Many more Americans are turning to ketamine for kicks, a new study reports.

Recreational use of the anesthetic drug among U.S. adults increased 40% between 2021 and 2022, researchers say.

That follows a nearly 82% increase in ketamine use from 2015 to 2019, results show.

The more recent increase occurred mainly among young adults 26 to 34, as well as in people with a college degree, researchers found.

“These findings are consistent with other research indicating increased use among nightclub attendees in New York City along with increasing law enforcement seizures of illicit ketamine in the U.S.,” wrote the research team led by Dr. Kevin Yang, a third-year resident physician in psychiatry at the University of California-San Diego School of Medicine.

Ketamine — also known as “Special K” or Super K” — is typically used as an anesthetic for people and animals.

In 2019, the U.S. Food and Drug Administration (FDA) approved the use of a nasal spray ketamine derivative called esketamine (Spravato) to treat depression in adults, according to the National Institute on Drug Abuse (NIDA).

Ketamine can cause changes in how people perceive reality, the NIDA says. Users might feel like they are floating outside their bodies or dissolving into their environment.

“At higher doses, a person may experience extreme detachment from their body and reality, which is called being in a k-hole,” the NIDA’s website on ketamine says.

A ketamine overdose can cause potentially life-threatening slow and shallow breathing, particularly when combined with other drugs. Long-term use is linked to memory problems, depression and anxiety.

For the new study, researchers analyzed data gathered between 2015 and 2022 by an annual federal survey on drug use and health.

They found that the surge in ketamine use during the 2010’s was largely associated with people suffering depression. Adults with depression were 80% more likely to have used ketamine between 2015 and 2019, possibly self-medicating their mood disorder.

But the increase between 2021 and 2022 occurred only in people without depression, results show.

“These findings suggest a potential shift in the relationship between ketamine use and depression, such that recreational use became less associated with depression over time,” researchers wrote in study published recently in the Journal of Affective Disorders.

People with college degrees were more than twice as likely to have used ketamine during the latest surge, compared to those with a high school education or less, results show.

And young adults 26 to 34 were 66% more likely to have used ketamine than 18- to 25-year-olds, researchers found.

“In particular, ketamine use was highly associated with the use of other ‘club drugs,' such as ecstasy/MDMA, GHB, and cocaine,” researchers wrote. “These findings suggest that ketamine use often occurs in the context of poly-club-drug use.”

These shifts provide public health officials with clues for responding to increasing ketamine use.

“Prevention outreach should be expanded to settings like colleges where younger adults may be at heightened risk, providing education on the harms of polydrug use, particularly in combination with opioids,” the researchers concluded.