 I am the author of Malignant Self-Love, Narcissism Revisited. What is the difference between healthy narcissism and the pathological kind? In my book Malignant Self-Love, I define pathological narcissism as a lifelong 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, it is flexible and bathic, and it causes elation and joy, happiness. It helps us to function and cope. Healthy narcissism by comparison is maladaptive, it is rigid, persisting, and it causes significant distress and functional impairment in a variety of contexts such as family life or the workplace. According to the Diagnostic and Statistical Manual, and a variety of other publications such as the Abstract of Psychotherapeutic Assessment and Treatment of Narcissistic Personality Disorder, well according to these publications, Narcissistic Personality Disorder is diagnosed in between 2 and 16% of our population in clinical settings, or between 0.5% and 1% of the general population. So about 1% of the general population are narcissists. The Diagnostic and Statistical Manual proceeds to tell us that most narcissists, at a minimum of 50% but usually 75%, are men. We must carefully distinguish between the narcissistic traits of adolescents and those of others. Narcissism is an integral part of the healthy personal development of adolescents. Adolescence and pubescence is about self-definition, differentiation, separation for one's parents, and individuation. These processes inevitably involve narcissistic assertiveness, which is not to be conflated or confused with narcissistic personality disorder. That's the reason that NPD or Narcissistic Personality Disorder cannot be safely diagnosed before early adulthood. As the narcissist grows old and suffers the inevitable attendant physical, mental and occupational restrictions, narcissistic personality disorder is actually exacerbated. Studies have not demonstrated any ethnic, social, cultural, economic, genetic or professional predilection or susceptibility to narcissistic personality disorder, although narcissists tend to cluster, concentrate and migrate to certain specific professions where public exposure is high and narcissistic supply is guaranteed. Robert Milman, for instance, suggested a condition that he labeled acquired situational narcissism. He observed that there is a transient and reactive form of narcissistic personality disorder in certain situations, such as under constant public scrutiny and exposure. Narcissistic personality disorder is often diagnosed with other mental health disorders and this is known as comorbidity. So it's very common to find narcissistic personality disorder diagnosed in the same patient with mood disorders, eating disorders and substance related disorders. Patients with narcissistic personality disorder are frequently abusive and prone to impulsive and reckless behaviors and this is known as dual diagnosis. The comorbidity of narcissistic personality disorder with other personality disorders such as the histrionic, the borderline, the paranoid and most definitely the antisocial personality disorder, psychopathy, this comorbidity is pretty high. Narcissistic personality disorder is often misdiagnosed as bipolar disorder in the manic phase or as Asperger's disorder or as generalized anxiety disorder and vice versa. Though the personal styles of patients with cluster B personality disorders, these styles resemble each other, they also substantially differ. The narcissist is grandiose, his trionic is coquettish, the antisocial, the psychopath is callous and the borderline is needy and clinking. In my book Malignance of Love, I wrote, as opposed to patients with a borderline personality disorder, the self-image of the narcissist is stable, he or she are less impulsive and less self-defeating and self-destructive and less concerned with abandonment issues, they are not as clinging as borderlines. In contrary to the histrionic patient, the narcissist is achievements oriented and proud of his or her possessions and accomplishments. Narcissists also rarely display their emotions as histrionics do, and they hold their sensitivities and own in needs of others in utter contempt. According to the DSM, both narcissists and psychopaths are tough-minded, glib, superficial, exploitative and unemphatic, but narcissists are less impulsive, less aggressive and less deceitful. Psychopaths rarely seek narcissistic supply as opposed to narcissists. And 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, shortcomings and limitations. So narcissistic personality disorder has few things in common with a variety of other mental health disorders, but it should be differentiated from them. And this we call differential diagnosis.