Even though the brain stops growing in size by early adolescence, the teen years are about fine-tuning how the brain works, according to the National Institute of Mental Health.

Untreated brain injuries or multiple brain injuries can disrupt teen brain development if they are severe enough. A traumatic brain injury can impact a young person’s health, thinking and behavior, which controls learning, self-regulation and social participation, according to the Centers for Disease Control and Prevention.

The brain finishes developing and maturing in the mid- to late 20s. One of the last parts of the brain to develop is located behind the forehead called the prefrontal cortex, which is responsible for skills like planning, prioritizing, impulse control and long-term decision making. For teens, this means they might have a harder time making well-thought out decisions than someone with a fully developed brain.

Children and teens are incredibly vulnerable to head injuries and hundreds of thousands of children visit the emergency room every year due to brain trauma, according to the Brain Injury Association of America.

Middle Park Health trauma medical director Dr. Michelle Lupica said a good night’s rest is critical to recovering from a brain injury — something that many teenagers struggle with.

“Sleep is what helps your brain restore itself. When they’re not busy being sleep deprived, they’re all on their devices all the time, and that is not brain rest,” Lupica said. “… I think specifically those two things, being on your device and being sleep deprived, sort of make it a special case for teenagers.”

While Lupica doesn’t want to scare teenagers from doing sports or other activities they love, she does want to send the message that brain injuries are a serious matter.

“You could end up with chronic depression,” Lupica said. “You could end up with chronic headaches. You could end up with chronic disequilibrium, where you can’t really tell where you are in space. You could end up having cognitive difficulties.”