Effects of cannabis on driving in young versus middle-aged users

The Influence of Age on Driving-related Cannabis Effects: Exploring Cannabis Use Frequency and Related Factors

Not applicable Interventional Centre for Addiction and Mental Health · NCT04325958

This study tests how smoking cannabis affects the driving skills of young and middle-aged people by comparing their performance in a driving simulator.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment128 (estimated)
Ages19 Years to 45 Years
SexAll
SponsorCentre for Addiction and Mental Health Academic / other
Locations1 site (Toronto, Ontario)
Trial IDNCT04325958 on ClinicalTrials.gov

What this trial studies

This study investigates how cannabis affects simulated driving performance in young and middle-aged drivers. Participants will be divided into two age groups and further categorized as occasional or frequent cannabis users. Each participant will attend two test sessions, where they will smoke either a cannabis cigarette or a placebo before driving in a simulator. Blood samples will be collected to measure THC levels, and cognitive tasks will be performed to assess the impact of cannabis on driving abilities.

Who should consider this trial

Good fit: Ideal candidates are individuals aged 19-25 or 35-45 who use cannabis recreationally and hold a valid driver's license.

Not a fit: Patients who do not use cannabis or are outside the specified age ranges may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide valuable insights into the effects of cannabis on driving, potentially influencing public policy and safety regulations.

How similar studies have performed: While there have been studies on cannabis and driving, this specific investigation focusing on age differences and user frequency is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria

* 19-25 or 35-45 years of age;
* Use of smoked cannabis at least once in the past 6 months.
* Use of smoked or vaped cannabis primarily for recreational purposes on up to 1 day per week or on at least 6 days per week in the past 3 months;
* Holds a class G or G2 Ontario driver's licence (or equivalent from another jurisdiction) for at least 12 months;
* Willing to abstain from using alcohol for 24 hours and cannabis for 72 hours prior to Practice and Test Sessions;
* Willing to abstain from all other drugs not prescribed for medical purposes for 48 hours prior to Practice and Test Sessions;
* Resides within Toronto (study site) or can reside with friends/family in Toronto after a Test Session; this area may be extended to the Greater Toronto area if recruitment challenges arise;
* Participant willing to use appropriate contraception until their participation in the study is completed;
* Provides written and informed consent.

Exclusion Criteria

* Use of cannabis primarily for therapeutic purposes, or equally for therapeutic and recreational purposes;
* Diagnosis of medical condition that contraindicates use of cannabis determined by self-report as judged by the Principal Investigator and a study physician; this includes a history of hypersensitivity to cannabinoids smoke, respiratory disease and/or severe cardiovascular, cerebrovascular, renal or liver disease, and bleeding disorders. Smoking cannabis is not recommended for individuals with respiratory diseases, and they will be excluded;
* Diagnosis of psychiatric condition that contraindicates use of cannabis determined by self-report or SCID-5;
* Participants of childbearing potential: Pregnancy (point-of-care test) or breastfeeding;
* Meets criteria for current or lifetime alcohol or other substance use disorder (DSM-5), except tobacco use disorder and caffeine use disorder;
* Is a regular user of medications that affect brain function (based on self-report); this includes concomitant therapy with sedative-hypnotics or other psychoactive drugs
* Use of anti-hypertensives;
* First-degree relative diagnosed with schizophrenia or another psychotic disorder.
* Participation in a past driving study at CAMH (to limit practice effects).
* Participation in a clinical study concurrent with their participation in this study.

Where this trial is running

Toronto, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Cannabis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.