Auckland teenager Rose started smoking synthetic cannabis with a friend two years ago just to "hang out".
"I had tried weed before, but I always felt guilty about that because it's illegal," she says.
"We tried that stuff (synthetic cannabis). We laughed and giggled and had a really great time."
Rose was 17. She had suffered from depression for about three years, used to self-harm, and realises now that she "kind of self-medicated with the synthetics — I found it helped with a lot of that".
But it quickly changed her character. "I was starting to have panic attacks about going to work.
"I ended up quitting my job. I started getting really temperamental. I would be hitting my boyfriend, which is not like me at all.
"One day I was in my room stoned on this stuff. My friends were going to come in. I jumped out my bedroom window and ran to a cliff just down the road. I was standing at the top of that cliff deciding what to do.
"I caused a major scene in a bar, like screaming, I looked like an absolute mental. But I never associated it with the synthetics because they would make me feel better."
She lost her boyfriend and her friends and was kicked out of her flat. She borrowed more than $1,000 from her dad and spent the lot on synthetics. She lost 20kg in three months. "All I did was smoke and sleep all day."
She finally quit when her doctor told her she was developing psychosis — literally losing contact with reality.
Rose is one of 29,256 people so far who "like" a Facebook page called "Ban Synthetic Cannabis NZ Wide", set up by 45-year-old mother Katie Bayliss in memory of her son Harley Pataka, 23, who committed suicide in Tauranga last month after smoking synthetic cannabis.
Many supporters will take to the streets in 23 towns from Whangarei to Invercargill today in a nationwide protest orchestrated by a Facebook event page set up by Tokoroa mother Julie King, "Aotearoa bans the sale and distribution of legal highs in our country".
Parliament passed a law last July which aimed to remove harmful synthetic drugs, requiring them to undergo clinical trials to prove they had no more than a "low risk" of harm.
Nine months later, 42 synthetic cannabis products with names such as "Choco Haze", "Tai High" and "Giggle" are still listed on the Health Ministry's website with interim licences for sale to anyone 18 or over.
A further 150 or so that had been on sale before last July were refused licences. The law also banned sales in dairies, petrol stations and liquor stores, reducing the number of outlets from 3,000-4,000 to 147, including 50 in Auckland.
But there are still shops from Kaitaia to Invercargill, even in small places such as Dargaville, Katikati and Edgecumbe. About 82 are specialist drug shops, judging by names such as "Heaven and Dreams" and "Cosmic Corner". Others are tobacconists, video stores, sex shops, tattooists and body piercers who have branched into synthetic cannabis.
Read: Government 'wimpish' over legal highs - Napier Mayor
Regulations governing the trials required under the new law are still being drafted, but Associate Health Minister Peter Dunne says products with interim licences will be able to stay on sale once the new regulations take effect in July or August as long as they submit plans for clinical trials. There will be no deadline on how long the trials take.
New Zealand is the only country in the world to adopt a pre-market clinical trial regime for recreational drugs, after abandoning what seemed a futile cat-and-mouse game of banning one drug only to find a slightly different version on sale the next week. Other countries are still applying what Rose and other protesters want — a straight ban, worded widely enough to cover all synthetic cannabis.
Massey University drug researcher Chris Wilkins says there is "enormous interest" overseas in New Zealand's approach. "People can see it's quite a radical experiment."
He says it could reduce harm if people move off more harmful illegal drugs on to less harmful legal ones. Or it could increase harm if it encourages law-abiding young people who shun illegal drugs to try synthetic cannabis, thinking it must be safe because it has been approved as "low risk".
The Health Ministry itself warns that "low risk" does not mean no risk.
"All medicines, even low-risk products, can cause harm and have the potential to cause severe and serious adverse events including death," it says on its website.
"These serious events can occur due to allergy, idiosyncratic response to the active ingredient, interaction with other medicines, overdose or misuse. The situation for psychoactive products will be no different."
Synthetic cannabis has only been widely marketed since 2008 but there are already reports in the medical literature of serious harm.
A 2012 German report, which the Health Ministry is using as the basis for New Zealand's risk assessment regime, looked at 29 patients who needed emergency treatment after using synthetic cannabis between 2008 and 2011 and found the most common symptoms were accelerated heartbeat, high blood pressure, nausea, blurred vision, hallucination and agitation.
Some suffered epileptic seizures. One developed acute psychosis. Three others in another study had heart attacks.
The authors found it was "probable" that the synthetic products induced stronger effects than natural cannabis because they were designed to fit more exactly with receptors in the brain. The NZ Health Ministry has accepted this finding, noting that "the prevalence of specific serious adverse events appears higher in the synthetic group of products".
Dr Susanna Every-Palmer, a Porirua forensic psychiatrist, reported in 2011 that nine out of 13 patients at her unit who used synthetic cannabis suffered psychotic relapses in the form of agitation and delusions.
Otago University psychologist Paul Glue reported that 13 per cent of admissions to Dunedin's acute psychiatric unit between January and April last year had taken K2, which was later banned. Thirteen of the 17 patients involved had longstanding mental illnesses, but the other four had no previous psychotic history before taking K2.
Professor Glue says longitudinal studies in NZ and overseas have shown that adolescents who started using natural cannabis at a young age were three to four times more likely than non-users to develop psychotic conditions such as schizophrenia.
"We just don't have the same amount of data for synthetics," he says.
"What you probably have is a number of individuals who already had a liability to develop psychosis, and other people who are lower down on the risk scale for whom, if certain things happen such as huge stress or they do a lot of drugs, they will also develop psychosis."
Mr Dunne says his office has rung around hospital emergency departments and found a drop in numbers presenting with synthetic cannabis-related problems since the law change last July.
"While I'm obviously concerned about anyone having an adverse reaction, the numbers are down," he says.
But Dr Fraser Todd of the National Addiction Centre in Christchurch, who also works in an adolescent mental health unit, says young people with drug-induced problems "present to psychiatric emergency, not emergency departments".
"We are getting a number of presentations of young people with agitation, aggression, paranoia, addiction and some withdrawal symptoms from synthetic cannabis," he says.
"We are getting significantly more over the past few weeks coming to us like this than from cannabis. It may be just a coincidence, or it may be that there is a batch with more potent stuff in it."
Yet Dr Todd is "in two minds" about whether to simply ban all synthetics, given the drug-makers' abilities to keep making new drugs. Also, the Health Ministry itself says that if alcohol was tested under the new regime it would pose "more than a low risk of harm", yet no one suggests banning alcohol.
"The most potent thing we can do is improve support for families and tackle poverty and those things that affect people when they are young," he says.
Synthetics left farmer thinking cows would kill him
A Waikato dairy farmer says smoking synthetic cannabis made him so paranoid that he thought his cows were out to kill him.
Scott Mackrell, 34, had just won his dream job managing a farm outside Hamilton two years ago when he started buying synthetic drugs instead of his usual marijuana — "because it was cheap".
He had smoked marijuana to relax since he was 15 but could take it or leave it.
"If I don't have any, I just think, 'Ho hum, no more weed'," he says.
But Mr Mackrell became totally hooked on the synthetics.
"Once I started, I found I couldn't stop," he says.
"I've woken up at every hour of the night wanting to smoke it. It was getting to the stage where at 7am I'd be at the dairy waiting for them to open."
He tried a variety of synthetics but his favourite was one called "SGT-25 or something like that" — possibly SGT-24, which is still listed on the Health Ministry's website as a legal drug.
Some of the drugs left Mr Mackrell paralysed, unable to reach his phone to call for help.
"I felt like I was checking out, I was literally dying," he says.
But their main effect was to feed a paranoia which made him think his boss and his girlfriend, and even his cows, were out to get him.
"I'd be milking the cows and flip out and think, 'I'm going to get killed, thinking all the cows are against me, they're going to trample me'," he says.
He drove long distances at 60km/h, afraid that other motorists would run him over. "I was so scared that at one stage I had to pull over and have a cry."
Mr Mackrell thought his girlfriend was cheating on him, and sat in the bushes outside her house for two hours every night watching who was coming and going.
"I had no control over what I was doing, even though my mind was asking me what I was doing," he says. "I just kept on going like I was a zombie."
Mr Mackrell finally got off the drugs three weeks ago through sheer willpower, and wants to warn the world about synthetics.
He now lives in Otorohanga and doesn't trust himself to drive through the nearest town that sells synthetics, Te Awamutu.
"It's still calling me," he says. "I'm still finding three weeks later that I'm not sleeping, I'm not eating ... I'm still hating myself for doing it and losing my job and my friends."
• NZ is the only nation permitting the sale of psychoactive substances if they are found in clinical trials to be "low risk".
• 42 substances have been given interim licences.
• All will have to reapply for licences under regulations starting in July/August.
• Interim licences will continue if owners can show plans for clinical trials.
• Nationwide protests in 23 centres today.