It's my hypothesis that Narcissist Personality Disorder, NPD, is a progressive mental illness. It has it's roots in almost everyone to varying degrees, it begins as Everyday Narcissism, EN, and depending on how badly distorted your belief systems are, they either dissipate into the background as we age and mature or they can take center stage in your life as we slip further into mental illness, NPD, that is treatable and slowly into insanity, Malignant Narcissism, MN, which is not treatable..
EN > NPD > MN
Nearly all of us suffer from EN and don't even know it. Depending how prevalent it's been in infiltrating and overpowering our belief systems. How big a problem EN has become is reflected in the life we create. If you are filled with anxiety, anger, depression, irritability and discontentment and you find yourself having problems forming normal fulfilling relationships compounded with an addictive personality. You might want to take a look at your belief systems.
To see what your belief systems are, start taking your character defects and walk them back. Asking why do I believe this? Why do I believe this? The best way (my opinion) to find your character defects, is by finding a 12 step program and complete Step 6. Once you've listed them, you can humbly ask your higher power to remove them.