The model was involved in a horrific hit-and-run accident when she was younger, which led to her getting hooked on the painkiller.
Speaking about her addiction to a UK magazine, she said: “If I was upset or in pain or in any type of emotional distress, I’d inject myself. I think that was a pattern that continued with drugs.”
The accident, which happened near her home in Bristol, resulted in Sophie having swelling of the brain and a severe dislocated foot.
Sophie developed gangrene and doctors had to cut away the decaying flesh, leaving her with a seven-inch gash.
She said: “I would have to scrape the wound clean every morning, which was agony. The only thing that helped was the morphine. I became dependent on it.”
The Celebrity Big Brother star says it was her addiction to morphine, a form of heroin, which led to her future addiction to cocaine, and saw her spend £10million on drugs.
Sophie became suicidal when the doctors failed to close the wounds with skin grafts but, eventually, herbal remedies helped her injury to heal.
She was then left with a morphine habit she was struggling to kick. “The withdrawal symptoms when I came off morphine were awful. I had cold sweats and was in agony.”
Sophie did manage to give up the morphine, only to swap it for cannabis and speed.
But it was her later addictions that cost her everything.
She said: “I didn’t like anything until I was 17 and I tried cocaine. That was my version of morphine and I was addicted to it for 10 years.”
After losing her friends, contact with her family and selling most of her possessions to fund her drug habit, Sophie finally went to rehab and she managed to quit for good in 2009.
“I’ve been clean for four years now and that’s my biggest achievement.”