The amount of cannabis used in joints (purely cannabis), spliffs (cannabis and tobacco), and cones (pipes or bongs) in Australia varies a lot based on an individual’s own preparation techniques, according to Australian research.
In Australia, the most common route of administration is inhalation via joints (prepared by rolling a variable quantity of cannabis flower into a paper) and cones (the component of a bong in which an amount of cannabis flower is placed and smoked).
Typically, the amount of cannabis used in joints is larger than in cones, but this is largely disregarded in Australian surveys.
Cannabis also is commonly smoked together with tobacco in a ‘spliff’ which may have additional respiratory and addiction consequences, yet spliffs are rarely captured by cannabis metrics, despite the importance of understanding the adverse health outcomes resulting from co-use.
Previous research on the quantification of cannabis use had demonstrated that most people who use cannabis inaccurately estimate the quantity of cannabis used by common routes of administration and to test this, the study asked 31 people to roll joints, spliffs or pack cones using oregano instead of cannabis.
They found that the amount of oregano used in joints varied a lot, ranging from 0.04–0.41g in cones, 0.10–1.25g in spliffs, and 0.12–1.21g in joints, and when people were asked to repeat the task but this time imagining they were using higher or lower potency cannabis, they found the quantity of cannabis used varied with its perceived potency.
However, the adjustment was not proportional to the actual change in THC dose.
PhD student with the University of QLD and the National Centre for Youth Substance Use, Ms Danielle Dawson, explained that inconsistency in the amount of cannabis used based on potency and within different modes of administration may represent a problem for self-report metrics which ask participants to report cannabis use in joints.
“The current study is the first in over 10 years to explore the quantities of cannabis used in joints, cones and spliffs in Australia. We found substantial variations in the amount of cannabis used in joints, spliffs and cones in an Australian sample recruited from a Queensland university,” Ms Dawson said.
“The quantity of cannabis used in all modes of administration varied with the perceived potency of the cannabis.”
Participants rolling joints used less of higher potency cannabis (33% on average) and more when using low potency cannabis (26% on average). However, participants rolling spliffs added more low-potency cannabis (17% on average) but not less high-potency cannabis, while the converse was true for cones: there was less high-potency cannabis used (17% on average).
The analysis also demonstrated that people who reported daily cannabis use used over three times as many grams in a joint (M = 0.94, SE = 0.06, β = 0.66, p < 0.001) than people who used cannabis less than daily (M = 0.31, SE = 0.10) when controlling for age and gender which were not significantly associated with the amount used.
“Consistent with our predictions, people who reported daily cannabis use used a larger amount of average potency cannabis in joints than people who reported less frequent use,” Ms Dawson said.
“This is consistent with previous research showing that between 81.6% and 85.7% of all cannabis in Australia is consumed by people who use it daily and that people who use cannabis daily may develop a tolerance leading to higher consumption.
“Consequently, researchers should measure cannabis potency (i.e., objectively where possible) as well as quantity and frequency.”