In American college admission essays, young adults typically reflect on personal challenges they’ve faced. But many recent applicants have also had to grapple with a new, grim reality: surviving mass shootings.

In the 20 years since the deadly attack at Columbine High School in Colorado in 1999, dozens of school shootings have occurred across the United States.

Countless students have been affected by shootings in their communities, including Kyle Kashuv, who attended Marjory Stoneman Douglas High School in Parkland, Fla., where a gunman killed 17 people in 2018. Mr. Kashuv wrote about the experience in his successful application to Harvard College, though the school later rescinded his acceptance.