I agree with you that these terms need to be defined.
It never fails that in opinion threads like these, it doesn't take long before it becomes evident that every person has their own working definitions,
which don't appear to provide a cohesive basis for the discussion.
But judging by the name of this thread,
I would think there has already been a poll on the most emotionally un-stable type,
and it doesn't appear to be that scientific.