One in five American young adults under the age of 25 lives with a mental illness or behavioral disorder, NBC reports, citing the Centers for Disease Control and Prevention.

The big picture: Per the CDC's research, the state of young adult mental health in the U.S. is only worsening, with the suicide rate among teenage girls reaching a 40-year high in 2015. Here's a look at the numbers that tell the story of this crisis.

The numbers: