Deryck Whibley was convinced he had ''killed the part of [his brain]'' that wrote songs after becoming seriously ill due to drinking.

The Sum 41 frontman - who has suffered with on-going alcohol abuse in the past - had to relearn the guitar and find his voice again after a stint in intensive care in May 2014, which saw his body ''shut down'', and even now it takes him longer to write music than it used to.

Talking about his recovery, he said: ''By the evening, I would start trying to write music again, which was torture.

''Even right now, if I was to say I was going to write a new record, it's going to take a couple of weeks and a lot of bad songs until one turns into something OK. Then it gets better and better.

''During that process, it was so much further away.

''Whatever was coming out, I would be like, 'This isn't even a riff'. Nothing was coming and that was going on for months.

''I was convinced it was gone and I had killed that part of my brain.

''Sure enough, slowly something came. It was a riff and it was useable.

''I still had something left and I could use it. Then it just grew and grew.''

The 40-year-old rocker needed physio every day for months to learn to walk and talk again.

He added to Rock Sound magazine: ''It was really painful. My days would consist of me waking up and doing physiotherapy.

''At the very beginning, I wasn't even trying to walk because I knew that I couldn't.

''That's when I was trying to talk and I couldn't. ''My motor skills were all f***ed up and I was trying to have conversations and couldn't.

''A physiotherapist would come over to the house every day and we would work on small exercises, building up muscles in my legs and feet.''