Building on what you've posted, psychopaths having diminished capacity to build relationships could very well lead to depression or atleast unhappiness. I find this really interesting because we often see a psychopath represented as a remorseless beast void of any human emotions yet, looking from this perspective, it almost paints psychopathy as a dibilating disorder.

I also note it probably wouldn't be correct for me to use psychopathy as the name of a disorder but it should be fine for casual discussion.