Actively Recruiting
Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes
Led by Centre for Addiction and Mental Health · Updated on 2026-03-17
60
Participants Needed
1
Research Sites
125 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Co-administration of cannabis and tobacco is a common practice, but there is little experimental evidence aimed at understanding the reasons for this prevalence. Some preliminary evidence suggests that tobacco may actually counteract the cognitive-impairing effects of cannabis, and may also increase the subjective ('liking') effects of cannabis, but results are inconclusive. Further, there are no studies into the effects of tobacco on other cannabis-related harms such as driving, or on the ability of tobacco to alter the blood levels of THC, the chemical responsible for the psychoactive properties of cannabis. The purpose of the present study will be to evaluate the effects of tobacco, cannabis or combinations of tobacco and cannabis on driving, cognition, subjective effects and blood THC. Driving will be assessed using a state-of-the-art driving simulator that allows for the safe and objective measurement of the effects of intoxicating substances on driving. Participants will be regular users of cannabis and will be invited to the lab for four counterbalanced test sessions. In these test sessions they will drive the simulator and undergo cognitive tests before and after smoking: 1) cannabis; 2) tobacco; 3) cannabis + tobacco; or 4) placebo. Outcomes will be measured at several time points after smoking the product. Participants will also give blood for determination of levels of THC, and will complete subjective effects questionnaires both before and after smoking the cigarette. This study will be one of the first experimental laboratory studies of the reasons behind co-administration of tobacco and cannabis.
CONDITIONS
Official Title
Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Adults aged 19 years to 45 years
- Smoke or vape cannabis at least once a month but no more than 4 times a week
- Experience with smoked cannabis in the past year
- Report use of at least 100 cigarettes in their lifetime
- Use of any nicotine (smoked, vaped, etc) in the past year
- Hold a G2 or full G driver's license for at least one year
- Willing to abstain from alcohol and other drugs (except medical treatments) for 48 hours before study sessions
- Normal heart rate and blood pressure as determined by the study
- Normal ECG
- Willing to abstain from cannabis for 72 hours and from smoking tobacco for 12 hours before test sessions
- Willing to use an accepted form of contraception during the study
- Past experience co-using cannabis and tobacco
- Provide written and informed consent
You will not qualify if you...
- Use of psychoactive medications or drugs
- Current alcohol or other substance use disorder, including cannabis
- Current or past nicotine dependence
- Withdrawal symptoms as assessed by Marijuana Withdrawal Checklist
- Score less than 10 on Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar)
- Family history of schizophrenia or psychosis
- Respiratory illnesses
- Any serious medical condition preventing participation
- Pregnancy or breastfeeding
- Negative urine screen for cannabis at eligibility assessment
- Neurological disorders affecting cognitive function
- Seeking treatment for tobacco or cannabis use
- Use of more than 5 cigarettes daily
- Use of sedative-hypnotics or other psychoactive drugs contraindicated with cannabis
AI-Screening
AI-Powered Screening
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Trial Site Locations
Total: 1 location
1
Centre for Addiction and Mental Health
Toronto, Ontario, Canada, M5T 1R8
Actively Recruiting
Research Team
P
Patricia Di Ciano
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
DOUBLE
Allocation
NON_RANDOMIZED
Model
CROSSOVER
Primary Purpose
BASIC_SCIENCE
Number of Arms
4
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