Legalising cannabis doesn't make teens want to smoke it - study

New research finding legalising cannabis doesn't result in more teens taking up toking has been dismissed by opponents of the widely-used drug.

Researchers in the US looked at 25 years of survey data in 33 states, including 27 which have legalised medicinal use and seven where it's legal to smoke for fun. All-up 1.4 million high school students' responses were looked at.

According to the findings, published Tuesday (NZ time) in journal JAMA Pediatrics, there was no link between legalisation for medicinal or recreational purposes and increased rates of teenage cannabis use. In fact, they found the opposite.

"Recreational marijuana laws appear to be associated with a decrease in the odds of both measures of marijuana use, which may be because it is more difficult for teenagers to get marijuana if drug dealers are replaced by licensed dispensaries that require proof of age," the Montana State University researchers said in a statement.

The Drug Foundation's Ross Bell said the results weren't surprising.

"The research makes the important but very simple point that drug dealers don't check ID," he told Newshub. "To gain access to a cannabis retail store in North America, to get in the door, you have to show ID. I did a tour last year of three jurisdictions... and you literally could not get through the door unless you had valid ID. 

"In New Zealand, young New Zealanders are going to retail outlets run by organised crime - tinny houses don't check ID. They're more than happy to sell cannabis and any other drug to young New Zealanders." 

The Green Party drug reform spokesperson Chloe Swarbrick, said, "We've consistently seen, across jurisdictions that have moved to sensible legal regulation of cannabis, that we create a sense of order and control over what is chaos when left to prohibition.

"With education and meaningful regulation, we take the situation out of the shadows and into the light, where we’re able to effectively build greater community wellbeing and health."

Skepticism from opponents

But conservative lobby group Family First says the study has flaws - the Youth Risk Behavior Survey (YBRS), from which the researchers pulled their data, only covers teenagers who go to school.

"All YRBS data is also self-reported, and underreporting or overreporting of behaviours cannot be determined," said national director Bob McCoskrie, who also took aim at one of the groups which funded the study.

"The Koch Foundation is pro-cannabis law reform."

He said the latest study "goes against other governmental evidence showing higher usage rates in legalised states", citing data collected by the National Survey on Drug Use and Health (NSDUH) - an annual survey run by the US government. 

"Colorado, where recreational marijuana has been legal since 2012, has the highest rate of first-time marijuana use among youth," said McCoskrie.

Legalising cannabis doesn't make teens want to smoke it - study
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The NSDUH data shows use in states where it's legal is generally higher than where it isn't across all age groups, including youth. But states where cannabis was popular when illegal were arguably the most likely to vote for legalisation in the first place. 

The NSDUH data also shows that in Colorado - the first state to legalise cannabis - first-time use rates amongst 12- to 17-year-olds are in fact the highest in the country, as McCoskrie says.

But past data collected by the NSDUH also shows since 2012, usage rates amongst 12- to 17-year-olds in Colorado has fallen. In 2012 17.6 percent of 12- to 17-year-olds reported using cannabis in the previous year, and 10.47 percent in the previous month.

By 2017, those rates had fallen to 16.97 and 9.02 respectively - backing up what the latest study has found. Across the US, the data shows past-month use for teenagers falling from 9.82 percent to 6.46 percent, and past-year from 13.86 to 12.19. 

"Yes - overall use around the US is reducing in parts of that specific age group - but legalised states continue to buck the speed of that trend," McCoskrie replied.

"It simply confirms that New Zealand would do well to wait and watch. At the end of the day, it's a society-wide policy that will affect all age groups."

Legalising cannabis doesn't make teens want to smoke it - study
Photo credit: Getty Images

National drug reform spokesperson Paula Bennett echoed McCoskrie, saying flatlining use was not an argument in favour of legalisation.

"This doesn't align with the Government's intention of minimising harm, as drug use hasn't decreased but instead stayed the same," she told Newshub.

"There is also mixed evidence on how prevalent the black market still is. There are some places where the use of the black market has increased, especially when people can obtain a cheaper product with a higher potency."

She said more time was needed to evaluate the effects of legalisation in Colorado and Canada "so we can make the best-informed decision before we go ahead with legalising recreational marijuana".

Bennett in May declined invitations to debate Swarbrick on cannabis legislation, saying a "'for and against' argument at this time is not the best way for the public to get the best information".

NZ vs US legislation

Bell said any New Zealand legislation would be stricter than that in the US because advertising wouldn't be allowed.

"They've studied examples of legalisation that New Zealand wouldn't want to follow, and even bad examples, or examples which would be more liberal than we would want, still have these success stories like Colorado."

Bennett said even with liberal regimes, the US has problems with black market bud.

"Both California and Canada have legal, regulated markets for cannabis, however in both jurisdictions a thriving black market still exists due to high prices, high taxes, and in some places, limited legal access."

Legalising cannabis doesn't make teens want to smoke it - study
Photo credit: AM Show

Bell also took aim at Bennett's reluctance to embrace cannabis legalisation while alcohol remained on shop shelves.

"She isn't saying let's let organised crime manage alcohol - she's not saying that. She knows that with a harmful substance like alcohol, it's better to have it legal and regulated with taxation, marketing controls and age restrictions, limiting the potency of the product. 

"If she truly believed prohibition was successful for cannabis, then logically she should be making the same arguments for alcohol - and she's not. I think she knows that prohibition does not reduce the harm, and that regulation gives us a greater chance at managing any harms there might be."

Swarbrick said, "Under prohibition, Aotearoa New Zealand has had stubborn cannabis consumption rates of 11 percent of the population annually, and we know that a large majority of New Zealanders will have tried it by the time they're 21 – the majority coming into contact with it while at high school. Drug dealers don't check ID.

"Under legal regulation, we replace the black market with regulated providers who have a legal duty of care. With even better regulation than we've seen in other countries around the world, we would expect similar if not better results."

New Zealanders will get their say at the 2020 election, with a referendum on recreational cannabis expected to be on the ballot.