United Kingdom, March 20 -- Billy Idol believes he may have become a drug addict due to undiagnosed ADHD.

The Rebel Yell singer - whose years of excess and struggles with addiction are documented in new documentary Billy Idol Should Be Dead - has spoken openly about his dependency on heroin and other illegal substances, and after his son William was diagnosed with Attention Deficit Hyperactivity Disorder as a child, Billy has pondered whether his offspring inherited the neurodevelopmental brain disorder from him.

He told The Times newspaper: "I think I might have an ADHD problem too.

"That could have been a reason I was, you know, taking drugs in the first place, maybe because they do help you to focus. And I could never focus on anyth...