Use of cocaine and marijuana may contribute to the risk of stroke in young adults, a new study suggests.

Researchers examined 20 years of data from 2,200 adults ages 18 to 54 who had a stroke. Drug use in this group rose from 4.4 percent in 1993-1994 to 30.3 percent in 2015. During the same period, use of alcohol and cigarettes remained stable, HealthDay reports. The findings were presented at the American Stroke Association’s international conference.

“It’s concerning. We need to be doing more to curb this growing problem, and young people especially need to be aware that illicit substances are associated with an increased risk to your health — specifically, the risk of stroke,” said lead author, Dr. Felipe De Los Rios La Rosa.