Demonic possession? or mental illness?

Fascinating look at the real life story of Anneliese Michel that inspired two movies: The Exorcism of Emily Rose and Requim. Yes, this is an old story, but well worth the read.

From the Washington Post:

BERLIN -- The first person to recognize that Anneliese Michel was possessed
by demons was an older woman accompanying the girl on a pilgrimage. She noticed
that Anneliese would not walk past a certain image of Jesus, refused to drink
water from a holy spring and smelled bad -- hellishly bad. An exorcist in a
nearby town examined Michel and returned a diagnosis of demonic possession. The
bishop issued permission to perform the rite of exorcism according to the Roman
ritual of 1614.

Half a year and 67 rites of exorcism later, Michel was dead at
23.