According to researchers, the anesthetic and recreational drug ketamine could be effective in preventing suicide and lifting mood in people who are severely depressed in a way they describe as “game-changing.” They report the results of the pilot trial in The World Journal of Biological Psychiatry.

The results show that the drug known on the streets as ‘special K,’ was effective – at least temporarily – for most trial participants, who were all patients with major depressive disorder and who had exhausted all other treatments.

Lead author Colleen Loo is a professor at the University of New South Wales in Sydney, where she specializes in psychiatry and neurosciences. She describes the finding as a “game-changer in treating depression,” and says:

“The real advantage here is that the effect is almost instantaneous and that it appears to work on the majority of patients.”

Current drugs for depression can take up to 8 weeks to reach full effect. Also, it is not easy to match the right drug to the right patient, which has to be done by trial and error.

“This could be of real benefit if a patient is suicidal, as it could help yank them out of that really dark place,” says Prof. Loo, who also explains how ketamine works:

“Ketamine powerfully reverses structural changes in the brain that occur when someone is depressed. In a sense, the treatment is repairing or reversing those changes.”

The purpose of the pilot trial was to determine an appropriate dose rate for the drug. Previous studies have already established that ketamine potentially has impressive antidepressant effects, but nobody had yet determined how best to administer it or find the relationships between dose, antidepressant response and adverse effects.

Three out of four patients responded after single session

In their pilot dose-response trial of intravenous ketamine in treatment-resistant depression, carried out at Wesley Hospital in Sydney, the team found that three of the four participants showed an antidepressant response after a single session.

Although the trial was small, the finding is important, because as Prof. Loo explains, “These people are treatment resistant, so even a temporary reprieve is important.”

The trial also established that in some cases, less of the drug may be needed than the amounts used in other studies. Such a finding is important because less drug means less chance and severity of side-effects, such as altered perception and hallucinations.

The team also points out that an added advantage of ketamine is that it can be used with other antidepressants, which can be useful in maintaining sleep and appetite, for example.

Over the last 3 years, Prof. Loo’s team has been trialling ketamine on 19 patients – building on significant international research on the drug. They have also shown that you can safely administer ketamine under the skin’s fatty tissue.

The team now wants to do more work to add to these early results, depending on funding being available.

The trial was funded by a Research Fellowship Grant from the New South Wales Institute of Psychiatry.

Meanwhile, Medical News Today reported how researchers in the US believe they have achieved breakthroughs in treatments for depression. Investigators from the University of Texas Southwestern Medical Center uncovered an important mechanism by which the natural antidepressant hormone ghrelin works in the brain.

Written by Catharine Paddock PhD