Lady Gaga: 'I struggle with mental illness every day"

"I told the kids today, 'I suffer from PTSD.' I've never told anyone that before. So, here we are. But, the kindness that's been shown to me by doctors as well as my family and my friends -- it's really saved my life," she said.

Gaga, who brought clothes and gifts to the shelter, said volunteering is a part of her healing process.

"I've been searching for ways to help myself, and I found that kindness is the best way," she said. "I love to give things to people that have nothing or less than me."

Gaga sat with the teens, offered encouragement and opened up about her personal experience of sexual assault.

"Meditation helps me to calm down," she said. "I don"t have the same kinds of issues that you have, but I have a mental illness, and I struggle with that mental illness every day. I need my mantra to help keep me relaxed. You are brave. You are courageous."

In 2012, Lady Gaga and her mother, Cynthia Germanotta, founded the Born This Way Foundation, an organization committed to supporting mental health wellness, empowering young people and encouraging them to spread kindness.