New study to test if age changes how cannabis affects driving
NCT ID NCT04325958
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study looks at how age and how often someone uses cannabis affect driving skills. Researchers will compare young (19-25) and middle-aged (35-45) drivers who use cannabis occasionally or frequently. Participants will smoke a cannabis cigarette or a placebo and then drive in a simulator to measure weaving, speed, and following distance.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Cannabis (marijuana)
- What this could lead to
- If successful, this study could help understand how age and cannabis use frequency impact driving ability, potentially informing safer driving guidelines.
- What could go wrong
- This is an early-phase observational study with a small sample (128 participants) using a driving simulator, not real roads. Results may not reflect real-world driving or apply to all users.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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About 128 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Mar 2024
- Expected to finish
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Mar 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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19 to 45 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
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.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Centre for Addiction and Mental Health
RECRUITINGToronto, Ontario, M5S 2S1, Canada
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