Ketamine Eased Depression in Treatment-Resistant Bipolar
MONDAY, August 2 (HealthDay News) -- The anesthetic drug
ketamine helps ease depression in patients with treatment-resistant
bipolar disorder, a new study finds.
Depressive symptoms are a major part of bipolar disorder, which
affects about four percent of Americans at some point in their
lives. There are several approved treatments for bipolar disorder,
but some patients do not respond to these therapies.
Ketamine acts on the brain's glutamatergic system, which plays a
role in information processing and memory formation. Recent
research suggests that dysfunction in this brain system may
contribute to bipolar disorder, noted Dr. Nancy Diazgranados and
colleagues at the U.S. National Institute of Health.
Their study included 18 patients with bipolar depression that
didn't improve when treated with the medications lithium or
valproate. Two-thirds of the patients were on psychiatric
disability and nearly all of them were unemployed.
The patients received an intravenous infusion of either ketamine
or a placebo on two days two weeks apart. The order of the
infusions was randomly assigned.
The patients' depressive symptoms were assessed before each
injection and then 40, 80, 120 and 230 minutes, and one, two,
three, seven, 10 and 14 days afterward. Within 40 minutes of
receiving ketamine, the patients showed significant improvements in
depressive symptoms compared to those who received the placebo. The
improvements were most noticeable at day two and remained
significant through day three.
At some point during the study, 71 percent of patients responded
to ketamine and six percent responded to the placebo. No serious
side effects were reported during the trial.
The study, published in the August issue of the journal
Archives of General Psychiatry, provides evidence that the brain's glutamatergic system may play a role in bipolar disorder and that targeting it may lead to better treatments, the researchers wrote.
They also said that future research should explore how
ketamine's rapid effect on depression can be maintained over the
Although ketamine has been used off-label as an experimental
treatment for depression, it has not been approved by the U.S Food
and Drug Administration for that use, according to the U.S.
National Institutes of Health.
The U.S. National Institute of Mental Health has more about
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