There are multiple possession/exorcism-based films that fall into ... One other explanation for people believing that "Insidious" is based on a true story is that they're getting it mixed up ...

Exorcism of Evil Spirits: The True Story of Curses That Really Happened Volume One Exorcism of Evil Spirits: The True Story of Curses That Really Happened Volume Four Exorcism of Evil Spirits ...

Based on the archives of Father Gabriele Amorth, The Vatican Exorcist plunges Russell Crowe into an investigation combining possession and occult mysteries. An esoteric horror film, to be released on ...