“Friends” star Matthew Perry died from the “acute effects” of the powerful sedative ketamine that, combined with other factors, caused the actor to lose consciousness and drown in his hot tub, according to an autopsy released on Friday.

The report from the Los Angeles County Medical Examiner came nearly seven weeks after Perry, 54, who publicly acknowledged decades of drug and alcohol abuse, was found by his live-in assistant floating face down and lifeless in the jacuzzi of his Los Angeles home.

Toxicology tests found ketamine, a short-acting anaesthetic with hallucinogenic properties, in Perry’s body at high levels well within the range typically associated with general anaesthesia used in monitored surgical care, the report said.

“Matthew Perry’s cause of death is determined to be from the acute effects of ketamine,” the autopsy concluded.

Coronary artery disease, the effects of the opioid-addiction medicine buprenorphine, also detected in his system, and drowning were listed as contributing factors in his death, which was ruled an accident.

The concentrations of ketamine in Perry’s body would have overstimulated his heart rate while depressing his breathing, likely leading him to lapse into unconsciousness before his face slipped below the water in the hot tub, the report said.

“The exact method of intake in Mr. Perry’s case is unknown,” the report said, adding that trace amounts of the drug showed up in his stomach. No recent needle marks were found on his body, it said.

Referred to as a “dissociative anesthetic hallucinogen” because it produces a feeling of detachment from pain, anxiety and the environment, ketamine can be injected, mixed with liquids, snorted as a powder, or smoked, according to the U.S. Drug Enforcement Administration.

Autopsy findings suggested Perry may have been self-medicating with ketamine between medically supervised treatments with the drug.

According to witness interviews cited in the report, Perry had been undergoing ketamine infusion therapy for depression and anxiety. But his last known treatment was a week and a half before his death, so the ketamine found in his system by medical examiners would have been introduced since that last infusion, the report said.

Perry’s Oct. 28 death came one year after the publication of his memoir, “Friends, Lovers, and the Big Terrible Thing,” which chronicled his decades-long bouts with addiction to prescription painkillers and alcohol, a struggle he said came close to ending his life more than once.

Perry, best known for his role as Chandler Bing on the 1990s hit television sitcom “Friends,” had been sober for 19 months with no known substance abuse relapses before his death, according to interviews cited in the autopsy.

Investigators found no alcohol, illicit drugs or drug paraphernalia at the scene of his death. Multiple nicotine vaping products and an inhaler were found in Perry’s living room. Injectables of the anti-diabetes medication tripeptide and nicotine lollipops were in the refrigerator.

The actor had stopped smoking two weeks earlier, had been prescribed Tamoxifen - a hormone regulator usually taken for breast cancer prevention - for weight loss, and was receiving testosterone shots, the report said.

Non-toxic levels of some prescription medications were detected in Perry’s body, but no traces of alcohol, cocaine, heroin or other illegal narcotics were found, the report said.

As was widely reported since, Perry had played pickleball hours before his death, and a witness who knew the actor told investigators he seemed to be in “good spirits” when she last spoke with him days earlier, the report said.