Black Sabbath bassist Geezer Butler is one of the most confident bassists ever. His nimble fingers know their way around a fretboard, and he plays just as hard as Tony Iommi, making the bass a s prominent an instrument as the guitar. However, in an interview with Classic Rock magazine, Butler admits that he wasn’t always so confident, admitting that depression led to him self-mutilating, and that one of their biggest songs, 1970’s “Paranoid,” was written about his mental state at the time:

“I used to be a cutter. I’d cut my arms, stick pins in my fingers, that kind of thing. I used to get really depressed and it was the only thing that could bring me out from it. If Sabbath hadn’t made it, I’d have been long dead. I’d have killed myself.”

Elsewhere in the interview for the magazine, of which Black Sabbath are on the cover of, Ozzy Osbourne says that Tony Iommi’s cancer scare in 2012 has made him a lot calmer than he’d previously been:

He’s changed so much. He used to be the Darth Vader of the band. What he said went, but he’s got really humble. When you get something like cancer, it fucking shakes your tree.”

Sabbath are in the midst of their final tour, which will see them playing the first-ever Ozzfest meets Knotfest as their last California show.