It's no secret that drugs can ruin lives, but there is hope for those who become addicted, and Jason Isaacs' story is proof that their effects can be beaten.

The actor, who is known for playing Lucius Malfoy in the Harry Potter film series, opened up about his "decades-long love affair with drugs" in an interview with The Big Issue for its "Letter to My Younger Self" series.

"I've always had an addictive personality," Isaacs said. "By the age of 16, I'd already passed through drink and was getting started on a decades-long love affair with drugs."

Cast your mind back to the trailer for Harry Potter and the Philosopher's Stone:

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The actor explained that his struggle with addiction began when he was just 12 years old and got intoxicated for the first time.

"The barman, who we thought at the time was a hero and I now realize belonged in prison, sneaked us a full bottle of Southern Comfort," the actor recalled.

"We drank the entire thing in the toilet, then staggered out into the party, reeling around farcically. I vomited, fell on and pulled down a giant curtain, snogged a girl, god bless her … ran out into the street, vomited again, tripped, smashed my head open on the pavement and gushed blood all over my clothes."

He continued: "The next morning, I woke up with a splitting headache, stinking of puke, with a huge scab and the memory of having utterly shamed myself. All I could think was … 'I cannot (expletive) wait to do that again.' Why? I’ve no idea. Genes? Nurture? Star sign? I just know I chased the sheer ecstatic joy I felt that night for another 20 years with increasingly dire consequences."

Jason Isaacs. [[imagecaption|| Credit: PA Images]]

The actor explained that when he was at the lowest point of his addiction, he realized that he cared about drugs more than anyone else in his life.

"I remember there being a moment, not long before I got clean, when it suddenly occurred to me that if everybody I knew died, literally every single person, I probably wouldn't mind that much," he said.

"In fact, I might like it, because then it would be an excuse to sit in a room by myself and take drugs and everybody else would say, 'Well you know, fair enough, you heard what happened didn't you?'"

The now sober 57-year-old said he manages to "find simple happiness in simple things".

“I think what would surprise the 16-year-old me is that I'm OK," he added.

'Harry Potter' star Jason Isaacs reveals his 'decades-long love affair with drugs'