This kind of research is really fascinating to me, but I also wonder about the ethical aspects. If it's done purely for research purposes, I see little harm. 

If we're talking about possible applications of analysis like this, could it happen that certain people get automatically 'targeted' just because they exhibit certain psychopathic tendencies through their speech patterns.
 
I'm talking about the future of course, I don't want to delve into the realm of conspiracy... Perhaps I've been reading too many dystopian novels lately.