Paul Tremblay’s psychological horror/exorcism novel Head Full of Ghosts is finally getting a film adaptation. As this book has already been named one of the best novels of the 21st century by me, horror fans should all be really excited about this one. Here’s everything we know so far!

Paul Tremblay’s 2015 Bram Stoker Award-winning novel Head Full of Ghosts follows the Barretts, a middle-class suburban family whose lives are turned completely upside down when 14-year-old Marjorie Barrett becomes afflicted with a mysterious mental health condition. When doctors can’t provide the family with any help, they begin to wonder if Marjorie might be a victim of demonic possession, and they invite a reality TV show called The Possession to document her exorcism.

A film adaptation of this book has been in the works for several years. In 2018, Osgood Perkins was attached to direct. Then in 2020, Scott Cooper came on board to rewrite and direct the film, with Margaret Qualley in talks to star. By 2024, the baton was passed to the directing duo Veronika Franz and Severin Fiala, best known for the Austrian film Goodnight Mommy.

Finally, the project seems to be truly underway, and filming is supposed to start this month. Head Full of Ghosts will be produced by Robert Downey Jr’s Team Downey, The Allegiance Theater, and Fifth Season. Lion’s Gate will distribute it. The cast of the film has also been announced; David Harbour, Rebecca Hall, and Esmé Creed-Miles are all in final negotiations to star.

Paul Tremblay shared the news on Instagram: “I’ve read the screenplay; it’s wild, and I love it. I can’t wait to see Franz and Fiala put it all on screen. Big thanks to @theallegiancetheater and @officialteamdowney and @dgams54 working so long and hard to make it into scary ass movie!”

Excited to find out more? Head Full of Ghosts now has an Instagram page, and you’d better believe I will be stalking it for updates.

In the meantime, here are some upcoming 2026 horror adaptations you should check out!