Narcissistic Personality Disorder - Prevalence and Comorbidity

What is the Difference between Healthy Narcissism and the Pathological Kind?
In my book "Malignant Self Love - Narcissism Revisited", I define pathological narcissism as:
"(A) life-long pattern of traits and behaviors which signify infatuation and obsession with one's self to the exclusion of all others and the egotistic and ruthless pursuit of one's gratification, dominance and ambition."
Luckily for us, we are all narcissists to some degree. But healthy narcissism is adaptive, flexible, empathic, causes elation and joy (happiness), and help us to function. Pathological narcissism is maladaptive, rigid, persisting, and causes significant distress, and functional impairment.
Prevalence and Age and Gender Features
According to the DSM IV-TR, Narcissistic Personality Disorder (NPD) is diagnosed in between 2% and 16% of the population in clinical settings (between 0.5-1% of the general population). The DSM-IV-TR proceeds to tell us that most narcissists (50-75% of all patients) are men.
We must carefully distinguish between the narcissistic traits of adolescents - narcissism is an integral part of their healthy personal development - and the full-fledge disorder. Adolescence is about self-definition, differentiation, separation from one's parents, and individuation. These inevitably involve narcissistic assertiveness which is not to be conflated or confused with Narcissistic Personality Disorder (NPD).
"The lifetime prevalence rate of NPD is approximately 0.5-1 percent; however, the estimated prevalence in clinical settings is approximately 2-16 percent. Almost 75 percent of individuals diagnosed with NPD are male (APA, DSM IV-TR 2000)."
From the Abstract of Psychotherapeutic Assessment and Treatment of Narcissistic Personality Disorder By Robert C. Schwartz,Ph.D., DAPA and Shannon D. Smith, Ph.D., DAPA (American Psychotherapy Association, Article #3004 Annals July/August 2002)
However, as the narcissist grows old and suffers the inevitable attendant physical, mental, and occupational restrictions, Narcissistic Personality Disorder (NPD) is exacerbated.
Studies have not demonstrated any ethnic, social, cultural, economic, genetic, or professional predilection or susceptibility to the Narcissistic Personality Disorder (NPD).
Still, Robert Milman suggested a condition that he labeled "Acquired Situational Narcissism". He observed a transient and reactive form of the Narcissistic Personality Disorder (NPD) in certain situations, such as under constant public scrutiny and exposure.
Comorbidity and Differential Diagnoses
Narcissistic Personality Disorder (NPD) is often diagnosed with other mental health disorders ("co-morbidity"), such as mood disorders, eating disorders, and substance-related disorders. Patients with Narcissistic Personality Disorder (NPD) are frequently abusive and prone to impulsive and reckless behaviours ("dual diagnosis").
The comorbidity of Narcissistic Personality Disorder (NPD) with other personality disorders, such as the Histrionic, Borderline, Paranoid, and Antisocial Personality Disorders, is high.
Narcissistic Personality Disorder (NPD) is often misdiagnosed as Bipolar Disorder (the manic phase), Asperger's Disorder, or Generalized Anxiety Disorder - and vice versa.
Though the personal styles of patients with Cluster B personality disorders resemble each other, they also substantially differ. The narcissist is grandiose, the histrionic coquettish, the antisocial (psychopath) callous, and the borderline needy.
From my book, "Malignant Self Love - Narcissism Revisited":
"As opposed to patients with the Borderline Personality Disorder, the self-image of the narcissist is stable, he or she are less impulsive and less self-defeating or self-destructive and less concerned with abandonment issues (not as clinging).
Contrary to the histrionic patient, the narcissist is achievements-orientated and proud of his or her possessions and accomplishments. Narcissists also rarely display their emotions as histrionics do and they hold the sensitivities and needs of others in contempt.
According to the DSM-IV-TR, both narcissists and psychopaths are "tough-minded, glib, superficial, exploitative, and unempathic". But narcissists are less impulsive, less aggressive, and less deceitful. Psychopaths rarely seek narcissistic supply. As opposed to psychopaths, few narcissists are criminals.
Patients suffering from the range of obsessive-compulsive disorders are committed to perfection and believe that only they are capable of attaining it. But, as opposed to narcissists, they are self-critical and far more aware of their own deficiencies, flaws, and shortcomings."
Bibliography
Goldman, Howard H., Review of General Psychiatry, fourth edition, 1995. Prentice-Hall International, London.
Gelder, Michael, Gath, Dennis, Mayou, Richard, Cowen, Philip (eds.), Oxford Textbook of Psychiatry, third edition, 1996, reprinted 2000. Oxford University Press, Oxford.
Vaknin, Sam, Malignant Self Love - Narcissism Revisited, seventh revised impression, 1999-2006. Narcissus Publications, Prague and Skopje.