Scientists measure how much weed Australians put in their joints

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How much weed is in that joint?  A team of Australian researchers has found that it is quite varied, which could have implications for public health policy.

‘The majority of Australian studies of cannabis use have assessed individual use by self-reported frequency of use and crude quantification as a proxy for cannabis exposure,’ the researchers write in their new paper, published in Drug and Alcohol Review. They use the example of ‘the number of joints or cones smoked per day’ on questionnaires.

‘These metrics do not account for variations in the quantity or potency of cannabis and may poorly estimate the potential harms of cannabis use.’

The researchers asked 31 people who had smoked weed within the last 30 days to roll their usual joints, spliffs or cones, except with oregano rather than cannabis.

The results were incredibly varied. In joints – that is a purely cannabis cigarette – the amount went from 0.10 – 1.25 grams. In spliffs – that’s cannabis and tobacco – the range was 0.12 to 1.21 grams.  In cones – that’s the section of a bong where the weed is packed – the range was 0.03 – 0.41 grams.

The researchers also point to previous research that between 81.6% and 85.7% of all cannabis in Australia is consumed by people who use it daily.

When the team asked the smokers to adjust the amount for a higher or lower potency, they did not do so in proportion to the THC concentration.

THC or Tetrahydrocannabinol is the compound in weed that makes you ‘high’. While they couldn’t measure THC concentration directly using oregano, when they told the smokers to roll as if the product was much stronger, the participants weren’t able to adjust enough to adequately reflect that change.

‘The variability in quantities prepared shows that the THC exposure from one joint, cone or spliff varies based on individual differences in the preparation of these most common routes of administration,’ the researchers write.

‘Importantly, it underscores the limitations of the current self-report metrics of only asking participants to report the number of joints or cones smoked per day in standard Australian national surveys.’