Pubdate: Tue, 08 Aug 2006
Source: BBC News (UK Web)
Copyright: 2006 BBC
Website: http://news.bbc.co.uk/
Bookmark: http://www.mapinc.org/rehab.htm (Treatment)

DRUG 'TREATS DEPRESSION IN HOURS'

An anaesthetic can treat depression within hours, US research suggests.

The study involving 17 patients found ketamine - used as an 
anaesthetic but also taken as a recreational drug - relieved symptoms 
of depression.

Most existing treatments for depression take weeks or even months to 
relieve people's symptoms.

But the team, writing in Archives of General Psychiatry, said 
ketamine would need to be altered so it lost its existing 
hallucinatory side-effects.

Scientists from the National Institute of Mental Health (NIMH) 
injected 17 patients with either a very low dose of ketamine or a 
placebo of saline solution.

The participants were all depression sufferers who had tried an 
average of six treatments that had failed.

The researchers then measured their levels of depression minutes, 
hours and days after the dose was given.

Lead researcher Dr Carlos Zarate Junior, head of the mood and anxiety 
disorders programme at NIMH, said: "Within 110 minutes, half of the 
patients given ketamine showed a 50% decrease in symptoms."

By the end of day one, he added, 71% had responded to the drug. And 
at this point the team found 29% of these patients were nearly symptom free.

The researchers also discovered one dose lasted for at least a week 
in more than one-third of the participants.

Brain pathways

Dr Thomas Insel, director of NIMH, commented: "To my knowledge, this 
is the first report of any medication or other treatment that results 
in such a pronounced, rapid, prolonged response with a single dose.

"These were very treatment-resistant patients."

Many antidepressants target levels of brain chemicals, such as 
serotonin and dopamine, and, over time, the accumulation of these 
chemicals can affect a patient's mood. But this can take several weeks.

But the team believes ketamine is having a faster effect because it 
is targeting a different brain-protein, called the NMDA receptor, 
which is thought to play a critical role in learning and memory.

The team says ketamine, in its current form, would not be appropriate 
for medication because of side-effects at higher doses, which include 
hallucinations and euphoria.

Dr Zarate said: "This study is a tool to help us understand what part 
of ketamine is causing this effect so we can refine and develop better drugs.

"We are also looking at ways that we could use ketamine maybe in 
lower doses or with drugs that block its perceptual effects so we 
could perhaps use it clinically."

Professor John Henry, a clinical toxicologist at St Mary's Hospital 
in London, said: "This is a very interesting piece of work, very 
neatly done, with promising results.

"More studies need to be done to see if ketamine would work over a 
longer period given in repeated doses.

"The benefit of having a fast-working drug would mean people could 
return to work quickly, and it could reduce risk of self-harm or 
suicide that could happen during the time-lag that occurs with other drugs."
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MAP posted-by: Beth Wehrman