A MOLECULE AWAY FROM MADNESS Tales of the Hijacked Brain By Sara Manning PeskinOn an ordinary day in August 2016, Lauren Kane was sucked into a zombie apocalypse. The recent college graduate and aspiring fiction writer had moved back into her mother’s house; she spent her days polishing short stories and binge-watching episodes of “The Walking Dead.” That morning she had woken up, eaten breakfast and gone back to bed. “What’s for breakfast?” she inquired when she reappeared. Lauren slept still more, awakening for the third time around midday. “What’s for breakfast?” she asked again. By that evening she was running a fever and had become unsteady on her feet. Her mother took her to the E.R., where Lauren calmly answered a doctor’s questions. In her first book, “A Molecule Away From Madness,” the neurologist Sara Manning Peskin describes what happened next.“Suddenly, as if occupied by a spirit, Lauren reached for the doctor’s chest and gripped his shirt. She thrust him across the room, then dug her fingernails into the arm of a startled nurse. Her mother moved to calm her, but Lauren pushed her to the floor.” Security guards rushed to the scene. Lauren turned and pointed to one of them, yelling, “Don’t you see it, she’s a walker.” One guard asked if she was high on PCP, while another pieced together the patient’s pop-culture reference: “Oh my god. … She thinks she’s in ‘The Walking Dead.’”Lauren was not on phenylcyclohexyl piperidine, the hallucinogen known as PCP — but her own body was producing a molecule that generated a similar effect. A tumor growing on her right ovary had stimulated her immune system to produce millions of antibodies, which mistakenly attacked crucial receptors in her brain. Lauren was the victim of a molecule gone rogue.Such errant molecular activity underlies many serious mental afflictions, notes Peskin, an assistant professor of clinical neurology at the University of Pennsylvania. “The very molecules that make our brains work can also co-opt our personalities and destroy our ability to think,” she writes. (After Kane’s tumor was surgically removed, she slowly regained touch with reality.)The author divides these “molecular villains” into four categories. “Mutants” are altered DNA sequences; they can give rise to conditions like Huntington’s disease and frontotemporal dementia. “Rebels” are aberrant proteins, such as the one that caused Kane’s psychosis; they can lead to scourges like Creutzfeldt-Jakob disease, a neurodegenerative disorder that is inevitably fatal, usually within a year of its onset. “Invaders” are foreign substances like “environmental toxins, illicit drugs and pharmaceuticals”; they can produce pathologies like mercury toxicity. And “evaders” are essential components, like vitamins, that wreak havoc when they go missing. A thiamine deficiency, for example, can lead to the development of Korsakoff’s syndrome, one symptom of which is confabulation: Sufferers make up fantastical stories, believing them to be true.Peskin writes about these conditions and the patients consumed by them with a grace and humanity that recall Oliver Sacks. Her slim volume also manages to tell the stories of the doctors and researchers who chased down these treacherous molecules in the field and in the lab; she has a flair for the quick character sketch and an eye for vivid detail.The sole person left out of this compelling account is the author herself. It’s only in a footnote to the Lauren Kane story that we discover that she was Peskin’s patient; the main body of the tale is told from an artful distance.Kane’s doctor is a dazzling stylist and a compassionate observer. In her next book, perhaps she’ll show us more of what’s going on in her own mind.