Can’t Buy Me Love star Amanda Peterson died of acute morphine toxicity, the Weld County Coroner’s Office in Colorado said in a statement to PEOPLE.
According to a coroner’s report obtained by TMZ, Peterson, who was found dead July 5 inside her Greeley, Colorado, home, died of an accidental drug overdose. She reportedly had a deadly cocktail of prescription drugs in her system at the time of her death, including benzodizepines (anti-anxiety medication), opiates and phenothiazines (an anti-psychotic medication). Marijuana, which is legal in Colorado, was also found in her system.
The report also states the actress told someone a week before her death that she ingested morphine medication she received from friends and that she was self-medicating to manage pain. She was found to have six times the normal level of Gabapentin in her system.
The report also stated she died of a “morphine effect,” which triggers respiratory failure.
Peterson, who was 43 at the time of her death, rose to fame in the ’80s, making her debut in 1982’s Annie and later starring alongside Patrick Dempsey in the 1987 teen romantic comedy Can’t Buy Me Love.
The actress had her share of troubles in the past 15 years, and spent three months in jail in 2005. Her last arrest was in May 2012 for DUI and possession of narcotic equipment.
Shortly after her death, her mother, Sylvia Peterson, told Entertainment Tonight she was confident her daughter’s death was not related to substance abuse, saying she had been clean for some time: “This was not, in any way, a drug thing.”
Sylvia also told PEOPLE her daughter was in good spirits just before her death: “She was in bed, and she’d had a wonderful day, and we were planning on a dinner the next day. So it was just a very, very big surprise.”