I sent out a tweet the other day about a study showing that men who score high on a narcissism test appear to experience more stress than those who score low (but not narcissistic women). Stress was measured by "cortisol levels," a hormone that "signals the level of activation of the body’s key stress response system, the hypothalamic-pituitary-adrenal (HPA) axis."
You can see a report about study here. I thought the most interesting part was the link to the 40 item Narcissistic Personality Quiz, which is based on the measure in this paper: Raskin, R. & Terry, H. (1988). A Principal-Components Analysis of the Narcissistic Personality Inventory and Further Evidence of Its Construct Validity. Journal of Personality and Social Psychology, 54(5). Note that Journal of Personality and Social Psychology is one of the best and most rigorous psychology journals, so the source is excellent.
Try taking the quiz. I just did and scored an "8,' which suggests a low level of narcissism. I confess, however, that I am wondering if my low score was a reflection of my lack of narcissism or of my knowledge of the narcissism literature in concert with a bit of self-delusion. I also confess that I completed it a second time as if I were one especially narcissistic boss that I once worked with. That boss (in my opinion) earns a 32 -- a very high score as above 20 indicates narcissism. The quiz omits one thing this person did which indicates narcissism: It was amazing how, no matter what the topic, how within 3 minutes, every conversation with that boss always became conversation about what a successful and impressive person he was and all the people who admired him and his work.
If you really are the mood for self-assessment, you can take both this quiz and the (less scientific) Asshole Rating Self-Exam or ARSE. That way you can find out if you are a narcissist, a certified asshole, or both!