Ketamine effectively treats severe depression in Australian clinical trial

Ketamine can effectively treat severe depression, according to a new study.

Ketamine can effectively treat severe depression, according to a new study.

Published Friday in the British Journal of Psychiatry, the study found that more than one in five patients with treatment-resistant depression saw symptoms disappear after receiving ketamine injections in a clinical trial, while one third reported their symptoms improved by at least 50 per cent.

"We found that in this trial, ketamine was clearly better than the placebo – with 20 per cent reporting they no longer had clinical depression compared with only two per cent in the placebo group," lead author Colleen Loo said in a news release. "This is a huge and very obvious difference and brings definitive evidence to the field which only had past smaller trials that compared ketamine with placebo."

Loo, a clinical psychiatrist and professor at Australia's University of New South Wales Sydney, calls ketamine a "powerful treatment" for depression.

"For people with treatment-resistant depression – so those who have not benefitted from different modes of talk-therapy, commonly prescribed antidepressants, or electroconvulsive therapy – 20 per cent remission is actually quite good," Loo said.

Primarily used as an anesthetic by veterinarians, ketamine is also used to a lesser extent in human medicine and as a recreational drug for its dissociative effects.

In the study, researchers tracked 179 patients with treatment-resistant depression. Participants were either given two weekly injections of ketamine or a placebo, and were then asked to assess their mood at the end of the month-long trial and again a month later. In the trial, a surgical sedative was chosen as the placebo instead of typical saline solution in order to simulate ketamine's effects.