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The use of cannabis is on the rise in older adults. Coupled with the fact that the number of older drivers is increasing, this makes it more likely that there will be an increase in people over the age of 65 driving under the influence of cannabis. There is compelling evidence that cognitive and pharmacokinetic changes in older adults may make them more sensitive to the effects of cannabis, and that the effects of cannabis may be prolonged. Despite this, there are no controlled laboratory studies on cannabis-impaired driving in people over 65, and the published literature has focused primarily on the effects of cannabis within one hour of consumption. Thus, important questions remain about the safety of cannabis in older drivers. The purpose of the present study was to investigate the effects of cannabis on psychomotor (driving), subjective, physiological and cognitive outcomes. Participants were invited to the lab where they smoked their usual, legally purchased cannabis, and this was compared to their performance after no cannabis. Participants drove at baseline, at 30 minutes after smoking, and again at 3 hours after smoking. A cognitive battery and subjective tests were given after the drives. Blood was collected at the time of the drives and at baseline for measurement of THC, CBD and metabolites of THC; these values were correlated with psychomotor, subjective and cognitive measures. The results of this study were the first study of the effects of cannabis on driving in older adults. It provided insight into the safety of cannabis in this population and will help to develop public awareness campaigns targeted at this demographic.

Canada was the second country to legalize cannabis at the federal level, putting us in the unique position of being able to study retail cannabis in the lab. In this ecologically valid study, participants smoked their usual preferred cannabis in the lab prior to driving a simulator and undergoing several cognitive and subjective assessments. This study resulted in 1-2 publications as well as a number of conference presentations and was the impetus for a systematic review. In this study we also engaged a panel of people with lived and living experience to advise on the study design and knowledge mobilization. We learned from these panel members that they believed that our study population of adults of 65-79 years of age would likely demonstrate tolerance to the effects of cannabis. This belief was the motivation for a number of further studies.

This study was published in JAMA Open:
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2814053

Read the interviews on:
Yahoo News:
https://www.yahoo.com/lifestyle/is-it-safe-to-drive-after-taking-a-cannabis-edible-heres-what-you-need-to-know-234558197.html

Medical Research.com:
https://medicalresearch.com/author-interviews/even-older-regular-users-of-cannabis-should-refrain-from-driving/

This study was funded by Transport Canada

The Team:
Patricia Di Ciano                 Bruna Brands            Sheng Chen            Wei Wang               
Tarek Rajji                           Jeff Brubacher          Michael McGrath     Omer Hasan
Patrick Byrne                      Christine Wickens    Bernard Le Foll          Pamela Kaduri
Elzohairy Yoassry               Sampson Zhao          Lauren Hong             Stephanie Kwong
Eunice Chen       Amanda De Coninck

This study has now been completed and an educational video can be found here:

An infographic is also provided below