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Cannabis health information labels: why it’s time to have mandatory warnings as part of any legal cannabis market

Jar of cannabis on a table

Prof. Adam Winstock – Global Drug Survey 2019

As the tide of cannabis regulatory reform wafts through North America and beyond, it strikes me that the cannabis legalisation lobby started from a strong position. The weight of evidence and cogent arguments at their disposal to counter the totally unhelpful criminalisation of cannabis users was enormous. The economic potential of legalisation and the benefits of not ruining lives with a pointless criminal record were pretty impressive. I also assume health harms and benefits were scrutinised. Experts would have been called in to give evidence, legal submissions made, often I guess comparing the health risks of cannabis to those of alcohol and tobacco. They will have stressed the potential medical benefits. They probably did not shout too loudly about the 10%+ of people who use cannabis who are dependent, that cannabis is a gateway to tobacco, the potential harms on developing young brains and exacerbating mental illness or effects on motivation or relationships of heavy use. I am sure these concerns were raised by evaluating committees. Perhaps advocates responded that a regulated market offered potential solutions to some of these issues not available when the drug is illegal. I don’t know.

The 6 cannabis labels evaluated by Global Drug Survey (n>55,000)


But I also suspect, that groups looking at the profit just within their reach were keen to portray cannabis as a very different sort of drug to alcohol and tobacco for loads of other reasons as well. And it seems that many governments (Canada aside) have accepted these differences and gone ahead with the legalisation of weed without mandatory health warnings or guidelines on lower risk use. That is a shame indeed, because a regulated drug market is a game changer. It allows governments to stop defining people by the drug they use, instead treating people as adults who are interested in their own health and wellbeing. A legal market allows for honest conversations about drugs that a zero-tolerance criminalised market does not.

Global Drug Survey is committed to helping people use drugs more safely regardless of the legal status of the drug. As part of GDS2019 we conducted the first ever international evaluation of cannabis labels containing information about health and ‘side effects’ related to the use of THC-containing cannabis. We adapted 4 health messages developed by the Canadian Government and added 2 messages on side effects based on common reasons that prompted people to quit (findings from GDS2018); effects on memory and motivation. For each label we asked do you believe the message, is the information new and would it change your behaviour?

People who use cannabis need to be informed and engaged.

Our study of over 55,000 current cannabis users suggests that the overwhelming majority of consumers would be happy to see such messages displayed on cannabis products (only 15% were opposed to the idea). The findings also suggest that as with alcohol, labels can be an effective way to raise awareness and encourage positive changes in behaviour. Although many cannabis users appear well informed about potential health harms over one quarter reported that that the information provided within the messages highlighting risks of dependence (1 in 10) and harms of cannabis smoke were new to the them. Over 75% believed the information contained on the labels regarding adolescent use, driving risks and cannabis smoke harms as well as the impact of cannabis use on memory and motivation. That only 65% believed the risk of dependence is probably rather convenient at the moment for the industry. ‘May cause dependence’ is not a good marketing label for any drug, but it’s one that needs to be talked about especially given that the majority of profits will be made from the minority of dependent users. The finding that the label highlighting the risks associated with ‘driving when stoned’ would get 50% thinking about not driving when stoned is also important since it’s unlikely that roadside drug testing alone will be sufficient to deter the behaviour. What will be needed is a change in acceptable norms; people don’t want to have an accident and don’t want to harm others. Raising concerns that are familiar to people as we did with our two ‘side effects labels’ on memory and motivation offer an alternative approach and one that may have merit, with over 30% reporting these would get people thinking about using less, significantly more than the percent indicating they may use less /not smoke following warnings on the risks of smoking, use under the age of 21 years and dependence.

The bottom line is this – if you are going to profit from selling cannabis (whether you are the government or a corporate entity) treat your customers with honesty and respect. Be open and transparent about harms. Provide advice and support to help them use cannabis in ways that add to their health and wellbeing not detract it. Being honest is not only the best drug policy but I also think it will the best way for private companies profiting from cannabis to interact with their customers and be viewed in a positive light. In my opinion it is inconceivable that any government that chose to regulate the cannabis market did not insist that all products carried health advice labels and links to free harm reduction / self-assessment tools such as those developed by GDS ( and

People who use cannabis are not daft. They want to be informed. I think people will respect producers and distributors all the more for it.

Cannabis companies are in their infancy – now is the time to help them grow into responsible adult corporations and a bit of smart of government regulation (like good parenting) may help quite a bit.

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