Susannah Cahalan

Susannah Cahalan (born January 30, 1985) is an American writer and author, known for writing the memoir Brain on Fire: My Month of Madness, about her hospitalization with a rare autoimmune disease, anti-NMDA receptor encephalitis. Her second and third books, The Great Pretender: The Undercover Mission That Changed Our Understanding of Madness and The Acid Queen: The Psychedelic Life and Counterculture Rebellion of Rosemary Woodruff Leary, were published in 2019 and 2025, respectively. She also works as a writer for the New York Post. Cahalan's work has raised awareness for her brain disease, making it more well-known.

Personal life and career Cahalan was a journalist for the New York Post before she became ill, and her editor suggested that she write about her disease and its effect on her. As she recovered from her brain illness, she decided to bring the same journalistic approach to writing her memoir, using fact and research as the foundation for her story. According to Cahalan, it was a "very dissociative process" to write about her experience with the disease. She had to recreate the timeline of everything that happened, gathering different records from the hospital to keep track of what happened and when. Through interviewing those closest to her, she was able to piece together what that month looked like. Overwhelmingly, what she remembered from her disease was the fear and anger that it created within her. Writing her book, she said, felt like regaining control over the body that had controlled her for so long.

Cahalan wrote more articles for the New York Post. She gave a lecture at the opening session of the American Psychiatric Association's 2017 meeting. She presents talks for hospitals and universities to raise awareness about her disease. In 2022, she resided in Brooklyn, New York.

Anti-NMDA receptor encephalitis Disease presentation and misdiagnoses Cahalan's disease manifested in 2009 when she was 24 years old. It began with sensory issues, which she later described in her article "My Mysterious Lost Month of Madness" as experiencing the world “brighter, louder, more painful.”

The Great Pretender

In 2019, Cahalan's second book was published, The Great Pretender: The Undercover Mission That Changed Our Understanding of Madness. In the work she accuses 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. 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.