Yes...it is a common trait of disorders, and my understanding more related to NPD traits, than any other. NPD's and disorders are based on being very self centred or selffish. It is common with those that suffer from low self esteem, as well. It would be common in some HPD's types, due to thier attention seeking, "centre of attention" and self centreness. Thus the need to dominate conversations.
Again, self centredness is a common theme/symptom among many with disorders.
It is my understanding from what I read anyway and have even witnessed here on the forum. I believe I read it in a few spots and on the shrink4men site.
My ex, though didn't display the conversation part of the self centredness, but was self centered/selffish, never the less. I assume it has to do with the person's underlying personality, and how extreme they do it. Not all are the same, but understand,this is common.
Just my opinion.