The singer said she has never told anyone before.
Lady Gaga recently visited an LGBT homeless shelter to speak to the young people living there.
While at the Ali Forney centre she spoke about her own personal pain and how it helped her empathise with others.
“I love to give things to people that have nothing or less than me. These children are not just homeless or in need. Many of them are trauma survivors; they’ve been rejected in some kind of way,” she said.
“My own trauma in my life has helped me to understand the trauma of others.” She added, according to Today.
The singer has spoken openly about being raped when she was 19, and told the young people in the shelter about how it affected her.
“I told the kids today that I suffer from a mental illness. I suffer from PTSD. I’ve never told anyone that before, so here we are,” Gaga said.
“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.”
PTSD stands for post-traumatic stress disorder. It is a mental health condition that’s triggered by experiencing or witnessing a traumatic event. Symptoms may include flashbacks, nightmares and severe anxiety, as well as uncontrollable thoughts about the event.
Lady Gaga also donated some of her clothes to the shelter and performed some songs for the people there.
She explained that as well as the help of her friends and doctors, being kind aided her journey.
“I’d been searching for ways to heal myself. I found that kindness is the best way. The one way to help people that have trauma is to inject them with as many positive thoughts as possible.” She said.
The 30-year-old also recently spoke about suffering from chronic pain.