Dose-response of Cannabis and Driving

Study Overview
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Brief Summary
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Epidemiological studies have established a link between collisions while driving and cannabis use. With the changing legal landscape around cannabis, there is much interest in determining per se limits of cannabis while driving. The present study will evaluate driving on a driving simulator after smoking placebo or cannabis with 3 different levels of THC. THC is the active component in cannabis and blood, urine and oral fluid levels of THC will be correlated with driving impairment.

Detailed Description
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Participants will attend the laboratory for 4 separate sessions, separated by about a week. In each session, participants will receive one of 3 doses of smoked cannabis or a placebo. Participants will not know which dose they are receiving. Participants will complete questionnaires, do cognitive tests and drive on a driving simulator before and after smoking the cannabis or placebo cigarette. Blood, urine and oral fluid will be collected throughout the 7-8 hour session to determine levels of THC and its metabolites. These values will be correlated with measures of driving impairment.

Official Title
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Dose-dependent Effects of Smoked Cannabis on Simulated Driving Performance

Conditions
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Driving Impaired, Cognitive Impairment, Abuse Cannabis

Intervention / Treatment
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* Drug: Cannabis
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Near daily use of cannabis (1-5 days/week) confirmed by self-report and urine screening Has held a class G2 or G licence (or equivalent from another jurisdiction) for at least 12 months Willing to abstain from using cannabis for 72 hours prior to each practice or test session Willing to abstain from alcohol for 48 hours prior to each session, and to abstain from all other drugs not medically required for the duration of the study (beginning 48 hours prior to the practice session) Provides written and informed consent Exclusion Criteria: Diagnosis of severe medical or psychiatric condition Meets criteria for current or lifetime alcohol or other substance use disorder, except tobacco use disorder and caffeine use disorder Regular user of medication that may affect cognitive functioning and/or driver performance Family history of schizophrenia or other psychotic disorder Pregnant, looking to become pregnant, or breastfeeding

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This will be a within-subjects, counterbalanced, placebo-controlled study of placebo or 3 doses of cannabis
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Participants will smoke a single smoked placebo (<0.1% THC) cannabis cigarette | Drug: Placebo<br>* Participants will smoke a placebo cigarette<br>|
| Active Comparator: low dose<br>Participants will smoke a single low dose (6.25% THC) of smoked cannabis cigarette | Drug: Cannabis<br>* Participants will smoke as much of the cigarette as they wish<br>|
| Active Comparator: middle dose<br>Participants will smoke a single intermediate dose (12.5% THC) of smoked cannabis cigarette | Drug: Cannabis<br>* Participants will smoke as much of the cigarette as they wish<br>|
| Active Comparator: high dose<br>Participants will smoke a single high dose (22% THC) of smoked cannabis cigarette | Drug: Cannabis<br>* Participants will smoke as much of the cigarette as they wish<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean speed | Speed of driving the simulator | Change in speed of driving between the time before smoking the cigarette and either 30 or 90 minutes after smoking the cigarette | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Standard deviation of lateral position | Driving measures | Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking | 
| reaction time | Driving measures | Change in measure from before smoking the cigarette to either 30 or 90 minutes after smoking | 
| Blood concentrations of THC and metabolites | Blood will be taken to determine how much THC entered the blood | Change from before smoking cigarette to various time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Oral fluid concentrations of THC and metabolites | Participants will provide oral fluid to determine how much THC is in the oral fluid | Change from levels before smoking to 4 time points after smoking: 30 minutes, 90 minutes, 2 hours and 6 hours | 
| Systolic and Diastolic Blood pressure | Vital signs | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Heart rate | Vital signs | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Respirations | Vital signs | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Temperature | Vital signs | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Visual Analog Scales | Tests designed to assess the degree of subjective effects of the drug. The questions will be scored on a scale from 0 to 100 and will consist of: 'I like this drug effect', 'this feels like cannabis', 'I feel this effect', 'I feel this high', 'I feel the good effects', 'I feel the bad effects', 'I feel the rush' | Change from before smoking to a number of time points after smoking: 5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2hours, 3 hours, 4 hours, 5 hours and 6 hours | 
| Verbal free recall test | Test of memory: Participants will be asked to recall words that are read from a list | Change from pre-smoking levels to those observed 60 minutes after smoking | 
| Useful field of view | A computer test for visual processing speed, selective and divided attention | Change from pre-smoking levels to those observed 60 minutes after smoking |