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Medicinal cannabis plant

Driving in cannabis users

Exploring the effects of THC and CBD on driving

Does cannabidiol (CBD) modify the effects of tetrahydrocannabinol (THC) on driving? Does current roadside drug testing for cannabinoids accurately detect impairment?

Project overview

This is a randomised, double-blind and placebo-controlled crossover study that will investigate the effects of vaporised THC and CBD on driving.

The study will explore the idea that CBD content in cannabis plant material will modify the effects of THC on driving, and will investigate the link between concentrations of cannabinoids in blood and saliva, and driving ability. Participants of mixed gender aged 18-50 years will vaporise three varieties of cannabis over three research sessions in a counterbalanced order. In these sessions, participants will complete a driving simulation task as well as a series of cognitive tests. The three varieties of cannabis to be vaporised include a high THC/low CBD strain, a high THC/high CBD strain, and a placebo strain.

Drug testing of saliva and blood will follow current police procedures and a secondary aim of the study is to examine the relationship between positive results on these tests and actual driving impairment, which is currently a very controversial topic in the community and in legal circles.

This trial is no longer recruiting participants.

Thomas Arkell
Professor Nick Lintzeris
Associate Professor David Allsop
Paul Haber
Professor Iain McGregor

Jordyn Stuart
Chris Irwin

The Lambert Initiative

Experimental human psychopharmacology, clinical and analytical chemistry.

The Lambert Initiative.

Set up for this trial is in the final stages. Recruitment is anticipated to commence in June and July 2017.

Watch this space.