Narcissistic personality disorder (NPD) is one of many mental conditions that fall under another condition: dramatic personality disorder (DPD). Individuals would be considered narcissistic when their actions and words concentrate on their personal needs and/or yearnings. When the same individuals take self-aggrandize to another level, being exceedingly conscious of him/herself, then all the self-admiration should lead to being diagnosed with NPD. Not only their self-image becomes distorted, they have intense, unstable emotions.  In my opinion, those emotions lead destructive verbal outbursts hurting their relationships with others.
Mayo Clinic’s webpage on narcissistic personality disorder list possible symptoms that may be seen on individuals with NDP. They don’t care about other people’s feelings so they take advantage of others. They even don’t recognize others’ emotions and feelings. People with NPD expect constant admiration and praise. They would be easily hurt and rejected if, for example, they don’t get the expected commendations. Not only narcissistic individuals believe they’re special and consequently act like that, they believe they are better then others and believe that other people are jealous of them. Speaking of jealousy, narcissistics envy others. 
“Hurting their relationships” was mentioned in the first paragraph, therefore people diagnosed with narcissistic personality disorder have trouble keeping relationships. The same people have fragile self-esteem, yet they attempt to be seen as strong-willed or unsentimental. Sufferers of NPD expect others to go along with their ideas and plans. I think that symptom makes sense since they embellish their achievements or talents. Furthermore, they set unrealistic goals. 
Have you seen news stories on TV that displays person(s) imagining about delightfulness, power, and success? Well, that story may be centering on a narcissistic individual. The last symptom to inform others is horrible for me to witness. It is expressing scorn for those they feel are inferior.  Isn’t that sickening?
Mental health professionals (psychiatrists and psychotherapists) are trained to recognize if the individuals they are consulting display a mental disorder. People with narcissistic personality disorder will seek treatment when they are deeply affected. They won’t be content, in general, if their behavior hinder them to form healthy relationship with others. Most often they will seek help when they are stressed with dramatic life events. They want to know how to deal with the problems after not having success to make things better. A diagnosis will be made by a mental health professional by comparing symptoms he/she notices and the patient’s life experiences with the symptoms that comprise of a person with narcissistic personality disorder. Then, a determination will made to consider if the patients’ symptoms meet the standard requisite for a diagnosis of NPD. 
Causes of Narcissistic Personality Disorder
There aren’t any known causes of narcissistic personality disorder. There’s just numerous theories about the possible causes of it. Most health care professionals pledge to the biopsychosocial model of causation - meaning that biological, psychological, and social factors are the reasons behind the formation of NPD. That model views that there is no single reason is solely responsible. Instead, it follows the theory that the complex and likely intertwined nature of all three factors are equally pertinent. 
Lastly, research suggests that there is a small increased risk for NPD to be “passed down” to their children. 
Cure for Narcissistic Personality Disorder
It may obvious to some people that mental health professionals don’t attempt to cure people of their mental orders. They are only capable of providing resources to their patients with the objective of assisting them working with their personal and emotional issues. It is unlike an oncologist trying to find a medicinal cure for cancer, which can be eliminated from one’s body. 
There are various types of therapy available for people with narcissistic personality disorder. Severe cases of it will involve being hospitalized for a short period of time. If solo sessions with a psychotherapist doesn’t work well for a patient, then an alternative would be utilizing group therapy. The patient may be more likely to comply since the person will see the psychotherapist in a less authoritative role. The less severe cases will enable patients to only need outpatient mental health services. Those cases involve the client being able to have self-control and doesn’t display self-harming behaviors. 
Medications are not being developed to assist with the treatment of narcissistic personality disorder. What is needed for the patients is for them to learn new ways of perceiving things that let them be less stressed with their relationships with other people. Antidepressants may be prescribed to help the people diagnosed with NPD and are also anxious or depressed. 
There are anecdotal reports in the medical literature that the selective serotonin reuptake inhibitors (SSRI), which are frequently prescribed for depression, reinforce narcissistic grandiosity and lack of empathy with others.