Effects of cannabis and tobacco on driving and cognition
Official title: Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes
Run by Centre for Addiction and Mental Health · NCT05526196 · Data updated 2026-11-12
This study tests how smoking or vaping cannabis and tobacco affects driving skills and thinking abilities in adults who use both substances.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 19 Years to 45 Years |
| Sex | All |
| Enrollment | 60 (estimated) |
| Sponsor | Centre for Addiction and Mental Health Academic / other |
| Locations | 1 site (Toronto, Ontario) |
| Status | Recruiting |
| Started | October 7, 2024 |
| Main results expected | February 1, 2027 |
| Study ends | March 1, 2027 |
| Registry record updated | March 17, 2026 |
| Trial ID | NCT05526196 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are adults aged 19 to 45 who use cannabis and tobacco regularly but do not have a cannabis use disorder.
✕Probably not a fit
Patients who do not use cannabis or tobacco, or those with a history of cannabis use disorder, may not benefit from this study.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This study investigates how cannabis and tobacco, both separately and in combination, affect driving performance, cognitive function, and subjective experiences. Using a state-of-the-art driving simulator, the research aims to objectively measure the impact of these substances on driving abilities and blood THC levels. Participants will be adults who smoke or vape cannabis and have experience with tobacco, allowing for a focused examination of these common co-uses. The study seeks to clarify the potential counteractive effects of tobacco on cannabis-induced impairment.
Why it matters
Potential benefit: If successful, this study could provide valuable insights into the safety of cannabis and tobacco use, particularly in relation to driving.
How similar studies have gone: While there is preliminary evidence regarding the interaction of cannabis and tobacco, this study represents a novel approach to understanding their combined effects on driving and cognition.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * • Adults aged 19 years to 45 years (to control for the effects of age on cognition) * Smoke or vape cannabis at least once a month but no more than 4 times a week (to avoid enrolling people with cannabis use disorder who may experience withdrawal when asked to abstain from cannabis) * Experience with smoked cannabis in the past year * Report use of at least 100 cigarettes in their lifetime to ensure familiarity with the tobacco used in the present study * Use of any nicotine (smoked, vaped, etc) in the past year * G2 or full G driver's licence for at least a year * Willing to abstain from alcohol and other drugs (other than drugs required for treatment of a medical condition) for 48 hours prior to study session * Normal heart rate and blood pressure as determined by the QI (because cannabis and tobacco increase heart rate) * Normal ECG (because cannabis and tobacco increase heart rate) * Willing to abstain from cannabis for 72 hours prior to the test session and from smoking tobacco for 12 hours * Willing to use an accepted form of contraception during the study (both males and females) * Past lifetime experience with co-use of cannabis or tobacco (either simultaneous or concurrent) * Provides written and informed consent Exclusion Criteria: * • Use of psychoactive medications or drugs * Current alcohol or other substance use disorder, including cannabis (as assessed with the SCID) * Current or past nicotine dependence (to avoid precipitating a relapse) * Withdrawal symptoms as assessed with the Marijuana Withdrawal Checklist \[57, 58\] * A score of less than 10 on the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) \[59\] * Family history of schizophrenia or psychosis (to avoid giving cannabis to anyone with a predisposition to psychosis) * Respiratory illnesses (due to the smoked route of administration in this study) * Any serious medical condition precluding participation as judged by the responsible study physician * Pregnancy or breastfeeding * Negative urine screen for cannabis at eligibility assessment (to ensure experience with cannabis) * Neurological disorders that may affect cognitive function * Treatment-seeking for tobacco or cannabis use * Use of more than 5 cigarettes a day (to avoid confound of the effects of chronic smoking on measures) * Concomitant therapy with sedative-hypnotics or other psychoactive drugs (counter-indicated with cannabis)
Where it's running
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Centre for Addiction and Mental Health
Toronto, Ontario, Canada Recruiting
Study contacts
- Study coordinator: Patricia Di Ciano
- Email: patricia.diciano@camh.ca
- Phone: 416-535-8501
Similar studies
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.