A study conducted in Australia to investigate the effects of THC on driving abilities for medicinal cannabis patients has produced some intriguing results. However, they should be taken with caution.
Researchers from the University of Queensland and University of the Sunshine Coast conducted a study that involved 41 participants and validated video tests. The participants underwent two tests (baseline, and after consumption), about one week apart.
Participants were evaluated on:
- Performance of Hazard Perception Skill.
- Driving-related risk-taking behaviours.
- Performance on self-perceived hazards perception skills.
- Driving skills, safety and self-perceptions.
Prior the post-consumption session, participants consumed a mean of 10.80 mg tetrahydrocannabinol (THC)Â and a mean of 16.05 mg cannabidiol (CBD).
Researchers discovered that performance in hazard perceptual skills was not affected by THC consumption. However, the perception of performance among participants did. However, they were still unable to self-assess accurately their performance.
In addition, the study found that medicinal cannabis users engaged in compensatory behaviors; they reduced their speed after THC consumption and increased their following distance. However, the gap acceptance behaviour (i.e. a space in which participants were willing to move out of traffic) did not change.
This is not a reason to encourage driving while intoxicated.
Researchers concluded:
As the use of medical cannabis grows in Australia and around the world, it is important to develop a complete understanding of THC’s effects both on objective driving performance and perception of that driving. This will help guide the future of road safety legislation.
Study has been published Journal of Pharmapsychology
THC is an issue that has sparked a lot of debate in Australia. The driving of any level of THC detected in blood is illegal, and it can even lead to the loss of a licence. THC remains detectable in the bloodstream for weeks, even after it has been consumed. Medical cannabis usage is essentially a self-imposed prohibition to avoid prosecution.
Another study by the same research group looked at the acute effects of medically prescribed oral and vaporised delta-9-tetrahydrocannabinol on cognitive functions important for driving.