Researchers have just completed a study on a new and experimental depression drug capable of alleviating symptoms of depression in individuals for whom other drugs have failed. Although the beneficial effects of the drug appear to have a short duration, they work rapidly at treating symptoms in comparison to other depression drugs, and exhibit fewer antidepressant side effects.

The drug, so far referred to as AZD6765, cleared up depression symptoms in subjects just 1.3 hours. Although the effects only lasted for around 30 minutes in some patients, others benefited as long as 2 days. The average participant had already tried seven different rounds of depression treatment involving various drugs and therapy methods, and almost half of them had already received shock therapy.

Are Faster-Acting Depression Drugs Necessary?

According to Dr. Carlos Zarate, one of the lead researchers behind the study conducted by the National Institute of Mental Health, there is an urgent need for faster-acting drugs designed to treat major depression. Drugs currently on the market can take many weeks, not hours, for their effects to kick in. This is far too long for a seriously depressed individual, especially if he or she is having suicidal thoughts as a component of their depression symptoms.

Aside from AZD6765, another drug known as ketamine is able to decrease symptoms of depression in a few hours, though ketamine is rarely prescribed because taking it can cause hallucinations along with other serious side effects. Ketamine, often referred to by its street name “Special K,” has a history of recreational use, and is sometimes prescribed as a sedative.

On the other hand, AZD6765 didn’t seem to produce any dangerous side effects at all. As a result, the researchers say that their ultimate goal is to produce a drug that works as quickly as AZD6765, and with a similarly low risk of side effects, but that lasts for a longer duration. According to Zarate, it’s possible that a larger dose of AZD6765 could be the answer, though this will depend on future research.

About the Study

In the study conducted by Zarate and his colleagues, half of subjects were given a placebo, while the other half were given AZD6765 intravenously. After being given either the drug or a placebo, the participants were asked to complete a survey designed to assess the severity of their depression symptoms. The subjects completed the same survey a few days later.

After a week had passed, the AZD6765 group was given the placebo, while the placebo group was given AZD6765, and the surveys were repeated.

Approximately 33% of the subjects reduced their depression symptoms by at least half as a result of taking AZD6765, while those who took a placebo only experienced a 15% drop in their depression symptoms.

Although AZD6765 was not found to produce any seriously dangerous antidepressant side effects, some of the side effects that did present themselves included difficulty concentrating, nausea and headache. According to Zarate, these side effects are negligible compared to those produced by ketamine.

How New Depression Drugs Differ From Older Ones

Typically, antidepressants treat depression by boosting levels of serotonin in the brain, which in turn improves mood. However, AZD6765 and ketamine work differently. Instead of boosting serotonin, they prevent glutamate, another chemical that influences mood, from binding to nerve cells.

AZD6765 produces very few major antidepressant side effects because it doesn’t prevent glutamate from binding to nerve cells as thoroughly as ketamine does. However, this same attribute may be the reason why the positive effects of AZD6765 don’t last as long as the benefits of ketamine.

In the future, researchers plan to study other new drugs that deal with glutamate binding, as well as existing drugs such as AZD6765 that could be produced as oral tablets in varying doses. It should be noted that AZD6765 is currently patented by pharmaceutical company AstraZeneca.

The Bottom Line

A new class of antidepressants that target the glutamate system as opposed to the serotonin system are currently being studied by researchers. One of these drugs, AZD6765, works much faster than current depression drugs and carries very few side effects. Unfortunately, its effects also wear off much more quickly than current drugs, and this is an area that the researchers hope to explore next.

The full text of the study is available online at the U.S. National Library of Medicine.