As has been done with autism spectrum disorders, it’s becoming increasingly common to think of NPD as falling on a spectrum of narcissism, ranging from normal or healthy narcissism (which most of us have to some degree) all the way to psychopathy/sociopathy (variations of Antisocial Personality Disorder or ASPD) at the top. What we call malignant narcissism is actually NPD shading into ASPD.
Narcissism is a normal trait that helps us survive, but it becomes pathological when there is too much of it. On the narcissism spectrum, just below NPD and above healthy narcissism is a disorder called The Destructive Narcissistic Pattern, or DNP. It’s not included in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), but Dr. Nina Brown has written books about the disorder, which I haven’t read yet (I never even heard of DNP until a few days ago), but here is a description of DNP:
The destructive narcissistic pattern (DNP) is a term used to describe a constellation of characteristics generally associated with pathological narcissism, but which are fewer and less severe. Nonetheless, these characteristics negatively impact relationships. The destructive narcisist’s typical interaction produces negative reactions in others. For example, the individual devalues others, lacks empathy, has a sense of entitlement, and is emotionally shallow. He may function very well and be successful economically, but is unable to form and maintain stable relationships, as evidenced by numerous partners or marriages. The DNP, Brown asserts, is often unrecognized. Although others may find him frustrating and difficult, the individual with DNP can be charming when charm is perceived to be to his benefit.
Dr. Brown’s book “The Destructive Narcissistic Pattern” can be purchased on Amazon.
The blogger CZBZ has also written about DNP on her blog, “The Narcissistic Continuum” and has devised a detailed graph that shows the placement of disorders on the narcissistic spectrum: http://n-continuum.blogspot.com/2013/11/narcissism-key-from-healthy-to.html
DNP is probably much more common than full-blown NPD. These people can be very difficult to deal with but because their symptoms are less severe they would be more likely to respond to (and seek) therapy and may not be completely without empathy and have a stunted or limited conscience instead of an absent one.
The only problem I have with this continuum is that almost everyone would be on the narcissism spectrum, since most people (except for those whose self esteem has been all but obliterated) have some degree of healthy narcissism.