Russell Brand said he turned to drink and drugs as a youngster because he felt "lonely and sad" and that addressing the underlying issues for young people was more important than "moralising".
The comedian spoke as he backed an initiative by Amy Winehouse's father to tackle young people's drug and drink problems that "does not moralise" and does not tell children not to take drugs.
The Amy Winehouse Resilience Programme will be rolled out to 50 secondary schools across England and will provide a free confidential phone and online service for young people, supported by Childline.
It will also use recovering addicts to tell their stories in schools, rather than medical workers, police or teachers.
Russell, who stars in Get Him To The Greek, is now clean of drugs and alcohol, and threw his backing behind the programme.
"When you are talking to young people about drugs and alcohol, what's important is not to moralise about it or say 'don't do drugs' or futile, impotent messages that don't reach young people," he said.
"I think that it's important to address why people drink or take drugs in the first place, whether they are young or old. I remember when I was a kid the reason drugs first became attractive to me was because I felt kind of lonely and felt sad.
"What's important to me is the emotional and spiritual issues that underlie drug use in schools and in communities.
"I think if people have a facility and a system to address those emotional difficulties, then the patterns around their drug use, alcoholism also, will change."
Behind the programme is Mitch Winehouse, the late singer's father, who said he learned that his approach with daughter Amy, who died aged 27 in July 2011 from accidental alcohol poisoning, would "never work" for young people.