Dose-response of Cannabis and Driving

Dose-dependent Effects of Smoked Cannabis on Simulated Driving Performance

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.

Study Overview

• Status: Completed
• Conditions: Cognitive Impairment; Driving Impaired; Abuse Cannabis
• Intervention / Treatment: Drug: Placebo; Drug: Cannabis

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 36
• Phase: Phase 2

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5S 2S1
      • Center for Addiction and Mental Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 15 years to 41 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Centre for Addiction and Mental Health

Study record dates

Study Major Dates

• Study Start (Actual): June 4, 2021
• Primary Completion (Actual): June 14, 2022
• Study Completion (Actual): June 14, 2022

Study Registration Dates

• First Submitted: August 8, 2018
• First Submitted That Met QC Criteria: August 30, 2018
• First Posted (Actual): September 4, 2018

Study Record Updates

• Last Update Posted (Actual): October 7, 2022
• Last Update Submitted That Met QC Criteria: October 5, 2022
• Last Verified: October 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Chemically-Induced Disorders; Substance-Related Disorders; Marijuana Abuse
• Other Study ID Numbers: 007-2018

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes