This quote is from a well thought out post by Tanos on Entitlement, posted in his weblog and linked from the ownership wiki on The Slave Register
I lived with someone with Narcissistic Personality Disorder. Looking back on it he had a somewhat D/s relationship with his lover, who had obvious Borderline traits. However there was no sense of mastery in his actions, attitudes, etc., merely entitlement without responsibility. Looking at my own behaviour I do, of course, act entitled, while at the same time discouraging such acting in my slaves. But I have a sense of responsibility and a dedication to them and their lives that is simply lacking from the purview of someone with NPD. I will and do take risks, including the risk of simply being an overt Master in a country where human ownership, consensual or not, is simply illegal. And that is a minor one given all the things in our lives.
A couple in our local scene are an obvious NPD/BPD couple, and the two tend to go together. While he seems to take reasonable care of his charge I feel a sense of creeping unease in their presence. Although emmie and mitda (and I myself) have all been diagnosed with Bipolar Disorder 1 it doesn’t seem to have any direct bearing on our M/s relationship. Obviously my moods and theirs impact the day to day functioning of that relationship but I can’t say I see an overall tendency that runs from BP symptomology to M/s dealings.