New research has finally answered the question of exactly how long cannabis users are likely to be impaired by the substance and, in turn, how long they should wait before getting behind the wheel.
Unlike alcohol, which is easily measured as a percentage of alcohol in your blood, drug tests on the road simply measure whether or not there is any cannabis in your system. Unfortunately, this means the weed you (legally, only in the ACT, of course) smoked on the weekend could still present on a drug test long after it actually impairs your driving.
Obviously, this is a huge issue as the world (and Australia) moves towards recreational cannabis legalisation because our drug-driving laws are outdated, to say the least.
Researchers from the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney analysed 80 scientific studies on THC impairment in humans. According to their study, users were only impaired for 3-10 hours after taking moderate to high doses of THC.
According to the study, the level and duration of impairment depended on the frequency and dosage of THC. Additionally, impairment was impacted by the method of intoxication (orally or via inhalation) and other factors.
The researchers found that impairment could last a maximum of 10 hours – in the case of orally ingested (edibles) high-dose THC products.
“Our analysis indicates that impairment may last up to 10 hours if high doses of THC are consumed orally,” the study’s lead researcher Danielle McCartney told the ABC.
However, it appears the effect on the body is shorter for low doses consumed via smoking or vaping.
“A more typical duration of impairment, however, is four hours, when lower doses of THC are consumed via smoking or vaporisation and simpler tasks are undertaken.”
Interestingly, the study also found that regular cannabis users were, on average, less affected by the THC. Although this isn’t an excuse to get behind the wheel under the influence.
As for impairment while driving or doing other complex tasks, McCartney concluded that people could be compared for six to seven hours after inhaling moderate to high doses of THC.
However, remnants of the drug can be detected in your body for weeks after you last consumed cannabis, which means you could be up for some hefty fines and potential loss of license even if the drug is no longer posing any real threat to your driving or comprehension ability.
This is what McCartney hopes to change with her research.
“Our evidence should hopefully help people to make informed decisions and policymakers to make policies that are evidence-based and tell people how long they should wait before driving,” she said.
Assuming everyone reading this is a law-abiding citizen who doesn’t recreationally partake in the devil’s lettuce, it shouldn’t be an issue for most of us.
However, the current drug-driving laws in Australia are a huge issue for the 10,000+ medicinal cannabis patients in Australia, who are forced to make a choice between breaking the law or simply not driving for weeks after medicating.
“We’re having to say to people using medicinal cannabis: ‘Do you want to drive or do you want your pain relief, because you can’t do both,” Gino Vambaca, co-founder of Harm Reduction Australia told the ABC. “And that’s a horrible choice for them to have to make.”
As for the rest of us, the sooner we can find a logical way to differentiate between those who are legitimately driving under the influence, and those who simply have mild traces of the drug left in their system, the sooner we can (hopefully) see some real steps towards recreational legalisation in Australia.