NCT05526196

Combined and Separate Effects of Cannabis and Tobacco: Psychomotor, Subjective and Physiological Outcomes

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: Centre for Addiction and Mental Health · Academic / Other
• Sex: All
• Age: 19 Years – 45 Years
• Healthy volunteers: Accepted

Summary

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

• Driving Under the Influence

Interventions

Type	Name	Description
DRUG	Cannabis	Dried flower cannabis cigarette with 22% THC
DRUG	Tobacco	Dried flower cigarette with active nicotine
DRUG	Cannabis tobacco	Dried flower cigarette with active nicotine and cannabis
DRUG	Placebo	Dried flower cigarette with both placebo tobacco and cannabis

Timeline

• Start date: 2024-10-07
• Primary completion: 2027-02-01
• Completion: 2027-03-01
• First posted: 2022-09-02
• Last updated: 2026-03-17

Locations

1 site across 1 country: Canada