What causes mental illness? We’ve long blamed stress, trauma, and brain-chemistry imbalances. But a new theory is quietly achieving critical mass. In INFECTIOUS MADNESS, award-winning science writer Harriet Washington reveals that schizophrenia, obsessive-compulsive disorder, Alzheimer’s, and anorexia also may be caused by bacteria, parasites, or viruses. Weaving together cutting-edge research and case studies, INFECTIOUS MADNESS shows how strep throat can trigger rapid-onset OCD in a formerly healthy teen and how contact with cat litter elevates the risk of schizophrenia.