'Club Drug' May Fight Depression
Study Shows Ketamine May Provide Fast-Acting Depression Relief
WebMD News Archive
Aug. 7, 2006 -- Low doses of ketamine, a medication used as an anesthetic in
humans and animals, relieves depression in just two hours and the effect may
last as long as a week, new research shows.
Ketamine is also sometimes abused as a "club drug." Known in slang
as "special K," it can cause hallucinations and euphoria in higher
According to a study in the August issue of the Archives of General
Psychiatry, researchers tested 18 adult men and women diagnosed with
depression who had failed at least two antidepressant regimens. None of the
participants had a current substance abuse problem at the time of the
They were first tested with a one-time dose of intravenous ketamine or plain
saline. Then a week later, the ketamine group got a dose of saline, and the
saline group got a dose of ketamine.
Within an hour and a half after the injection, those who received the
ketamine had improvement of their depression -- with effects lasting for a
By contrast, current antidepressants, including the popular selective
serotonin reuptake inhibitors (SSRIs) -- such as Prozac and Paxil -- can take
weeks or months to kick in.
One day after the ketamine injection, 71% of participants responded with 50%
or greater improvement on a standard scale used to measure depression and 29%
met the criteria for remission. For 35%, the improved effects lasted through
the week, the study showed.
While the new results may not apply to all groups of depressed people,
"there is no treatment for depression that works this rapidly and
dramatically with a single administration," researcher Carlos Zarate Jr.,
MD, tells WebMD. Zarate is the chief of the mood disorders research unit at the
National Institute of Mental Health (NIMH) in Bethesda, Md.
Exactly how the anesthetic relieves depression is not fully understood, but
animal studies have suggested that blocking a brain chemical receptor called
the N-methyl-D-aspartate (NMDA) receptor can reduce depression-like behaviors.
Ketamine blocks the NMDA receptor.
In its simplest terms, ketamine hits the cascade of brain chemicals that
causes depression closer to home than available antidepressants, he says.
"If you had a leaky faucet, we start in the kitchen at the source of the
leak, [the NMDA receptor], while other antidepressants may begin at the water
processing plant, [the serotonin and other brain chemicals believed to play a
role in depression]," he explains. "We can localize it to right where
the leak is, so we don't have to be satisfied anymore with not getting results
for weeks to months," he says.
There are some safety concerns, especially because it has been taken in high
doses by substance abusers. "Ketamine should be studied in research
settings and not used in a clinical setting at this time," Zarate says.