Synthetic cannabinoids have led to the deaths of about 80 New Zealanders in less than two years - and researchers want to find out why.
Otago University head pharmacology and toxicology Michelle Glass has recently been awarded funding from the Health Research Council to find out why synthetics are so dangerous and how to treat users at hospital emergency departments.
Prof Glass said synthetics had caused more deaths in New Zealand than in many other parts of the world.
"We're really just getting started on trying to understand where the massive toxicity is coming from, why people are dying from this.
"We've had synthetics on the market since about 2008, but the deaths are becoming more and more common.
"We know there are different chemicals coming out all the time, but I think the ones coming out right now are probably inherently more dangerous than the earlier ones."
Synthetic cannabinoids are mostly made in China by people who have some knowledge of chemistry. They are imported into New Zealand as a white powder that is difficult for law enforcement agencies to pick up, partly because there are more than 250 forms of the drug.
Drug importers in New Zealand mix the powder with solvents before spraying it on any kind of dried plant, so that it resembles dried cannabis plant material.
Prof Glass has been studying both natural and synthetic cannabinoids for almost 25 years and said the
drugs were vastly different.
"Cannabis has this perception of being safe, whereas the synthetics are clearly not safe.
"People are thinking it's just another kind of cannabis but it's not; it's a chemical made in a lab sprayed onto plant material."
The harm caused by synthetic cannabinoids could be related to the extremely high potency of the drugs, Prof Glass said.
"It's a completely uncontrolled, unregulated product obviously.
"There's no dose control. People could be getting a much higher dose than they need to get high. That could be what's driving the toxicity."
Contaminants in some batches could also be responsible for harmful health impacts and deaths, she said.
The research will also look at ways to treat people who arrive at hospital emergency departments suffering from synthetic cannabinoids.
This could include using medicines that block cannabinoid receptors in the brain to reduce the effects of the drugs, she said.
At present, most drug tests cannot detect synthetic drugs, so it can be difficult for hospital staff to know what people have taken.
While some have argued the illegality of cannabis had increased the use of the far more dangerous synthetic cannabinoids, Prof Glass said synthetics were cheaper and still used in countries where cannabis was legal.
Prof Glass said synthetics were the fastest growing recreational drug.