociopaths and psychopaths and anti social personality disorders.  It is common and transitory in mood disorders in general but more prominent in Bipolar Mood Disorders.  People who suffer from Mania act and appear very Narcissistic.
Drug addiction and alcoholism are commonly associated with narcissism.  Social skills are commonly lost in addiction and people only care about themselves and getting their drugs.
Empathy is a mature depth of relation which a person can have with another. Narcissists commonly lack the capacity for empathy. Empathy is different from sympathy which is more superficial and less connecting.
Narcissism in general is equated with emotional immaturity and spiritual immaturity.  However, narcissists can be very smart and clever though they would not be wise.