The first time it happened, I was 8. I was tucked in bed reading my favorite book when my tongue swelled up to the size of a cow’s, like the giant tongues I had seen in the glass display case at the neighborhood deli. At the same time, the far wall of my bedroom began to recede, becoming a tiny white rectangle floating somewhere in the distance. In the book I was holding, the typeface grew vast on the page. I was intrigued, I remember, but not afraid. Over the next six years, the same thing happened to me dozens of times.

Forty years later, while working as a science writer, I stumbled on a scientific paper describing almost exactly what I had experienced. The paper attributed those otherworldly sensations to something called Alice in Wonderland syndrome, or its close cousin, Alice in Wonderland-like syndrome.

People with Alice in Wonderland syndrome (AWS) perceive parts of their body to be changing size. For example, their feet may suddenly appear smaller and more distant, or their hands larger than they had been moments before. Those with the closely related Alice in Wonderland-like syndrome (AWLS) misperceive the size and distance of objects, seeing them as startlingly larger, smaller, fatter, or thinner than their natural state. People who experience both sensations, like I did, are classified as having AWLS.

The syndrome’s name is commonly attributed to English psychiatrist John Todd, who in 1955 described his adult patients’ illusions of corporal and objective distortions in a paper in the Canadian Medical Association Journal. He named the collection of symptoms after Lewis Carroll’s protagonist Alice in Alice’s Adventures in Wonderland, who went down a rabbit hole and found herself shrinking or expanding depending on her circumstances.

Grant Liu, a pediatric neuro-ophthalmologist at the Children’s Hospital of Philadelphia, recently began studying children with AWS. His patients, including those with AWS, often come to him through referrals from other specialists, like neurologists or ophthalmologists, who are looking for Liu to confirm a diagnosis or to help find one.

A diagnosis of AWS, which usually sets in at a young age, requires that a child have the characteristic symptoms of the syndrome and be “completely normal” in all other ways (meaning they have no other conditions like a stroke or a brain tumor), Liu says—which means that he must rely on what his pediatric patients tell him to make an accurate diagnosis. The syndrome doesn’t reveal itself through brain imaging, such as MRI or CT scans, he says, and while researchers have also studied recordings of brain activity to see if a particular pattern of electrical impulses appears in AWS patients, none has been found.

But the stories that his young patients tell him are usually consistent with one another, which gives even the youngest ones credibility. “What interests me most is that the symptoms different kids describe are very, very similar,” Liu says. “This is why I don’t think they’re faking it. When a 6-year-old says, ‘Mommy’s head is small, or things look far away,’ how do they know to say that [if it’s not true]?”

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If current scientific literature is any measure, AWS is rare. Not much has been written about it in peer-reviewed papers. But based on his experience, Liu believes it may be more common than the literature indicates. “There are a lot of kids with this,” he says. “I think it’s a lot more common than we think.” Liu suspects that the syndrome’s relative obscurity may be due to the fact that AWS and AWLS are usually harmless, disappear on their own, and are rarely debilitating. There’s also no treatment: Patients aren’t medicated, and no surgery is prescribed. Typically those with the syndrome live with the symptoms until they subside, often in the late teens.

But Liu found the syndrome interesting enough to begin tracking his patients and collecting data on those he had diagnosed. In a small study that appeared in 2014 in the journal Pediatric Neurology, he and his collaborators identified 48 children that Liu had diagnosed with AWS or AWLS between 1993 and 2013. Their average age at diagnosis was 8, and their most common symptoms were micropsia (when objects and body parts appear smaller than they actually are) and teleopsia (when objects appear much farther away than they are).

Liu followed up with 15 of the patients and found that the symptoms continued in one-third of them, and, intriguingly, four of the 15 patients had also developed frequent migraines. Now, he and other researchers believe that migraines, as well as other conditions like epilepsy and viral infections, may be associated with the syndrome. In fact, a 1977 paper in the journal Clinical Pediatrics characterized AWS as a symptom of mononucleosis in three patients, all of whom experienced visual distortions just before the usual telltale signs of the virus kicked in. Likewise, three patients of Todd’s had a family history of migraine, or epilepsy, or both.

One of those researchers, neurologist Owen Pickrell, points out that these conditions may also be associated with epilepsy. Pickrell, who does not work with Liu, is a clinician and genetic researcher at Swansea University in the United Kingdom. His research focuses on epilepsy’s genetic component, but he’s also interested in determining whether there’s a genetic link between epilepsy and AWS.

Over the past 10 years, Pickrell and his research group, led by Mark Rees, a professor of molecular neuroscience at Swansea, have studied roughly 100 families with multiple members who have epilepsy. What recently caught their attention was a family whose members have both epilepsy and AWS. “We thought there might be a genetic link,” Pickrell says. “So, we started to delve into it much deeper, making inroads. We thought if we could figure out what gene causes Alice in Wonderland Syndrome, we could work out what that gene does in the brain, and then we might find links to serious diseases.”

Three years ago, to test their hypothesis, Pickrell and his colleagues began recruiting people who had been diagnosed with AWS and AWLS to donate saliva for genetic analysis. Thus far, 15 people have mailed in their saliva. Pickrell’s team is now in the midst of analyzing the data gleaned from their samples, a project that they say is only a start to more rigorous future research.

Despite the small size of the current study, Pickrell says it has allowed him to get well-acquainted with the syndrome. Among the people in his study and other patients he has spoken to, he says, AWS and AWLS tend to begin between the ages of 5 and 10 and then ebb in the late teenage years. But he says that in other cases he’s come across, including those of some patients with epilepsy, the syndrome may return later in life, either from stress or from the brain changes that naturally occur as a person ages.

Pickrell has also noticed that the symptoms of AWS and AWLS tend to occur at night (as it happened to me, without fail). He suspects that the syndrome may be triggered by a combination of changes in sensory input—like the ebbing of noise and light at nightfall—and the chemical changes that occur in the brain as we near sleep. For example, we depend on sight and sometimes touch to determine the size or distance of an object, Pickrell explains, meaning that if sensory input is disrupted, our perception of that object changes. “So, if you close your eyes and your arm feels small, and then you open your eyes, you get more input, and that tells you your arm is really bigger.”

Some people Pickrell has talked with say they can control their symptoms by opening or closing their eyes—which is exactly what I did when I grew tired of the distortions. Other times, I enjoyed the sensations, and could prolong them simply by staying still.

Both Pickrell and Liu say some of their patients were reluctant to tell anyone about the symptoms because they were afraid people “would think they were nuts,” Pickrell says. And some, when they did mention the syndrome to their families, found that one or both parents had also had AWS or AWLS.

This wasn’t the case for me. When I told my father and older sister about my symptoms—it hadn’t occurred to me to keep them a secret—neither had any idea what I was talking about, and they didn’t think it was serious enough to take me to the doctor. Years later, my sister told me she had assumed it was only my imagination running wild. But for other families, a diagnosis of AWS can come as a relief. Even when neither parent has experienced the syndrome, their reaction is “uniformly positive,” says Liu. “[The parents] are fearing the worst. They’re fearing a brain tumor or a stroke, and I’m able to say, ‘Your kid doesn’t even need an MRI or an EEG.’ And they love that. They’re reassured because they have a diagnosis, and the kid is going to be okay.”

Both Liu and Pickrell believe that the medical community is becoming more interested in AWS and AWLS. Over the last few years, Liu says, he has noticed an uptick in the number of scientific studies on the subject, though he’s not sure why—perhaps because this strange condition is still something of a mystery, or perhaps because of its possible link to other, more serious diseases. Or maybe the reason has little to do with the science at all: “It has a catchy name,” Liu offers. “If we had a more complicated one, I don’t know if people would be all that interested.”