Narcissism and depression are believed to sometimes occur together, probably because the narcissistic personality is incapable of developing true feelings of self-worth or intimacy with others. Some experts believe that narcissism can easily occur simultaneously with bipolar disorder, a type of depression. People with narcissism generally rely heavily on the care and attention of others for their feelings of self-worth, such that when that attention is withdrawn, they might fall into depression.
The causes of narcissism are believed to stem from neglect or abuse in infancy or very early childhood, so narcissism and depression might occur together due to the irreparable damage these early experiences might have had on the narcissist person's self-esteem. Some believe that the narcissist's extreme sense of self-involvement makes it difficult for him, not only to experience empathy with another's needs, but to fully perceive the existence of other individuals at all.
The typical narcissist believes that his own opinions and beliefs are always the correct ones, and that he is generally perfect in just about every way. Most psychologists believe, however, that the narcissist's extremely high self-opinion is just a facade covering deeply-held feelings of low self-esteem and low self-worth. It is therefore generally believed that the narcissist seeks to surround himself with people who will praise and flatter him, agree with all of his opinions and beliefs, and attend to all of his needs, even to the exclusion of their own. The average narcissist, however, is usually incapable of realizing that other people have valid feelings, needs, opinions, and beliefs of their own, which can make the narcissist a very difficult person for others to be around, especially in an emotionally intimate fashion.
Most psychologists believe that it is only a matter of time before the narcissist's friends, relations, and romantic partners assert their own needs. In order to do so, these individuals must typically reject the narcissist's delusions of personal greatness. Without the constant, unrelenting validation and support of those close to him, the narcissist is usually left without the inner resources to prop up his own sense of self-esteem and well-being. Narcissism and depression therefore might occur together because the narcissist may often find himself alone, without the strong social support he typically needs to continue feeling superior to others.
The typical narcissist cannot comprehend that he is not in some way superior to those around him. Symptoms of narcissistic personality disorder are believed to grow worse as the narcissist ages. The younger narcissist typically respects only those he sees as authority figures, such as parents or mentors, and only these are believed capable of keeping his often contrary personality in check. Psychologists believe that, as the typical narcissist reaches middle age and older, these authority figures usually die off, leaving the narcissist able to think as highly of himself as he likes and treat others as badly as he likes. As the aging narcissist grows harder and harder to deal with, he may find himself more and more socially isolated, such that narcissism and depression may be more likely to occur together as the individual reaches old age.