Narcissistic personality disorder

Narcissistic personality disorder (NPD) is a personality condition. Such people show exaggerated feelings of self-importance. They find it difficult to show empathy and love to other people. They want to be admired by others and need to gain power and success. 
The American Psychiatric Association’s "Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition" ("DSM-5") categorises NPD as Cluster B personality disorder, with antisocial personality disorder, borderline personality disorder and histrionic personality disorder. 
Cluster B personality disorders are also known as “dramatic” personality disorders. Common to these is very emotional behaviour which creates problems in relationships. Studies have found that up to 6.3% of the general population suffers from narcissistic personality disorder and it is more prevalent in men than it is in women.
History.
Before the introduction of narcissistic personality disorder, the term narcissism was used to explain a person's extreme self-love and self-admiration. The word "narcissism" comes from Greek mythology. A handsome young man named Narcissus saw his own reflection in a pool of water and fell in love with himself. Narcissus' love could not be returned back and therefore he became a flower, which was named after him. 
In 1925 Robert Waelder introduced the term "narcissistic personality" and by 1968 the term narcissistic personality disorder was used by Heinz Kohut.
Signs and traits.
In order to be diagnosed with Narcissistic Personality Disorder, The American Psychiatric Association’s DSM-5 says that a person must show at least five of the following problematic behaviors:
It is important to note that there is a difference between narcissistic personality disorder and narcissistic traits. People with narcissistic personality traits show some of the behaviour discussed above, but to a lesser degree than those with full-blown NPD.
Psychopathology.
People with NPD feel very confident in their self and in what they are able to do and achieve and think that they are the best in everything. They need to be admired by people around them and are obsessed with fantasies of power, beauty and talent. They consider themselves unique and special and believe that they should be treated differently. They find it difficult to care for and show empathy to others and therefore struggle to keep stable relationships and show love or interest in anyone else. An obvious symptom of NPD is arrogant and impatient behaviour and attitude. These traits make it difficult for people suffering from narcissistic personality disorder to ask for clinical help as they often do not understand they need to do so.
According to the DSM-5 narcissistic characteristics are often seen in successful people, but an individual can be diagnosed with NPD only when these traits affect their every day life by making it harder.
People with NPD often also have additional psychological disorders such as depression, bipolar disorder and substance abuse, as well as other disorders from the second cluster of personality disorders. 
Types of NPD.
Narcissistic personality disorder can take many forms. These are the three general categories and their descriptions:
-       "Grandiose narcissists": likely to take advantage of others and ignore their well-being and emotions
-       "Shy narcissists": tend to feel both better and worse than people around them, narcissistic traits act as a defence strategy when they don’t feel “enough”.
-       "High-functioning narcissists": are competitive and look for attention, they are flirty and energetic 
Causes.
Narcissistic Personality Disorder is the result of a mix of genetic and environmental factors. Studies have suggested that there is 45-80% heritability, meaning that these traits are passed on from a parent to a child, supporting the genetic cause of the disorder. However it is important to remember that what is inherited is not the disorder per se, but a genetic predisposition (genotype) to developing this or any other type of mental disorder. This is where nurture comes in, because it is the environment that the person is living in that activates (or does not activate) the genotype. 
A lot depends on the dynamics within the family. If a child with a predisposition to narcissistic personality disorder is doted upon or praised excessively, they will internalise the belief that they are better than others, while at the same time fearing that they are not - this is a recipe for narcissism. On the other hand, if the child is neglected or constantly criticized, they may also develop narcissistic personality disorder as a way of compensating for the lack of love and attention. In both cases the child has suffered damage to their psyche that is called a narcissistic injury. 
Finally, from a neurological view, studies have found that NPD is connected to a "problem" in the brain, making it hard to express and control emotions such as empathy. 
Treatment.
There is no strong evidence of treatment or managing options that work. However, as with many personality disorders, the most common and used option is psychotherapy and psychodynamic methods.These options seem to be the ones most likely to control narcissism. Mental conditions that often come with narcissistic personality disorder, such as depression or anxiety disorder can be treated, but there is no evidence that medicine can treat narcissistic symptoms.