NCT05526196

Brief 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.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
60

participants targeted

Target at P25-P50 for not_applicable

Timeline
10mo left

Started Oct 2024

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress66%
Oct 2024Mar 2027

First Submitted

Initial submission to the registry

August 25, 2022

Completed
8 days until next milestone

First Posted

Study publicly available on registry

September 2, 2022

Completed
2.1 years until next milestone

Study Start

First participant enrolled

October 7, 2024

Completed
2.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 1, 2027

Expected
28 days until next milestone

Study Completion

Last participant's last visit for all outcomes

March 1, 2027

Last Updated

March 17, 2026

Status Verified

March 1, 2026

Enrollment Period

2.3 years

First QC Date

August 25, 2022

Last Update Submit

March 16, 2026

Conditions

Driving Under the Influence

Outcome Measures

Primary Outcomes (3)

  • Standard deviation of lateral position

    car 'weaving'

    baseline

  • Standard deviation of lateral position

    car 'weaving'

    15 minutes post smoking

  • Standard deviation of lateral position

    car 'weaving'

    180 minutes post smoking

Secondary Outcomes (39)

  • Speed

    baseline

  • Speed

    15 minutes post smoking

  • Speed

    180 minutes post smoking

  • Reaction time

    baseline

  • Reaction time

    15 minutes post smoking

  • +34 more secondary outcomes

Study Arms (4)

Placebo

OTHER

A cigarette containing placebo cannabis and placebo tobacco

Drug: Placebo

Tobacco

OTHER

A cigarette with placebo cannabis and active tobacco

Drug: Tobacco

Cannabis

OTHER

A cigarette with active cannabis and placebo tobacco

Drug: Cannabis

Tobacco and cannabis

OTHER

A cigarette with active cannabis and active tobacco

Drug: Cannabis tobacco

Interventions

CannabisDRUG

Dried flower cannabis cigarette with 22% THC

Cannabis
TobaccoDRUG

Dried flower cigarette with active nicotine

Tobacco
Cannabis tobaccoDRUG

Dried flower cigarette with active nicotine and cannabis

Tobacco and cannabis
PlaceboDRUG

Dried flower cigarette with both placebo tobacco and cannabis

Placebo

Eligibility Criteria

Age19 Years - 45 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • 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

You may not qualify if:

  • 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)

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Centre for Addiction and Mental Health

Toronto, Ontario, M5T 1R8, Canada

RECRUITING

MeSH Terms

Conditions

Driving Under the Influence

Interventions

nabiximolsTobacco Products

Condition Hierarchy (Ancestors)

Criminal BehaviorBehaviorDangerous Behavior

Intervention Hierarchy (Ancestors)

Smoking DevicesManufactured MaterialsTechnology, Industry, and Agriculture

Central Study Contacts

Patricia Di Ciano

CONTACT

416-535-8501patricia.diciano@camh.ca

Study Design

Study Type
interventional
Phase
not applicable
Allocation
NON RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, INVESTIGATOR
Purpose
BASIC SCIENCE
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 25, 2022

First Posted

September 2, 2022

Study Start

October 7, 2024

Primary Completion (Estimated)

February 1, 2027

Study Completion (Estimated)

March 1, 2027

Last Updated

March 17, 2026

Record last verified: 2026-03

Data Sharing

IPD Sharing
Will not share

Locations

CA(1)