On May 1 , 2014 , '' Deadline '' reported that Charlize Theron had acquired the film rights to Susannah Cahalan 's 2012 memoir '' Brain on Fire : My Month of Madness '' . Dakota Fanning was set to play Cahalan , a young woman who one day wakes up in a hospital with no memory of the events of the previous month . Theron would produce along with Beth Kono and A.J. Dix through her banner Denver and Delilah Productions . On January 22 , 2015 , Irish filmmaker Gerard Barrett was set to write and direct the adaptation , while Rob Merilees of Foundation Features would produce and finance the film . London-based Mister Smith Entertainment sold the film to international distributors at 2015 Berlin Film Festival . Will Poulter was added to the cast on February 4 , 2015 , to play Cahalan 's boyfriend . On May 26 , 2015 , Thomas Mann and Jenny Slate were reportedly in talks to join the film , where Mann would play Cahalan 's boyfriend , replacing Poulter . On June 26 , 2015 , it was announced that Dakota Fanning had left the project due to scheduling issues , and Chloë Grace Moretz replaced her for the lead role . On July 7 , 2015 , it was announced that Broad Green Pictures had come on board to produce and finance the film as well as distribute the film in the United States , while Lindsay Macadam would also produce along with producing partner Merilees . On July 16 , 2015 , Carrie-Anne Moss and Richard Armitage were cast as Cahalan 's parents , Rhona Nack and Tom Cahalan , respectively . On July 20 , 2015 , Tyler Perry joined the film to play Richard , Cahalan 's boss at the '' New York Post ''
2015 Berlin Film Festival
65th Berlin International Film Festival
Brain on Fire (film)