Obtaining an accurate history can be somewhat challenging for persons with narcissistic personality disorder, given the variability of the presentation. In the outpatient setting, individuals can be well related and high functioning while in the inpatient setting can be some of the most aggressive and challenging patients. A majority of the time, NPD patients come into contact with clinicians during emergencies were more often than not, they are noted to behave aggressively.[15]

The aggression indicates the severity of the personality disorder i.e., the more aggression detected, the personality disorder is considered more severe. Otto Kernberg cited extensive cases correlating aggression with the severity of personality disorders.[16]

Per the DSM, NPD includes:

A pervasive pattern of grandiosity (fantasy or behavior), need for admiration, and with lack of empathy, beginning by early adulthood, as indicated by at least five of the following:

• Has a grandiose sense of self-importance (e.g., exaggerates achievements, expects to be recognized as superior without actually completing the achievements)
• Is preoccupied with fantasies of success, power, brilliance, beauty, or perfect love.
• Believes that they are "special" and can only be understood by or should associate with, other special people (or institutions).
• Requires excessive admiration.
• Has a sense of entitlement, such as an unreasonable expectation of favorable treatment or compliance with his or her expectations).
• Is exploitative and takes advantage of others to achieve their own ends.
• Lacks empathy and is unwilling to identify with the needs of others.
• Is often envious of others or believes that others are envious of them.
• Shows arrogant, haughty behaviors and attitudes

The diagnosis of NPD as other personality disorder requires evaluation of long-term patterns of functioning. One needs to be cautious not to jump into hasty conclusions because NPD can trigger countertransference. A careful evaluation of the different aspects of a person's life, in addition to an understanding of the person's childhood development, can assist in the evaluation and diagnosis of NPD.

A standard psychiatric interview is often used to make a diagnosis of personality disorders. Otto Kernberg's structured clinical interview, which was created in 1981, has continued to undergo revisions and restructuring as a structured clinical interview for personality disorders. The current version is a semi-structured diagnostic interview that has questions focused on personality organization, defenses, object relations, and coping skills. This interview focuses on interpersonal relationships. The current version is copyrighted by the Personality Institute at The Weill Cornell Institute. The interview is based on psychodynamic principles and is expected to be used by persons who had have had previous training in psychoanalytical work.[17]

Other instruments may measure the severity of narcissistic personality disorder, such as the five-factor narcissism inventory that looks at the five aspects of general personality. There are about 148 questions that are asked on the measure.[18] Another measure that may be used is the Narcissistic Personality Inventory.[19]

The instruments above are mostly used in research settings. In the clinical world, the clinical interview is of most value. The focus of an excellent clinical interview continues to be on interpersonal relationships as persons with an NPD often present with conflicts with others be in inpatient or outpatient settings. In outpatient settings, often referrals are made at the behest of a loved one, and in inpatient or emergency room settings, symptoms often come into play when there is interaction with other personnel, especially others in authority. Persons with NPD often describe themselves in relation to others with themes of comparison.[10]

Often a clinician's countertransference may help with forming a diagnosis. Often, persons with NPD create feelings of either feeling flattered or admired or on the other extreme feelings of inadequacy and low self-worth.[20][21] Glen Gabbard is another analyst who has done extensive work in understanding these feelings described as "countertransference" in the therapist. As a clinician, it is always important to pay attention to feelings evoked in self by a patient as this is often diagnostic.

No standardized pharmacological or psychological treatment has been established for persons with narcissistic personality disorder.[10] More often than not, NPD is present, along with other mood disorders. Once a diagnosis is established, it is essential to discuss the diagnosis because of several challenges that mostly will be present in the future. It is equally important to treat ongoing symptoms of co-occurring affective disorders.[22]

Kohut and Kernberg have focused on long term therapy and exploring the relationship between a therapist and patient, which continues to be established treatment for persons with a narcissistic personality disorder.[23] Psychodynamic psychotherapy focuses on defenses present during therapy sessions.[24] Many therapists have advocated for ongoing therapy for patients with an established diagnosis of NPD. NPD may significantly reduce emergency department visits and lower the incidence of self-harm. Of note, studies are more focused on borderline personality disorder; however, borderline personality disorder's findings may be generalizable to other disorders as well.

Transference focused therapy is structured twice a week psychoanalytic therapy that focuses on personal expression of emotions toward a therapist. Given that persons with NPD can often be provoked by their perception of being treated by another, their own emotions towards other people are essential.[25]

Schema focused therapy is relatively new and focuses on alternate forms of cognitive-behavioral therapy, including activating emotional senses.[26]

There are no FDA approved medications for the treatment of NPD, but many patients may benefit from treatment of symptoms, including anxiety, depression, mood lability, transient psychosis, and impulse control issues. Antidepressants, including selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors, have been used. Risperidone, an antipsychotic, has shown benefit in some patients. Some patients are given mood stabilizers like lamotrigine.

The differential diagnosis often includes prevailing mood or anxiety disorders. Often persons with grandiose narcissism can present with heightened mood and more energy when excited by a new idea, which may initially point to a hypomanic/manic presentation; however, the personality aspect would be prominent in their interaction with others. On the other extreme, persons with vulnerable narcissism may present with salient features of dysthymia, depression, and anhedonia. However, the grandiosity and need for admiration would be prominent despite the affective symptoms, which would differentiate it from a major depressive disorder.The closest differentials continue to remain other cluster B personality disorders, including antisocial personality disorder, histrionic personality disorder, and borderline personality disorder. Persons with NPD, however, do not show overt signs of impulsivity and self-destructiveness associated with borderline personality disorder. Similarly, apparent emotional responses are associated with histrionic personality disorder. NPD is most similar to antisocial personality disorder with a lack of empathy and superficial charm. Persons with an antisocial personality disorder, however, would show a lack of morals compared to persons with NPD and have a past diagnosis of conduct disorder.

• Antisocial personality disorder
• Borderline personality disorder
• Histrionic personality disorder
• Major depressive disorder
• Obsessive-compulsive disorder
• Substance-induced mood disorder

The prognosis, as discussed above, depends on the presence of comorbid disorders and the level of functioning of the patient. Aggression is often directly related to the severity of the disease; rather, the more aggressive the patient appears, the more severe is the personality disorders.

The complications essentially involve the presence of comorbid conditions, including mood and substance use disorders. The presence of other personality disorders is also common. However, narcissistic personality disorder is associated with a higher risk of death by suicide compared to other personality disorders.[27] In contrast, there is mixed evidence of suicide attempts and persons with narcissistic personality disorder given that NPD is associated with factors such as “self-love” and “grandiosity” and comparatively less impulsivity.[28] Substance use disorder is also related to NPD, and when there is an association of substance use disorder with NPD, there is significantly more hostility and aggression that is also seen. This makes treatment even more challenging than usual. There are several theories related to both biology and trauma regarding the same.[29][30]

As detailed above, it is necessary to discuss the diagnosis with the patient as soon as possible. It is equally important to discuss the process of arriving at this conclusion, including clinical information gathered and observed behaviors. Discussion of other comorbid disorders, including mood and substance use disorders, if present, needs to be addressed. Often family members also require education about personality disorders, their behaviors, and complications.

1. Obtaining a detailed history is vital. A primary psychiatric interview focuses on symptoms; however, longitudinal assessments focusing on interpersonal relations are helpful to point toward a diagnosis of NPD.
2. Given that there are two subtypes established, it is essential to focus on being able to identify both grandiose and vulnerable forms, given that the latter is missed in place of other diagnoses.
3. It is essential to be mindful of other comorbid diagnoses given the high levels of comorbidity with affective and other cluster B personality disorders.
4. Literature has shown that most persons with narcissistic personality disorder are difficult to engage hence being aware of the same and being empathetic are necessary when beginning treatment
5. Once a diagnosis is established, it is important to share the same with the patient. Lack of sharing may lead to further complications during care
6. It is equally important to treat comorbid mood and substance use disorders.
7. It is crucial for treating clinicians to be aware that there are high rates of drop-outs and increased rates of therapeutic disruption with persons with a narcissistic personality disorder
8. It is essential to recognize that most clinicians experience negative countertransference when treating persons with NPD. Clinicians are advised to be aware of the same and process emotions that arise in treatment.

Often collaborative work is required in the medical setting when patients with NPD work with non-mental health professionals such as surgeons, medical nursing, nutritionists, etc. These patients are often described as "difficult and demanding," and importantly, their medical needs remain untreated. Often mental health professionals may be consulted for a mood disorder on the inpatient floor for a patient with underlying NPD and have to liaison with the primary medical team in charge of the patient. Other medical professionals must be educated about personality disorder and their countertransference towards the patient so that it does not impact clinical care. Mental health professionals in the consult-liaison service may provide support and education to the first medical teams as well.In the outpatient setting, patients are asked to discuss their diagnosis as they feel relevant to their medical providers. A partnership among medical professionals and other ancillaries may ensure optimal care. The education of both patients and their providers is also helpful.