I feel like psychopaths would only be likely to be serial killers if they were VERY DEEPLY fucked up; they have a more direct instinct for pure self-preservation than normal humans. However I think they would be more likely to act out violently if directly threatened than normal humans, given the increased focus on self-preservation combined with lack of remorse and poor impulse control.

Normal people, on the other hand, are much more likely to experience acute feelings of persecution, separation from society, deep emotional hurt, etc, and act out against humanity as a result.