Highest dose of CBD does not affect driving, research finds

Research from the University of Sydney has found that the highest daily medicinal dose of CBD has no impact on people’s driving or cognitive abilities.

New research published in the Journal of Psychopharmacology has found that even the highest medicinal dose of 1,500mg of CBD does not affect driving ability or cause impairment.

Unlike THC, a cannabis component that can induce sedation, euphoria and impairment, CBD does not appear to intoxicate people. Instead, it has been reported to have calming and pain relief effects.

Most countries allow people to drive while on CBD, however research into its impact on tasks like driving is lacking.

“Though CBD is generally considered ‘non-intoxicating’, its effects on safety-sensitive tasks are still being established,” said lead author Dr Danielle McCartney, from the University’s Lambert Initiative for Cannabinoid Therapeutics. “Our study is the first to confirm that, when consumed on its own, CBD is driver-safe.”

CBD use is increasing in western nations, with the Centre for Medicinal Cannabis estimating that six million people use the supplement in the UK. It is most commonly used for pain, sleep and anxiety.

The study involved 17 participants undertaking simulated driving tasks after consuming either a placebo or 15, 300 or 1500 mg of CBD in oil. These amounts represent frequently consumed dosages: up to 150mg/day over the counter; and up to 1500mg/day for conditions such as epilepsy, pain, sleep disorders and anxiety.

First, participants had to try to maintain a safe distance between themselves and a lead vehicle and then ‘drive’ along highways and rural roads. They completed the task between 45-75 minutes after taking their assigned treatment and then again after 3.5-4 hours to cover the range of plasma concentrations at different times. They repeated this under each of the four different treatments (placebo and three different doses).

The researchers measured participants’ control of the simulated car, tested by how much it weaved or drifted, as well as their cognitive function, subjective experiences and the CBD concentrations in their plasma. They concluded that no dose of CBD induced feelings of intoxication or appeared to impair either driving or cognitive performance.

“We do, however, caution that this study looked at CBD in isolation only and that drivers taking CBD with other medications should do so with care,” Dr McCartney said.

A 2020 study, also by the University of Sydney, found very low doses of vapourised (‘vaped’) CBD – a less common method of taking the drug – were also driver-safe.

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