Nearly every Sunday since he was 7, Connor McIlwain had panicked about going to school the following day.

The noise of barking dogs or crying babies, the demands of school and the constant fear of being exposed to one of his phobias was a lot for Connor to handle. Diagnosed with autism at age 3, he would get so upset at school that sometimes he would run into the street; on at least one occasion, he narrowly escaped being hit by a car.

Connor’s mother, Lori McIlwain, recorded one of his Sunday-night tantrums when he was 10 to share with his doctor. “Poof me away. Poof me away,” Connor pleads in the audio clip, his voice strained. “I want to leave school forever. Throw me away forever; I really want to go away forever.”

The doctor offered suggestions on how to calm Connor and prescribed medication. Still, one day last year, Connor, then 17 and a sophomore in high school, became particularly distraught after a confrontation with a teacher. “We got the call from the school and picked him up,” McIlwain says. When he got home, he began trying to harm himself. “He told us, ‘I’m ready to die now,’ and said goodbye to us.”

Connor’s parents had often kept him home from school to prevent his dangerous meltdowns, but after this incident, they pulled him out of school for good. “Connor is a talented kid,” McIlwain says, but “no math or science was worth his life.”

Among people Connor’s age, suicide is the second leading cause of death in the United States, according to the U.S. Centers for Disease Control and Prevention: Approximately 6,159 people between the ages of 10 and 24 died by suicide in 2016. Suicide is the 10th leading cause of death across all age groups and one of just three leading causes of death that is on the rise, according to a June report. But it’s unclear what the statistics are for people with autism.

Studies over the past few years hint that suicidal ideation is more common in people with autism than in the general population, but the estimates vary so widely that some experts say they are meaningless. Still, there is some evidence that autistic people are especially vulnerable to suicide: One 2015 study that mined Sweden’s large National Patient Registry found that they are 10 times as likely to die by suicide as are those in the general population. (Women with autism are particularly at risk, even though men are more so in the general population.)

Even when signs of suicidality are apparent, clinicians may dismiss them.

“I think part of the problem is that we only see things we’re paying attention to,” says Jeremy Veenstra-VanderWeele, professor of psychiatry at Columbia University. “Until very recently, we didn’t expect to see it, so we didn’t see suicidality in patients with [autism]; it just wasn’t on our radar.”

Clinicians may wrongly assume that people on the spectrum don’t have complicated emotions, or may discount their outbursts, says Paul Lipkin, director of the Interactive Autism Network at the Kennedy Krieger Institute in Baltimore, Maryland. “These children feel a normal range of emotions as other children, but [they] don’t do it in a typical way, and they’re not necessarily taken as seriously because they have a wide range of emotions showing already,” he says. Doctors also misinterpret self-harm — a classic warning sign for suicide in the general population — as a part of autism.

All of that is beginning to change. Some teams are adapting tools to spot autistic people who are at risk of suicide and gain a sense of the scale of this problem. Many typical signs of suicidality — changes in sleep, appetite and social relationships — involve areas that are already challenging for these individuals. So “one can’t rely on these changes in this population,” Lipkin says. Instead, the researchers are looking at the interplay of known risk factors, such as depression, anxiety and bullying, in autistic people. And they are identifying risks unique to this population, such as social challenges, communication difficulties and a diagnosis of attention deficit hyperactivity disorder.