Mike Portnoy can't regret leaving Dream Theater because he'd always have wondered "what if?" without the sensational move.

The drummer and co-founder astonished fans when he quit in 2010, leading to a public war of words, and even an attempt to rejoin – but he was ultimately replaced by Mike Mangini. He's since forged a career with supergroup the Winery Dogs, while continuing to work with Transatlantic and Flying Colors, among others. Dream Theater have released two albums since the lineup change.

Portnoy tells Rocksverige: "There are lots of actions you take in your life and if it brings a result you didn't want, or you weren't anticipating, it's not something you should regret. It's just something you should learn from.

"There's a lot of things in my life that I've learned from and, ultimately, I don't regret them, because they got me to where I am right now. I'm as happy as I've ever been and as musically fulfilled as I've ever been.

"I'm not going to use the Dream Theater example because I can already see the headlines, so I won't say it. I'll paraphrase like this – when I came to that crossroad four years ago, if I hadn't made the decision, I probably would have spent the rest of my life wondering, 'What if? What if I'd left the band?'

"I think it's better to follow your heart and take the risk than wonder what could have been."

Portnoy recently hit back at fans who called him a "sellout" over his involvement with the Tweet Secret app, which charges fans for access to exclusive content.