Pubdate: Fri, 20 Aug 2010
Source: Vancouver Sun (CN BC)
Copyright: 2010 The Vancouver Sun
Contact: http://www.canada.com/vancouversun/letters.html
Website: http://www.canada.com/vancouversun/
Details: http://www.mapinc.org/media/477
Author: Sharon Kirkey, Postmedia News
Bookmark: http://www.mapinc.org/find?158 (Club Drugs)

'MAGIC DRUG' GIVES HOPE TO BIPOLAR PATIENTS

Ketamine is mainly used as an anesthetic by vets but shows promise in 
treating depression

A new antidepressant being tested in Canada appears to do what no 
other drug can -- increase connections between brain cells within 
hours to swiftly improve symptoms.

The finding by Yale University researchers may explain how one dose 
of ketamine can reduce symptoms of depression within 40 minutes among 
the hardest-to-treat cases, and could help spur development of 
quick-acting antidepressants.

About 17 per cent of the Canadian population will experience major 
depression at some point in their lives.

Prozac-like drugs and other antidepressants take at least two weeks 
to produce an effect, and sometimes months for a full effect.

Even then, they work well in only about a third of patients.

The risk of suicide increases during those dangerous weeks or months 
of lag time.

"They start taking the drug, they're still depressed, they start to 
get a bit more energy, but their mood doesn't increase," said Dr. 
James Kennedy, director of the neuroscience research department at 
the Centre for Addiction and Mental Health in Toronto.

"The problem is keeping the patient on the medication and preventing 
them from using their new energy in a bad way to kill themselves.

"This finding might help to prevent what has been a major clinical problem."

Ketamine is a fast-acting liquid anesthetic used mainly by 
veterinarians; it's also used in human medicine, even in children, 
because it doesn't depress breathing.

It's also an illegal club drug, known as "special K" or "vitamin K."

The street version is usually sold in a powder form that can be 
snorted or mixed into drinks, or dissolved into a liquid and injected.

It acts like LSD, causing vivid hallucinations in users and a 
sensation of floating outside their bodies.

Earlier studies involving patients with "treatment-resistant" 
depression have found that those given a single dose of ketamine 
experience rapid and significant improvement in symptoms.

In a small study published earlier this month on patients with 
bipolar depression, 71 per cent of participants responded to ketamine 
versus six per cent who responded to placebo.

"It's like a magic drug -- one dose can work rapidly and last for 
seven to 10 days," Ronald Duman, professor of psychiatry and 
neurobiology at Yale, said in a media statement.

"If someone is extremely ill, and in many cases may be even suicidal, 
having a drug that works rapidly like this is just a tremendous 
resource to have," Duman said in an interview.

In experiments on rats, Duman's team found that ketamine acts on a 
pathway in the brain that forms new synaptic connections between neurons.

Synapses are like phone lines that allow neurons to talk to one 
another. The drug increased synaptic connections as quickly as two to 
four hours after treatment.

"The number of spines where the synapses occurs are increased by 
ketamine, in a very short time frame," Duman said.

"It's a pretty amazing effect when you think about it, that ketamine 
is able to produce this rapid increase in connectivity in the brain."

The drug also repaired connections between neurons damaged by chronic 
stress. Studies have shown that neurons can atrophy, or shrink, in 
response to chronic stress. Duman said ketamine may be able to 
reverse the effects of stress on the brain.

The goal now is to identify ketamine-like drugs that can have the 
same effect on the brain that can be administered more easily and 
don't have the potential for abuse. The Yale team is now testing 
several compounds.

However, "ketamine could be, and probably will be used until 
something better is available," said Duman, whose team's work is 
published this week in the journal Science.

Dr. Pierre Blier, Canada Research Chair in Psychopharmacology at the 
Royal Ottawa Mental Health Centre, has started using ketamine on 
selected patients.

"In the first 40 minutes, (patients) may have a spacey feeling, 
people may feel a bit disconnected from their surroundings, but they 
don't get frank hallucinations or anything like that, because it's a 
low dose," said Blier, director of mood disorders research at the 
Institute of Mental Health Research.

"Imagine someone who is in the ER (emergency department) and is 
highly suicidal. It would be a way to decrease the suicidal risk."

Ketamine's effects last only a week or two.

Blier said the majority of people relapse within two weeks.

Blier said the Yale research is "very encouraging", but that other 
brain pathways are likely involved in the action of ketamine.

However, "it's a really promising avenue, because even though 
ketamine may not be the long-term solution, we can develop drugs that 
would have the same biological effects."
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MAP posted-by: Jay Bergstrom