Susannah Cahalan
Susannah is the autobiographical protagonist of the book. Over the course of the story, she recounts her struggle and recuperation after she was diagnosed with a rare autoimmune disease. She wakes up in a hospital with no memory of the past month, a terrifying thought. Eventually, she is diagnosed with a form of brain inflammation: Anti-NMDA receptor encephalitis, which is where the book's title "Brain on Fire" comes from. The book details her journey to recovery and learning to live with her disease.
Dr. Souhel Najjar
During Susannah's initial stay in the hospital, she is misdiagnosed several times. Dr. Najjar is the one who eventually diagnoses her correctly with an autoimmune disease, conducting specific tests such as making Susannah draw a clock. When Susannah drew all the numbers on the right side, Dr. Najjar's suspicions were confirmed.
