The findings of a study published in JAMA Psychiatry have revealed that road testing for cannabis impairment may be putting up to 1.4m medical cannabis users at risk of unfair prosecution, according to a report by Volteface.
The double-blind, randomised, placebo-controlled clinical trial took place over two years between 2017 and 2019 at the Center for Medicinal Cannabis Research at the University of California. Participants were asked to consume a ‘cannabis cigarette’ then tasked with using a driving simulator. Further simulator tests were given at 30 minutes, 1.5, 3.5, and 4.5 hours after smoking. The results show that driving impairment for a regular cannabis consumer, when compared to the controlled placebo receiving group, was highest at 30 mins post-consumption.
After about 3.5 hours, participants in the cannabis-consuming group claimed that their perception of their driving skills had improved. However, the participants’ perceptions did not match the results of the driving simulator, as the results show that while recorded driving skill scores improved at 3.5 hours, levels of impairments did not totally diminish until roughly 4.5 hours after consumption.
The results of the study are a matter of concern to medicinal cannabis advocates, caregivers and policymakers, who say the UK’s roadside drug testing methods are wildly inaccurate. Current testing systems detect traces of cannabis for 30 hours after use, but according to the study, effects on driving wear off after 4.5 hours. As many patients use cannabis-based medicines to aid with sleep, the current detection window is of significant concern.
Campaigners are calling for the government to revise the current laws and bring them up to date with contemporary data. They say that medicinal patients must be able to use their prescribed medication in a responsible way without fear of prosecution.
Paul North, director of Volteface said, “This study shows that up and down the country medical cannabis patients who are perfectly able to drive are unnecessarily criminalised by the police due to inaccurate roadside testing. Now is the time for policymakers to update our policies, invest in new technology and protect the estimated 1.4 million medical cannabis patients in the UK.”
A prosecution for driving under the influence of cannabis will result in the loss of the driver’s license, which campaigners fear could lead to job loss, familiar breakdown and an increase in both mental and physical health problems.
Jonathan Nadler, CEO of the UK’s largest medicinal cannabis supplier LYPHE Group said: “This latest data reinforces our long-held belief that there needs to be a major change in the way we view and treat medicinal cannabis patients. They come to us suffering from painful and often debilitating conditions. The last thing they need is to fear being stopped at the roadside and arrested for accessing their medicine, which has now been legal in the UK for over three years. I hope this study helps lead to changes in our outdated system.”
Researchers also discovered that the levels of THC present in cannabis that is consumed prior to driving has no detectable impact on levels of driving impairment, which is another concern for campaigners. Patients are not able to measure their cannabis intake via the amount of THC alone, as this would not be an accurate way to determine if one was adhering to driving laws.
The team concluded, “The lack of relationship between blood THC concentration and driving performance raises questions about the validity of per se laws. When users control their own intake, one cannot infer the level of impairment based on the THC content of the product, the level of behavioural tolerance in the individual, or the blood THC concentration. Future research should address factors such as individual biologic differences, personal experience with cannabis, and cannabis administration methods in relation to driving impairment.”