Susannah Cahalan (born January 30, 1985) is an American journalist and author, known for writing the memoir Brain on Fire, about her hospitalization with a rare auto-immune disease, anti-NMDA receptor encephalitis. She has worked for the New York Post.A feature film based on her memoir was released in June 2016 on Netflix. Chloë Grace Moretz played the role of Cahalan. In 2019, Cahalan's second book was published, The Great Pretender: The Undercover Mission That Changed Our Understanding of Madness. In the work she posthumously accuses prominent psychologist David Rosenhan of fabricating the results of seminal research published in the journal "Science". Rosenhan's work demonstrated that staff working at psychiatric hospitals, including psychiatrists, could be easily misled to diagnose schizophrenia when individuals were perfectly sane and reported the mistreatment of patients in these facilities. Rosenhan was, himself, a participant in the research which involved test subjects ceasing to present symptoms of mental illness after admission to the hospital and then observing the manner in which they were treated by staff at the institutions. Cahalan was drawn to this study due to her own experiences with being improperly diagnosed with mental illness, but as she researched Rosenhan and his activity, she began to find contradictions in his work that made her question the validity of his experiment.