(CNN Spanish) –– The autopsy of “Friends” star Matthew Perry concluded that the “acute effects of ketamine” and subsequent drowning were the cause of his death. The popular actor, who played Chandler Bing on the iconic series, was found dead and floating face down in the pool of his Malibu home on October 28. He was 54 years old.
The autopsy report released Friday by the Los Angeles Medical Examiner's Office found that Perry's blood contained ketamine, a substance known to treat depression and anxiety. But what exactly is this medication and how is it used?
Ketamine is a powerful drug used in hospitals primarily as an anesthetic, although studies have shown it also shows promise in treating severe depression, anxiety, and suicidal thoughts. It can also be used illegally as a club drug that produces a feeling of euphoria and dissociative effects.
The autopsy report detailed that ketamine is used as an anesthetic in medicine and surgery and is also known as a recreational drug, “primarily due to its 'dissociative' nature, which indicates a separation between mind and body.” It can also cause short-lived hallucinatory and psychedelic effects.”
But in Perry's case specifically, experts say that while the levels of ketamine in his body were very high, it's unclear whether they alone would have been fatal.
Dr. Ed Boyer, a professor of emergency medicine at The Ohio State University Wexner Medical Center, said, “Elevated levels of ketamine indicate high levels of use.”
According to the autopsy, Perry's last known treatment occurred a week and a half before his death, well beyond the duration of ketamine's effects in his body during treatment.
“Given that it has been at least a week since his last ketamine therapy, abuse, even recreational use, cannot be ruled out,” Boyer added.
Dr. Victor Weedn, a professor in George Washington University's Department of Forensic Sciences, said people can react differently to different amounts of ketamine and that it could be fatal because of its effects on breathing.
In 2019, the U.S. Food and Drug Administration (FDA) approved a close relative of ketamine called esketamine, which is used as a nasal spray to treat treatment-resistant depression.
Study results show that ketamine infusions improve symptoms of depression and anxiety
A study published in September 2022 found that people who were injected with intravenous ketamine at three private ketamine infusion clinics had a “significant improvement” in symptoms of depression, anxiety and suicidal ideation.
The study, published in the Journal of Clinical Psychiatry, adds to a growing body of research showing ketamine shows promise in treating these conditions. “It provides more real-world data, which is incredibly important” because it helps show its potential for a broader population, Dr. Gerard Sanacora, a professor of psychiatry at the Yale School of Medicine, told CNN at the time.
But the study left some critical gaps, including data on side effects and direct comparisons with other options, that made it difficult to draw a conclusion about how it should be used, he said.
Researchers analyzed data from 424 people with treatment-resistant depression who were seen between November 2017 and May 2021 at three ketamine infusion clinics in Virginia that specialize in people with suicidal thoughts, depression or anxiety. At each clinic visit, patients completed physical and mental health assessments.
Patients received six infusions over 21 days. Within six weeks of starting the infusions, the researchers say, half of the participants responded to treatment and 20% showed depressive symptoms in remission. After 10 infusions, response and remission rates were 72% and 38%, respectively.
The researchers also note that they have not systematically assessed treatment side effects or adverse events, but previous studies have not found any lasting or long-term side effects on memory or cognitive decline. The lack of information about side effects is “disappointing,” Sanacora said. Ketamine poses a “unique set of risks, both to the individual and to society,” including the potential for drug abuse and the unknown effects of frequent use, particularly at higher doses.
CNN's Katherine Dillinger, Josh Campbell, Cheri Mossburg and Deidre McPhillips contributed to this report.