Special K could be the answer in the fight against depression, say scientists.
University of NSW researcher Prof Colleen Loo said the drug prompted improvements in people suffering clinical depression from within hours to a day later, News.com.au reported.
Given intravenously to people with moderate to severe clinical depression, the drug has been trialled in a handful of patients as part of the Australian-first study.
Researchers hope to recruit up to 40 patients as part of the ongoing trial, which is comparing people with depression given ketamine with those given a placebo.
Prof Loo said several international studies had produced similar instantaneous results.
Although the drug is approved for medical use in Australia for anaesthesia, sedation, and pain relief, the research is investigating the safety and effectiveness of the drug to treat depression before it can be widely used.
However, the research is still in its very early stages with fewer than 100 patients involved in placebo-controlled trials worldwide, Prof Loo said.
But if studies proved ketamine to be effective it could provide another avenue to treat depression sufferers within years, she said.
Prof Loo, from the university's School of Psychiatry and the Black Dog Institute, said ketamine worked in a completely different way in the brain than other treatments.
All other anti-depressant medications work on serotonin, noradrenaline and dopamine, but Ketamine works on a different neurotransmitter system, involving the chemical glutamate.
Prof Loo said studies in animals showed ketamine worked by promoting the regrowth and regeneration of brain cells.
"When people are depressed, cells in some parts of the brains ... become unhealthy and shrink. Ketamine reverses those kinds of changes. It's promoting the growth of new nerve projections and new synapses between nerve cells," she explained.
Participants in the trial are given up to six ketamine treatments intravenously, under strict medical supervision in hospital, a week apart.
The carefully-controlled doses are low - about one-tenth of the level used in anaesthesia.