Nearly half of teens with autism who rely on mental health services receive them at school, leaving them particularly vulnerable when it’s time to transition to adulthood, according to a new study.

Of teenagers with autism, 46 percent receive mental health services to deal with everything from behavioral issues to concurrent mental health disorders, researchers from Washington University in St. Louis report in this month’s issue of the journal Psychiatric Services.

Schools provide the services for about half of these children, the study found, and are particularly likely to be the source of assistance for black students and those who come from low-income households.

The findings represent the first national look at the use of mental health services in young people with autism, researchers said. They are based on an analysis of a U.S. Department of Education study of nearly 1,000 students ages 13 to 17 with autism from across the country who receive special education services.

Researchers behind the study indicate that a reliance on schools for mental health services can put students in a perilous position when they transition to adulthood, making effective preparation critical.

“Those that have accessed services at school are especially at risk for service discontinuities as they lose access to services through the school,” said Sarah Narendorf, a social work doctoral candidate at Washington University who worked on the study.