In 1977, Janet Hodgson was just like every other 11-year-old girl in Enfield, England ... except for the poltergeist that spoke through her and haunted her family. This weekend James Wan's The Conjuring 2 opens in theaters worldwide. Its predecessor was inspired by real-world events and people, including paranormal investigators Ed and Lorraine Warren. The sequel follows in those footsteps; it's loosely based on the Hodgson family's story, which was widely shared in the press as it occurred, and has since been discussed in books and in documentaries as the "Enfield Poltergeist."
According to Film School Rejects, the Warrens (who reportedly investigated more than 10,000 cases during their career) did visit the Hodgsons to witness the possession, but they weren't actually key players in the family's story. The main non-familial character in the real-life story (who is also portrayed in the film) was a man named Maurice Grosse, a member of the Society for Psychical Research. He, along with fellow member and author Guy Lyon Playfair, investigated the poltergeist and recorded interviews with Janet and the rest of the Hodgson family. The video below is a segment taken from a BBC documentary about the Enfield Poltergeist that includes footage shot by Grosse. In it, Janet (who speaks in a deep voice) sits alongside her sister Margaret as they discuss what they've witnessed.
The website History vs Hollywood used the theatrical trailer and a YouTube sneak peek for The Conjuring 2 to see which early images of the film are based in reality and which are completely fabricated for the sake of the film (be warned, there are some spoilers). For example, the shot of the room full of wooden crosses turning upside down on their own reportedly did not happen in Enfield. The real Janet Hodgson did speak in a strange voice, but it has been exaggerated for the movie with shaking furniture and flashing lights that are not true to life.
The historical events have been dissected by skeptics and called a hoax by many, but some who witnessed them held that the poltergeist was legitimate, even the real Maurice Grosse, who caught Janet and her sister faking some of the events when they didn't know they were being recorded.
[h/t Film School Rejects]