There have been calls for legislation to be changed, with researchers saying it should focus on the time period where drivers are most at risk. Source: Freepik.
A study by The University of Sydney has revealed that THC affects drivers differently, citing that not all related skills are severely impaired.
Undertaken by the Lambert Initiative for Cannabinoid Therapeutics, research showed that several driving skills such as car following, speed and speed variability as well as sensory discrimination and time perception were not affected by THC. 10 years’ worth of data from 80 scientific publications on were studied in detail to see what the overall consensus was.
Some findings did conclude that THC had an effect on “demanding or complex skills” when it came to driving performance, such as lateral control, staying in a lane without weaving, and reaction time. It was also noted that affects were less on those who frequently use cannabis, than those who don’t.
Researchers explained why this might happen.
“One possibility is the downregulation of cannabinoid receptors, meaning that over time after frequent cannabis use, the number of receptors on the surface of target cells may decrease, leading to reduced sensitivity to cannabinoids.
“Other possibilities that could explain these differences are receptor internalization (where cannabinoid receptors are taken inside the cell’s membrane, so they are less available to bind to cannabinoids on the surface of the cell).”
Lead author of the paper Danielle McCartney said that impacts of THC depends on the way it’s taken, citing that recovery times would be different.
“The administration of cannabis (the way THC enters the body), makes a significant difference in how users are affected,” McCartney said.
“Orally ingested THC (in an oil, capsule, or spray) and inhaled THC (smoked or vaporized) have different pharmacokinetic profiles.”
Scientists discovered that driving-related skills often return to normal within five hours with all skills returned within seven hours after inhaling about 20 milligrams of THC. Recovery time was three to five hours for 10 milligrams.
McCartney called for legislation to be reviewed when it comes to cannabis and driving.
“The mismatch between the estimated length of impairment (3 to 10 hours) and the length of time THC can be detected in biological matrices (up to 7 days in blood and longer in extreme cases) would indicate that biomarker-based methods of identifying cannabis intoxicated drivers are ineffective.
“Detecting THC in a user’s system long after driving skills have recovered doesn’t provide useful information about who should or should not be on the road.
“Our legal frameworks need to focus on the period.”
