He now travels the world telling people that "everyone can change".

Mr Leventhal led 60 yoga enthusiasts on a "transformative journey" during a class at Yoga Loft in Newcastle on Wednesday.

The class raised money for the Oasis Youth Support Network and the Newcastle Bridge Youth and Family program. "I'm in a place of doing more for others and helping them heal and transform," he said.

"I wonder what my life would have been like if I had help available."

Mr Leventhal struggled with drugs, alcohol abuse and people's perception of his sexuality from his teenage years.

Looking back, he sees his life was "full of misery and struggle".

One-night stands and stealing became the norm. He delved into prostitution in the 1980s because it paid for his ice addiction and clients often gave him free drugs.

"I don't regret it because I am where I am now because of it . . . If I changed a single thing I might not be where I am right now."

It took Mr Leventhal several attempts before he stayed clean.

He became a banker and then left the corporate world in search of a meaningful life through yoga.

In his memoir Two lifestyles, one lifetime, Mr Leventhal shares his path from "rock-bottom hopelessness" to "wildly extravagant possibility".

He tells of the confused voice in the back of his mind and his lack of "stability, courage [and] self-esteem".

He said an addict's family and friends should "stop helping" and "let them hit rock bottom" - that was the only way an addict may choose to rebuild their life.