Carrie Fisher’s death was caused by sleep apnea and other undetermined factors, the Los Angeles County Coroner’s Office revealed on Friday, according to multiple reports.
The coroner also said Fisher suffered from atherosclerotic heart disease and “drug use,” but no specifics were given. According to the Associated Press, the report stated Fisher had taken multiple drugs prior to her death.
“The manner of death has been ruled undetermined,” the report concluded.
In an exclusive statement to PEOPLE, Fisher’s only child, Billie Lourd, addressed the report.
“My mom battled drug addiction and mental illness her entire life. She ultimately died of it. She was purposefully open in all of her work about the social stigmas surrounding these diseases.
“She talked about the shame that torments people and their families confronted by these diseases. I know my Mom, she’d want her death to encourage people to be open about their struggles. Seek help, fight for government funding for mental health programs. Shame and those social stigmas are the enemies of progress to solutions and ultimately a cure. Love you Momby.”
The actress, best known as Star Wars‘ Princess Leia Organa, suffered a heart attack at the end of last year. She was flying from London to Los Angeles on Friday, Dec. 23, when she went into cardiac arrest. Paramedics removed her from the flight and rushed her to a nearby hospital, where she was treated for a heart attack. She later died in the hospital, just one day before her mother, Debbie Reynolds, passed away.
Lourd, 24, paid tribute to her mother and grandmother on Instagram days after their deaths.
“Receiving all of your prayers and kind words over the past week has given me strength during a time I thought strength could not exist,” Lourd wrote on Instagram Jan. 2, her first time commenting on their deaths. “There are no words to express how much I will miss my Abadaba and my one and only Momby. Your love and support means the world to me.”
Fisher had long been open about her struggle with bipolar disorder and substance abuse issues, starting at only age 13 when she began smoking marijuana.
She said she later dabbled in drugs like cocaine and LSD.
Fisher explored her issues with addiction in her 1987 best-selling, semi-autobiographical novel, Postcards from the Edge, which was later turned into a movie starring Meryl Streep.
“I couldn’t stop, or stay stopped. It was never my fantasy to have a drug problem,” she told PEOPLE in 1987. “I’d say, ‘Oh, f— it, I haven’t done anything for a couple of months, why not? Let’s celebrate not doing them by doing them.’ I got into trouble each time. I hated myself. I just beat myself up. It was very painful.”
She told PEOPLE in 2013, “The only lesson for me, or anybody, is that you have to get help. I’m not embarrassed.”
To seek support for anyone suffering from mental illness, contact the Jed Foundation.
— With Natalie Stone and Michael Miller