A low-cost version of ketamine could help treat people with severe depression.

In a new local clinical trial, more than one in five people saw complete remission of their symptoms after a month of twice-weekly injections of the ketamine. 

A third of people saw their symptoms improve by at least 50%.

The trial was a collaboration between six clinical mood disorder units in Australia and one in Aotearoa.

One hundred and seventy-nine people with treatment-resistant depression were given an injection of either a generic form of ketamine that’s already used as a drug for anaesthesia and sedation, or a placebo. 

The participants were asked to assess their mood at the end of the trial and again one month later.

As a double-blind trial, neither the participants nor the researchers knew which patients were getting the generic ketamine or the placebo. 

The placebo also caused sedation, so people didn’t know if they were receiving ketamine or not.  

Ketamine was clearly better than the placebo, lead researcher Professor Colleen Loo says.

Twenty percent of those who received ketamine said they no longer had clinical depression, compared to 2% of the placebo group.

“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 [a] placebo,” Loo says.

A more affordable treatment?

This new trial had a few important differences to previous research. 

Earlier studies just used saline as a placebo, meaning it was obvious who was receiving ketamine and who wasn’t. 

This trial also saw the ketamine delivered by injecting it directly into the skin rather than by drip, meaning it was much faster and less complex. 

But aside from the study’s positive results, Loo says one of the biggest benefits of using the generic ketamine is that it’s much cheaper than patented ketamine nasal sprays.

The difference in cost between the generic, low-cost ketamine and the nasal spray treatments can be around $850 to $900, Loo says.

The positive effects from both kinds of treatments can wear off after a few days to weeks, so more treatments could be needed - and Loo says the cost of these is prohibitive for many people.

An application to Medicare in Australia is now in place to fund this treatment, Loo says.

In New Zealand, low-cost ketamine can be used to treat depression as an off-label use (where a drug is used for an illness other than the one it’s been approved for). 

However this is currently only available at a few research clinics around the country. 

The researchers from this study are now looking at larger trials of generic ketamine over longer periods.

Where to get help:

• 1737: The nationwide, 24/7 mental health support line. Call or text 1737 to speak to a trained counsellor.
• Suicide Crisis Line: Free call 0508 TAUTOKO or 0508 828 865. Nationwide 24/7 support line operated by experienced counsellors with advanced suicide prevention training. 
• Youthline: Free call 0800 376 633, free text 234. Nationwide service focused on supporting young people.
• OUTLine NZ: Freephone 0800 OUTLINE (0800 688 5463). National service that helps LGBTIQ+ New Zealanders access support, information and a sense of community. 

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