Justin Bieber relied on drugs as an "escape" from his life in the spotlight.
The 25-year-old singer has admitted that he first tried marijuana when he was just 13, after rocketing to fame as a child when he was discovered on YouTube.
After becoming dependent on weed, Justin began to drink lean - a narcotic substance often called "purple drank" or "sizzurp" - as well as taking pills, doing Molly, and trying Shrooms.
Speaking about his addictions in an episode of his YouTube Premium documentary 'Justin Bieber: Seasons', he said: "It was just an escape for me. I was young. My experience was in front of cameras and I had a different level of exposure."
The 'Yummy' hitmaker made headlines as a teenager for getting into trouble with the law, and says he "valued the wrong things" in life because they were being "dangled" in front of him.
He added: "I started valuing the wrong things in this business because there were things dangling in front of me. The truth is, I never had the tools. My parents never gave me those tools to be a good team player."
Justin eventually decided to get sober because he was "dying", and said people aren't aware of how "serious" his addictions were.
He explained: "I was, like, dying. People don't know how serious it got It was legit, crazy scary.
"I basically said to myself, 'God, if you are real, you get me through this season of stopping these pills and stuff, and if you do, I'll do the rest of the work.' I never did the actual work. I got off the pills but never went to the root of everything so I just circled back around which most people do."
Justin's wife Hailey Bieber, 23, also appears in the documentary, and whilst she didn't meet the star until after he was sober, she can understand why he would turn to drugs to make himself "feel better".
She said: "I think when you take somebody very, very young and they get horrible, crazy crippling anxiety and it goes undiagnosed and you don't know what it is you are feeling, you start to self-medicate because it makes you feel better. Just helping not to feel anything."
Now, the 'Love Yourself' singer has an oxygen chamber in his house to help with his anxiety, and goes through nicotinamide adenine dinucleotide (NAD) IV treatment to help flush toxins out of his body.
Explaining the NAD process, Hailey told cameras: "For people who used to have a drug problem, when they get sober, the pleasure centres of their brain don't work the same. So what NAD does is actually helps to repair that part of that brain and it helps repair the pleasure centres to balance them back out."