Ketamine, the dance club drug known as ‘Special K’, acts like ‘magic’ to relieve depression, according to researchers who have investigated its effects.
The drug quickly induces the regeneration of synaptic connections between nerve cells in the brain, a study has shown.
Understanding the way the drug works could lead to better anti-depressant treatments, the scientists believe. At present around 40 per cent of depressed patients do not respond to medication.
Studies have shown that depressed patients who have resisted all other treatments improve within hours after receiving ketamine.
Ketamine, which has been found to relieve depression even among patients for whom other drugs don’t work, is quick acting and restored connections in brain cells of rats studied, according to a press release.
“It’s like a magic drug — one dose can work rapidly and last for seven to 10 days,” said Ronald Duman, professor of psychiatry and pharmacology at Yale. Duman is senior author of the study, which will be published Friday in the journal Science.
Ketamine
As long as a decade ago, Connecticut Mental Health Center researchers found the anti-depressant qualities of ketamine, which is used as a general anesthetic for children, the release said.
Ketamine relieves symptoms of depression in almost 70 percent of patients who resisted treatment with other anti-depressants, but its down side is that it must be given intravenously and can cause short-term psychotic symptoms in some patients, the release said. It has also been used as a recreational drug, known as “Special K” or sometimes just “K.”
Duman, George Aghajanian and others at Yale hope to make the drug safer and more easily administered by mapping its molecular action in the prefrontal cortex of rats. They found it acts on a pathway where synapses between neurons are formed.
“The pathway is the story,” Aghajanian said. “Understanding the mechanism underlying the antidepressant effect of ketamine will allow us to attack the problem at a variety of possible sites within that pathway.”
Ketamine is a drug used in human and veterinary medicine developed by Parke-Davis (today a part of Pfizer) in 1962. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist. At high, fully anesthetic level doses, ketamine has also been found to bind to opioid ? receptors and sigma receptors. Like other drugs of this class such as tiletamine and phencyclidine (PCP), it induces a state referred to as “dissociative anesthesia” and is used as a recreational drug.
Ketamine has a wide range of effects in humans, including analgesia, anesthesia, hallucinations, elevated blood pressure, and bronchodilation. Ketamine is primarily used for the induction and maintenance of general anesthesia, usually in combination with some sedative drug. Other uses include sedation in intensive care, analgesia (particularly in emergency medicine), and treatment of bronchospasm. It has been shown to be effective in treating depression in patients with bipolar disorder who have not responded to other anti-depressants. It is also a popular anesthetic in veterinary medicine.
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October 1st, 2010 at 5:35 am
New depression treatments favor a tailored approach and include recommendations for the use of shock therapy and other alternatives, including exercise when people fail to get relief from drugs.
The guidelines, issued on Friday by the American Psychiatric Association, are the first update on depression treatment in more than a decade.
“The five-year process of intense review, discussion and thoughtful revision-making has led us to today’s release of new guidelines that we believe will improve patient care,” Dr. Alan Gelenberg, an Arizona-based psychiatrist who led the group that drafted the guidelines, said in a statement.
“We are hopeful these guidelines will lead to improved lives for many patients.”
The panel searched more than 13,000 scientific articles published between 1999 and 2006 to craft the new guidelines.
Among the changes, the researchers recommend:
* Doctors should use rating scales to assess their patients’ conditions and tailor treatment according to the severity of symptoms. They can adjust various strategies such as medication, healthy behaviors, exercise and therapy.
* For people who repeatedly fail to benefit from drugs, the guidelines recommend use of electro-convulsive or so-called shock therapy, which has the most scientific data supporting its use.
* The recommendations also added newer treatments, including transcranial magnetic stimulation, which uses highly focused, pulsed magnetic fields to restore function to stimulate brain regions linked with depression.
Privately held Neurotonics Inc’s NeuroStar device was approved for this use by the U.S. Food and Drug Administration in 2008.
* Researchers also recommend use of vagus nerve stimulation, such as a device made by Cyberonics Inc, which delivers electrical stimulation to the vagus nerve, a major nerve linking the brain to internal organs.
* The guidelines also recommend regular exercise, which studies have shown can reduce depressive symptoms, especially in older adults or those with chronic medical problems.
* They recommend more frequent use of maintenance drug treatment, especially for people whose depression is likely to recur. This is especially important for people who have had three prior episodes of depression or chronic illness.
In a separate report, the U.S. Centers for Disease Control and Prevention said on Thursday that about 9 percent of U.S. adults surveyed in 2006 and 2008 had current symptoms of depression, including 3.4 percent who had symptoms of major depression, in which a person reports having five or more depressive symptoms for at least two weeks.
The survey included more than 235,000 people in 45 states, the District of Columbia and two U.S. territories.
Of these, only 4.8 percent of North Dakota residents were depressed, compared with 14.8 percent of those in Mississippi.
Overall, depression affects more than 13 million U.S. adults each year and costs billions of dollars to treat in costs for treatment, loss of productivity, workers compensation and death.
April 19th, 2011 at 8:43 pm
Anti-depressants may help spur the creation and survival of new brain cells after brain injury, researchers say.
Jason Huang and colleagues at the University of Rochester Medical Centre undertook the study after noticing that patients with brain injuries, who were prescribed anti-depressants, did better in unexpected ways than their other counterparts.
“We saw these patients improving in multiple ways – their depression was improved, but so were their memory and cognitive functioning,” said Huang, the Journal of Neurotrauma reports.
“We wanted to look at the issue more, so we went back to the laboratory to investigate it further,” said Huang, associate professor of neurosurgery at Highland Hospital, a Rochester affiliate.
Huang said many patients who have a traumatic brain injury also experience depression. By some estimates, half of such patients are depressed, according to a Rochester statement quoted in the journal.
Doctors are not sure whether the depression is a byproduct of the sudden, unfortunate change in circumstances that patients find themselves in, or whether it is a direct consequence of brain damage.
Previous research by other groups indicated that anti-depressants help generate new brain cells and keep them healthy in healthy animals.
That, together with the experience of his patients, led Huang to study the effects of the anti-depressant imipramine (Tofranil) on mice that had injuries to their brains.
Scientists found that imipramine boosted the number of neurons in the hippocampus, the part of the brain primarily responsible for memory.
By one measure, mice treated with imipramine had approximately 70 percent more neurons after four weeks than mice that did not receive the medication.
The team found that mice that had been treated with imipramine also had a better memory.
July 20th, 2011 at 2:10 pm
A new study has found that patients who use anti-depressants are much more likely to suffer relapses of major depression than those who use no medication at all.
Paul Andrews, McMaster evolutionary psychologist and lead author of the study, concluded that patients who have used anti-depressant medications could be nearly twice as susceptible to future episodes of major depression.
The meta-analysis suggests that people who have not been taking any medication are at a 25 per cent risk of relapse, compared to 42 per cent or higher for those who have taken and gone off an anti-depressant.
Anti-depressants interfere with the brain’s natural self-regulation of serotonin and other neurotransmitters, and that the brain can overcorrect once medication is suspended, triggering new depression, said Andrews.
“We found that the more these drugs affect serotonin and other neurotransmitters in your brain — and that’s what they’re supposed to do — the greater your risk of relapse once you stop taking them,” he stated.
The study was published in the journal Frontiers of Psychology.