Matthew Perry died from the acute effects of ketamine, the Los Angeles County Medical Examiner revealed in an autopsy report released Friday. Contributing factors in the Friends star’s death, which has been ruled an accident, include drowning, coronary artery disease, and the effects of a drug, buprenorphine, used to treat opioid use disorder. 

Perry, who struggled for years with drug and alcohol use, was found unresponsive in a hot tub at his Los Angeles home in the afternoon on October 28. He was 54 at the time of his death. An autopsy was completed the following day but remained inconclusive until the results of a toxicology report were received. 

The actor was public about his addiction to drugs and alcohol, writing in his 2022 memoir, Friends, Lovers, and the Big Terrible Thing, that he almost died at the age of 49 after his colon burst from his excessive opioid use. Perry spent around $9 million trying to get sober. In an interview with People to promote his book, he said, “I had to wait until I was pretty safely sober—and away from the active disease of alcoholism and addiction—to write it all down. And the main thing was, I was pretty certain that it would help people.”

Ketamine is an anesthetic that can cause a dissociative state and can be used to treat depression and anxiety. According to the autopsy report, Perry had been receiving ketamine infusion therapy. His most recent therapy took place a week and a half before he died, but the medical examiner said the method of ketamine intake could not be determined because the ketamine in his system could not have been from that session since the drug’s half-life, the time it takes for the drug’s concentration in the body to be reduced by half, is just three to four hours. 

Perry, who was 25 when Friends premiered, also starred in the short-lived television series Studio 60 on the Sunset Strip, along with movies including Fools Rush In and The Whole Nine Yards. After his death, his Friends costars released a joint statement to People. “We are all so utterly devastated by the loss of Matthew,” they said. “We were more than just cast mates. We are a family.” Just last week, Jennifer Aniston told Variety that she had texted with him the morning of his death. “He was not in pain. He wasn’t struggling. He was happy,” she said.