New Zealand is one of the biggest cannabis users in the world. Photo/File
New Zealanders and Australians are the biggest cannabis users in the world.
Despite extensive research linking marijuana with slowed brain activity, memory loss and psychosis, we continue to light up.
Drug-driving statistics and scientific studies show the drug isn't doing our young people any favours, yet another growing season for New Zealand's most widely used illegal drug is well under way.
Police are appealing for help this summer, calling on trampers and campers to keep an eye out in case they stumble across plantations or growers tending their crops.
Tasman police Sergeant Rob Crawford says the cannabis season is usually accompanied by a spike in dishonesty offending, especially theft of electric fence units and tools from farm sheds.
"People going into the bush with gardening tools and water bottles is a bit of a give away."
Federated Farmers has issued a warning urging landowners to beware of "the perfect rural crime storm" this time of year brings.
Federated Farmers rural security spokeswoman Katie Milne says: "Illicit cannabis growers are at work, the rustlers are hitting farms and we expect equipment and even fuel theft. I have no doubt in some cases the three are interrelated." .
Cannabis growers focus on planting among crops in backcountry areas, making them visible only from the air.
National cannabis and crime operation Detective Senior Sergeant Scott McGill says growers are not only tending their crops on farmland but on Department of Conservation land too.
However, helicopters and planes are hugely successful at spotting cannabis plantations nestled in the bush, in annual spotting operations.
"We get between 100,000-120,000 plants a year, so we estimate that to be around 30-35 per cent of the cannabis grown nationally."
One plant is worth about $1000 on the street, he says.
Cannabis growing has been "fairly consistent" over the years and is not showing any signs of letting up.
The New Zealand cannabis market is estimated to be worth between $636 million and $1.27 billion a year, according to the Ministry of Social Development website.
Cannabis -
here and abroadAn Australian study published in British medical journal The Lancet in 2012 found cannabis use in New Zealand and Australia was the highest in the world, with 10-15 per cent of people aged 15-64 having smoked it in the previous year.
According to the World Health Organisation, about 147 million people use cannabis - about 2.5 per cent of the world's population.
And as the medicinal properties of the drug are being increasingly recognised, so are global movements towards legalisation.
According to the New Zealand Drug Foundation, scientific evidence suggests cannabis has therapeutic benefits in treating people with chronic pain, neurological disorders such as multiple sclerosis, nausea and HIV and cancer-induced weight loss.
Early this month, Colorado decriminalised the recreational use of cannabis, reigniting international debate about the drug's legal status.
Colorado retailers turned over up to $1.2 million selling the drug on the first day alone, and sales are expected to hit about $715 million by the end of the year.
Further south, Uruguay was the first country to legalise marijuana when it passed legislation in December, and Peru is expected to follow suit - though the drug is decriminalised in some other countries, notably Holland.
Back in New Zealand, the Class C drug is not likely to hit the shelves anytime soon.
Late last year, the New Zealand Drug Foundation's Cannabis and Health Symposium in Auckland heard how chronic cannabis use in early adolescence can make some people up to 11 times more likely to develop schizophrenia.
University of Wollongong's Associate Professor Nadia Solowij says memory, attention and higher cognitive functions all suffer long-term impacts from regular, heavy cannabis use.
"The longer you use cannabis and the more heavily you use cannabis, and the younger you are when you start using cannabis, the greater the changes that we see in the actual structure of the brain," Prof Solowij said.
"The adolescent brain is more sensitive to insult from drugs, and we've been finding that the younger people start using, the worse the cognitive impairment." A study of 1037 babies born in Dunedin between 1972-73 found an 8-point decline in the IQs of some early cannabis users, which was not recovered when cannabis use ceased.
Secondary Principals' Association president Tom Parsons says cannabis use among school students is dropping - though the number of pupils caught with the drug is on the rise.
"Because the data is so damning these days ... it affects your fertility, it affects your brain power, the carcinogens that lodge in your lungs ... it's hard to argue against [the evidence]."
Strangely, the number of kids caught with marijuana at school has actually risen, but that's thanks to heightened awareness and education among their peers, Mr Parsons says.
"We're catching more because the other kids are reporting it. There's no doubt in my mind there's a great decline and what the stats are showing us is we're more effective in taking preventative measures.
"The kids will tell us 'Jacinda's got dope at school' and we'll go and line up Jacinda and find out."
Declining rates of cannabis use are part of a general trend towards healthier lifestyles, as media keep pressing issues such as obesity, drug use and nutrition.
"Despite what other people say, we are becoming greener, and kids do take it on board."
Cannabis use in young people has major cognitive impacts, including psychosis and memory loss, he says.
"Kids come to school half asleep, they're still suffering the after-effects.
"There are no stoners in schools that are celebrated at prizegiving."
Drug driving
New Zealand Drug Foundation research found 58 per cent of Kiwis who drive after using cannabis think being stoned makes "no difference" to their driving ability.
According to the latest Drug Use in New Zealand Survey published in 2010, half of all drivers killed on our roads between 2004-2009 had alcohol and drugs in their systems when they crashed - and one-in-five of these drivers had used cannabis.
And getting high isn't just a risk to road users.
The pilot of the balloon that caught fire and crashed in Carterton in January 2012, killing all 11 on board, had cannabis in his system when he hit power lines.
A report on the accident said it was "highly likely" Lance Hopping had smoked cannabis shortly before the fatal flight and toxicology results found he had 2 micrograms of cannabis per litre of blood - consistent with smoking cannabis 4-6 hours earlier.
Cannabis crops - what to look out for
Waikato crime services coordinator Detective Senior Sergeant Nigel Keall says areas containing bush and scrub are often targeted by growers.
"The way criminals grow cannabis crops is no different to how fruit and vegetables are grown - seedlings are planted in spaces where there's sunlight, plants need regular watering and fertilising, and the crops need protection from pests provided by netting and fencing."
Growers regularly trespass on private land, damage legitimate crops and set traps to protect their plantations.
Red flags include discarded gardening packaging in unusual locations, people carrying gardening equipment in the bush and unexplained lights on farmland at night.
Growers can go to extreme lengths to protect their well-nurtured crops, even setting traps to fend off intruders, Mr Keall says.
In 2008 Hastings police officer Detective Constable Todd Lee was impaled on a "lethal" nail trap when he raided the home of a Napier cannabis grower.
A board trapped with upturned nails punctured the officer's foot when he jumped the fence, one nail going straight through his foot.
Farmers are also being urged to be vigilant for signs of illicit activity on their land. APNZ