A single dose of an anesthesia drug provided respite from depression for a small group of patients in whom other treatments had failed, report U.S. researchers.
The researchers however indicated that the drug, ketamine, is unlikely to be put to use in the treatment of depression because of potential side effects, which includes psychosis. But the finding does signal a new direction for future research related to depression.
Currently available antidepressants take a long time to work. Ketamine,the anaesthetic drug, is effective not only for its speed, but also because it focuses on a new system in the brain.
"It's novel because all antidepressants that are currently available work on neurotransmitters that are monoamines like dopamine and serotonin. That's the focus of the current antidepressant armamentarium," Dr. Richard A. Friedman, director of the psychopharmacology clinic at Cornell University's Medical Center in New York City said."Ketamine involves a particular system of the brain called glutamate. It's the main excitory neurotransmitter in the brain," he added.
Depression , a disabling condition, chronic in nature, affects almost 15 million Americans, that is, 7 percent of the adult U.S. population -- in any given year. 4 percent of these patients take their own lives, resulting in 30,000 suicides per year.
Unfortunately, 50% of patients with depression don't receive treatment and, of those who do, only 40% get the best. Some don't get better even with the best treatment.
This is one of the first studies to analyse the effect of ketamine on depression in humans, the result of which is published in the August issue of the Archives of General Psychiatry. It was observed that depression improved within a day in 71 percent of the participants who were treated with ketamine, 29 percent of whom became nearly symptom-free in a day.
Short-term side effects, including perception disturbances, usually disappeared before the antidepressant effect started to make an appearance. Participants were given a relatively low dose, so they were spared the more severe side effects.
Ketamine works by blocking the N-methyl-D-aspartic acid (NMDA) receptor, which receives signals for glutamate.
The researchers are now looking at other drugs to tackle depression.