One in every eight patients admitted to an acute psychiatric unit had been using the synthetic cannabis K2, an audit published today has found.
Researchers from Dunedin Hospital and Otago University checked records at an acute ward in the city from January 1 to mid-April and found 13 per cent of patients had said they were using K2.
The researchers say in today's NZ Medical Journal that their findings suggest synthetic cannabis can trigger psychosis both in those with no history of the mental disorder and in those who have had previous episodes.
"We also identified high rates of suicidal thinking and one instance of homicidal ideation [thinking about killing someone else] in this case series."
The patients' other symptoms included paranoia, disordered thinking, disorganised behaviour, anxiety and depression.
The patients' average age was 26.
The kind of study done means it "cannot establish rates of psychosis or mood disturbance caused by K2. Use of K2 was established by self-report, and thus its role in hospitalisation could be an under-estimate".
The findings indicated there was "substantial risk associated with use of synthetic cannabinoids", say the researchers, including Dr Leo Schep, a toxicologist at the university's National Poisons Centre.
The Government banned K2 last month, but drug manufacturers tweaked the composition with a "new" substance that avoids the ban.
The Psychoactive Substances Bill, now before the House, is expected to come into effect next month. It is proposed that dairies, service stations and grocery stores will be banned from selling synthetic cannabis and other legal highs. All other shopkeepers will need a licence to sell the drugs.
The legislation will require drug manufacturers to pay for clinical trials to prove their products are low-risk.
The symptoms reported by the K2 users included:
• Psychosis, including paranoia, disorganised behaviour and disordered thinking.
•Anxiety, depressed mood.
•Thinking intensely about suicide.
•Thinking about killing someone else.