Megadeth were among the core bands credited with inventing thrash metal. Alongside Metallica, Anthrax and Slayer they became known as the 'Big Four' the founding fathers of a harder, faster more aggressive take on the genre. Dave Mustaine was the original guitarist in Metallica and after being fired – due to excessive drug use, heavy drinking and aggressive attitude – went on to form Megadeth with bassist David Ellefson in 1983.

Over the next 30+ years Megadeth released 14 studio albums (album 15, Dystopia, is released in January 2016) and sold over 50 million records worldwide. Though it hasn't always been plain sailing, Mustaine has battled addiction throughout his life, there have been multiple lineup changes (there are almost 20 former members listed on Wikipedia, even Ellefson tried to sue Mustaine when he left Megadeth in 2002). Now after 17 trips to rehab Mustaine has been clean and sober for years, with Ellefson back in the lineup alongside Lamb of God's Chris Adler on drums and Brazilian guitarist Kiko Loureiro. And Mustaine can't wait to get back to Glasgow.

How would you describe Megadeth's music?
To me it's punk rock, heavy metal, jazz and classical. Growing up listening to punk rock and going surfing listening to heavy metal and loving jazz's weirdness and the majesty of classical stuff just gave you so many different colours, a huge palette to go to when writing songs. So we had tons of influences which gives us all those twists and turns, inversions and crazy time signatures.

At the time did you realise you were inventing a new style of playing?
The reason I got into playing music was because my sister played piano. She played it very badly, so I started playing guitar to drown out the noise. All I really knew was I was keeping my head from exploding.

How's the new lineup shaping up?
It's funny when you make a change like this there's a fear of the unknown. So you're kicking the tires and everything looks great then you get ready for the first road trip, that's the moment of truth: did I pick the right guys? Is this a guy who will be my brother out there? Who will be willing to handle the stress and lack of sleep? But it's good, so so good.

You're touring the UK with Lamb of God so Chris Adler will be playing two sets every night. How's he holding up?
Chris brings a lot of joy to my life, he's a professional and a wonderful human being, he can drum for a very long time [laughs]. I'd be lying if I didn't say I wanted him full time in Megadeth, he's just that good of a player.

In 2002 an injury led to severe nerve damage in your left arm. What was it like when doctors said you'd never be able to play again?
It was life changing. For 17 months I couldn't play the guitar at all, the physical therapy was gruelling. But the only one who can tell me I can't do something is me. So when the doctor initially told me that I would get ‘80% back’, I thought he meant 80% of my playing but he was like: ‘oh no son you'll never play again, I was saying you'd get 80% of the use in your arm back.’ I was like ‘fuck that I'm not going to take that lying down no one is ever going to tell me I'm not going to play again.’ So I went on a very intense programme of physical rehabilitation and thank god it worked.

And how did that experience change you?
It's a catalyst of sorts. Those are the moments that motivate me as a person, it made me recognise that life is short. If I have a dream no one can tell me I can't. I can show our fans that even with my fucked up situation growing up that you can be successful. My mom was a maid, we lived on food stamps, I've been homeless, totally fucked up, an addict and here I am sober – I'll have a glass of wine now and again or a beer at dinner – but to turn that around alone from homeless to happily married with two children who have grown into well-adjusted adults fitting into society – you would think my kids would be some awful kids from the Adams Family or something, but they're great – and I owe so much of that to my fans and their loving support.

Looking forward to playing Glasgow?
So much. We're looking forward to Glasgow for a lot of different reasons. My wife and daughter are coming over, we moved to Tennessee recently because [daughter] Electra is pursuing a country [music] career and she'll be filming some footage for a video in Glasgow. I particularly like going to Glasgow because my brother-in-law, Bob Wilkie, who married my middle sister, is Scottish. Big, tall, six foot plus, he was the chief of police in Stanton [California], a proud man, didn't take shit from anybody, tough as nails. So I love that ruggedness he taught me as a kid. I love the history and culture of Glasgow and all of Scotland.

Is there a theme or statement you want to make with upcoming album Dystopia?
The theme would be real simple: dominate the world.

Dystopia is released 22 Jan, 2016 on Tradecraft via Universal