人格分裂 ~= split personality 雙重人格 ~= multiple personalities I'm not a psychologist, so I can't really tell you the clinical difference between the two terms. I'm just giving the translation. After reading a few articles, it seems that there is very little clinical difference between a split personality disorder and a multiple personality disorder. They are both referred to as "dissociative disorders", the new fancy term for these things. 疑神疑鬼 ~= extremely suspicious

人格分裂：Dissociative Disoders；多重人格：Multiple-personality Disorders；