Narcissism is excessive love of oneself. The word is based on the Greek myth of Narcissus, who resisted the advances of a nymph and was consequently made to fall in love with his own reflection. In psychology, extreme narcissism is a symptom of Narcissistic personality disorder, in which a person overestimates his own abilities and attractiveness, at the expense of concern for the needs and feelings of others. However, it has been argued that a moderate amount of narcissism is healthy.
The subject of narcissism has been an extremely popular topic in psychology research. Many instruments have been created to measure the trait, the most popular of which are the Minnesota Multiphasic Personality Inventory and the Narcissistic Personality Inventory. Factor analysis have revealed one overarching factor with many subtraits depending on resolution.