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 auto-immune disease, anti-NMDA receptor encephalitis. She published a second book, The Great Pretender: The Undercover Mission That Changed Our Understanding of Madness, in 2019. When she is not writing longer works, she works as a writer for the New York Post. Cahalan's work has raised awareness for her brain disease, making it more well-known and decreasing the likelihood of misdiagnoses. ()