Examining the effects of cannabis on cognition and driving and blood THC levels

Following legalization, cannabis users have increased access to a variety of different types of cannabis. The use of cannabis edibles and vapes is on the rise while smoked cannabis is becoming less popular. Users report a preference for edibles and vapes because they believe that they are more discrete and safer (i.e. less chance of lung disease). However, there is little knowledge about the impact of these newer forms of cannabis on cognition and driving. In particular, there are few studies that directly compare the impact of different forms of cannabis on cognition and driving.

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Delta-9-tetrahydrocannabinol (THC) is the psychoactive component that is believed to be responsible for the intoxicating and behavioural activating properties of cannabis. Research shows that there is a dose-orderly relationship between blood THC and alterations in driving skills and cognitive function. However, the exact relationship between THC to cognition and driving remains elusive. Even though a relationship exists between blood THC and both cognition and driving, it is likely not linear or straightforward.

Understanding the relationship of blood THC to driving and cognition is important because it allows for the deterrence of driving after cannabis consumption. In Canada, legal limits of THC in blood vary from 2-5 ng/mL (there are stiffer penalties for higher concentrations). In this series of systematic reviews, I am delineating the differences in the impact of different routes of cannabis administration on cognition, driving and blood THC.

The team:
Patricia Di Ciano                       Amanda DeConinck
Sampson Zhao                         Siddhi Patel
Kruti Bhakta       Danial Behzad