Clues Indicating A Demonic Presence In A Person

How can we tell if/when there is/are demon(s) in a client? Here are some clues, although in many cases other factors may be behind these clues instead:

(1) Who is in control? Does the person feel emotionally helpless to resist?
(2) “Something came over me”.
(3) “My father/mother was like this.” (Generational curse or spirit.)
(4) Hearing voices. “A voice told me ….” Common with spirits of suicide/death.