AceShowbiz -

Scott Stapp opens up about his erratic behavior in the past few years. The Creed vocalist tried to kill himself in 2012, was placed on a psychiatric hold, and lost custody of his children after he ranted in a disturbing video last year about being broke and homeless.

He was diagnosed with bipolar disorder when undergoing treatment. "It was hard to process," he said to PEOPLE. "There's a stigma associated with it. But [his wife] Jaclyn kept telling me, 'Embrace it. We love you.' It became a big sign of relief, because finally, we had an answer."

Stapp also struggled with alcohol and drug addiction. "I had a psychotic break that was brought on by alcohol and drug abuse," the rocker explained. "I was hallucinating. I drove around the United States for a month, following an angel that I saw on the hood of my car."

"In my delusional thinking, I thought my family was involved in ISIS, and that millions of dollars had been taken from me to support terrorism," he added. "All of it was nonsense. I was out of my mind."

Stapp is now undergoing an intensive therapy and taking medication for bipolar disorder. "Nothing is more important than my sobriety," so he said.