I don't know that I believe in demonic possession, but I would never dabble with "tools" that invite spirits...such as the Ouija Board, or chants, spells, etc. The mind is just too fragile as it is! I've watched a lot of films about possession. One interesting one, based on the book by the same name, is The Rite. It is the supposedly true story of a priest who went to the Vatican to study the rituals of excorcism. The book is more down-to-earth, while the film takes a lot of dramatic liberties to appeal to moviegoers. In the end, it seems to validate the concept of demonic possession.

Now...as for meds. When I attempted to wean myself off antidepressants, over a period of two years, finally going off completely...thinking I'd be okay...I was not! No, I didn't feel possessed at all; I was just incredibly sad, crying all the time and pretty much a basket case. So, if you have meds that help you, I say, be mindful of that and use them for your well-being!
Patty