Almost a year after the death of beloved Friends star Matthew Perry—and nine months after an autopsy concluded he had died from the acute effects of the anesthetic ketamine—several arrests have reportedly been made by Los Angeles authorities as part of their investigation into the source of the drug.

Perry’s personal assistant, two doctors, and two acquaintances were indicted and charged on Thursday with roles that included providing or administering the drug.

Jasveen Sangha of North Hollywood, known as the “Ketamine Queen,” and Salvador Plasencia, an urgent care physician, were charged with providing Perry’s assistant with the ketamine that led to the actor’s death. The assistant, Kenneth Iwamasa, according to reports of the indictment, injected Perry with the drug multiple times on the day he died. Roles of the others involved include assisting with the procurement of the drug and supplying the syringe used to inject the ketamine.

Drowning “in the heated end of his pool” also contributed to the 54-year-old actor’s accidental death—as did coronary artery disease and buprenorphine, used to treat opioid use disorder, according to reports by the Los Angeles County Department of Coroner via the Associated Press in 2023.

Perry was declared dead after being found unresponsive at his home in the Pacific Palisades area of Los Angeles on Oct. 28. While the actor had previously taken drugs, he had been “reportedly clean for 19 months,” according to the coroner’s report. He had reportedly received ketamine infusion therapy for depression and anxiety, the coroner wrote. But his last treatment was reported to have occurred a week and a half before his death.

Perry had reportedly played pickleball earlier in the day. His assistant, who said he found him face down in the pool after returning from running errands, told investigators that the actor hadn’t been sick, made any health complaints, or shown evidence of recent alcohol or drug use.

Ketamine, popularly known as the party drug Special K, has recently been hailed as a breakthrough treatment for major depression. But it is not without risks.

What is ketamine?

Ketamine is an anesthetic used by medical providers and veterinarians with some hallucinogenic effects, according to the U.S. Drug Enforcement Administration. A dissociative drug similar to psychedelics like nitrous oxide, it makes users feel detached from their pain, as well as their environment, distorting perception of sight and sound.

What is ketamine approved to treat?

It’s been approved by the U.S. Food and Drug Administration, in low doses, for use as a short-acting anesthetic in humans and animals, and as a nasal spray (esketamine) for treatment-resistant depression in conjunction with another oral antidepressant, according to the DEA. It’s a fast-acting antidepressant, used to bridge the gap while waiting for SSRIs to kick in, which can take weeks.

Can ketamine be used for depression?

Ketamine is only FDA-approved for use as a nasal spray in treatment-resistant depression. But it’s increasingly used “off label” for treating depression, suicidal ideation, and chronic pain, according to the U.S. National Institutes of Health’s National Library of Medicine. An increasing number of clinics offer infusions for the treatment of depressions. Patients are monitored during and after the infusion.

Is it possible to abuse ketamine?

It can be used illegally to get high—via an injectable, liquid mixed with other liquids, or a powder to be snorted, mixed in drinks, or smoked. On the street it’s sometimes known by the names Cat Tranquilizer, Cat Valium, Jet K, Kit Kat, Purple, Special K, Special La Coke, Super Acid, Super K, Horse Trank, and Vitamin K. An overdose can lead to loss of consciousness and dangerously slowed breathing, according to the DEA.

Users often partake of it with other drugs like Ecstasy (called “kitty flipping”), or cocaine, or sprinkle it on marijuana blunts, according to the Nemours Children’s Health system. It can also be smoked with tobacco.

The trip, called the “K hole,” usually lasts two hours or less. During this time, users may become nauseated, vomit, and/or have thinking and memory problems. High doses may cause movement issues, body numbness, and slowed breathing.

What are signs of a ketamine overdose?

Potential side effects of an overdose include respiratory failure and death.

Should ketamine and buprenorphine be used together?

Perry reportedly had buprenorphine—a medication approved by the FDA to treat opioid use disorder—in his system, in addition to ketamine. Using the two drugs together poses a “major” risk and can increase side effects like “dizziness, drowsiness, confusion, difficulty concentrating, excessive sedation, and respiratory depression,” according to Drugs.com. It advises users of both to “avoid activities requiring mental alertness such as driving, operating hazardous machinery, or engaging in potentially hazardous activities until you know how the medications affect you.”

The Associated Press contributed to this report.