In 2010, after more than a decade of controversy, Swedo convened a group of colleagues to revisit the PANDAS diagnostic criteria. Physicians, patients, and their families had been “left confused” by the scientific shouting match, they later wrote in the journal Pediatrics & Therapeutics. Sick kids weren’t getting treated; researchers were having a tough time designing and funding rigorous studies. The group’s solution was to scrap the taboo letters in the PANDAS acronym, the ones standing in for “autoimmune” and “associated with streptococcal infections.” Rather than naming the condition for its supposed cause, they’d name it for its presentation in patients.

The clearest and most common characteristic was rapid onset: A kid could be himself one day and a stranger the next. That became the centerpiece of the new name, PANS, or pediatric acute-onset neuropsychiatric syndrome. The diagnosis was meant to be broad, allowing for a range of possible triggers—infection with strep or another microbe, environmental factors, metabolic disorders. PANDAS, in other words, wasn’t going away; it was just becoming a subset of the larger syndrome.

Swedo and her colleagues included a handful of children’s drawings in their paper, made before, during, and after the kids got sick. One triptych is especially moving, a course of illness in miniature. The “before” image shows a dark-haired woman in a teal cocktail dress, her cat-eye makeup meticulously rendered. The “during” image, drawn in the midst of a flare-up, feels addled by comparison. There are no colors or recognizable figures, just squiggles and disembodied eyes. The “after” image shows a girl in a red-striped shirt and sunglasses. She’s standing beside the Eiffel Tower, smiling.

About a week after his visit to the chiropractor in San Francisco, Timothy was sitting in a clinic at Stanford’s Lucile Packard Children’s Hospital telling a trio of board-certified doctors about his hellish ordeal. His life had been turned upside down, he said, but a few days of antibiotics had made him feel himself again. By this point, he told me, he thought of physicians as “clueless.” He’d have won a gold medal in the “100-meter ditch-your-doctor dash,” he said. He had been poked and prodded, his brain scanned, his mind trawled. The medical establishment had belittled his parents, and he felt he had been misdiagnosed and mistreated. So he expected these doctors might dismiss him, too. Instead, the head of the clinic, a rheumatologist named Jennifer Frankovich, promised that her team would help. (Although Frankovich and I are both employed by Stanford, our work has never intersected.)

Alongside Frankovich were Margo Thienemann, a child and adolescent psychiatrist, and Theresa Willett, a pediatrician with a PhD in immunology. The three doctors weren’t shocked by Timothy’s spiral into despair, the sudden psychiatric symptoms and the personality change. They weren’t surprised that psychiatric medicines made him feel worse and that antibiotics made him feel better, or that a multitude of doctors had not been able to offer a single, conclusive diagnosis. This was classic PANS, they said.

The doctors started Timothy on a new course of antibiotics. (Frankovich says she’s always reluctant to prescribe them, though some kids end up needing antibiotics for years.) They also gave him anti-inflammatories and intravenous steroids. Rita felt hope for the first time that year.

Frankovich had started out as a PANS and PANDAS skeptic. As a resident in Stanford’s pediatrics training program in the early 2000s, she’d given a presentation on an article that questioned the link between OCD, tics, and strep. She fell in line with the mainstream thinking, which attributed the disorders to faulty wiring in the brain. Then, in 2010, she met a 13-year-old girl who suffered from the autoimmune disorder lupus. The girl had endured years of treatment with steroids and other harsh medications, including an immune-suppressing drug called CellCept. The side effects had been horrible: Her cheeks ballooned and her belly became distended. Finally, though, she had gone into remission.

But when Frankovich began to taper the dose of CellCept, the girl became depressed; she found it hard to read, remember, and think. Frankovich upped the CellCept and started intravenous steroids again. “Right in front of my eyes, all those mental illness symptoms melted away,” she says. The same thing happened with a 10-year-old boy who had an inflammatory disease of the spine. Overnight, he had developed OCD and tics. Frankovich called his pediatrician and mentioned Swedo’s research. The pair treated the boy with steroids. His symptoms melted away. To Frankovich, this suggested a sobering possibility: Thousands of sick kids around the country were being treated with psychiatric medications while the underlying cause of their illness—inflammation—went unnoticed.