Exploring how CBD affects THC's psychoactive effects

Modulation of ∆9-tetrahydrocannabinol Acute Psychoactive Effects by Ranging Doses of Cannabidiol in Healthy, Occasional Cannabis Users: a Controlled, Triple Blind, Randomized, Cross-over Study

PHASE1; PHASE2 · Centre hospitalier de l'Université de Montréal (CHUM) · NCT06099379

This study is testing how different amounts of CBD can change the effects of THC when people inhale them together.

Quick facts

PhasePHASE1; PHASE2
Study typeInterventional
Enrollment100 (estimated)
Ages21 Years to 49 Years
SexAll
SponsorCentre hospitalier de l'Université de Montréal (CHUM) (other)
Locations1 site (Montreal, Quebec)
Trial IDNCT06099379 on ClinicalTrials.gov

What this trial studies

This study aims to investigate the modulation of THC's psychoactive effects by CBD at various ratios and doses. Participants will inhale different combinations of CBD and THC to assess their behavioral and pharmacological responses. The research seeks to fill gaps in understanding how CBD influences THC effects, which is crucial for public safety and informed cannabis use. By evaluating these interactions, the study hopes to provide insights that can guide regulatory bodies and improve cannabis consumption guidelines.

Who should consider this trial

Good fit: Ideal candidates are adults aged 21 to 49 who have used cannabis at least once and have limited recent use.

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

Why it matters

Potential benefit: If successful, this study could help patients and consumers make more informed choices about cannabis products, potentially enhancing safety and efficacy.

How similar studies have performed: While there is ongoing research into cannabinoid interactions, this specific approach to studying CBD's modulation of THC effects is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Between 21 and 49 years of age, inclusively;
2. Have used cannabis at least once in their lifetime and have used cannabis three days or less in the 30 days prior to enrollment;
3. Be able to provide a signed informed consent;
4. Willing to comply with study procedures and requirements as per protocol;
5. Have a forced expiratory volume in first second (FEV) less than or equal to 90 %;
6. Able to communicate and understand English or French language;
7. For female participants:

   a. No childbearing potential, defined as: i. postmenopausal (12 months of spontaneous amenorrhea and ≥ 45 years of age); or ii. Documented surgically sterilized (i.e., tubal ligation, hysterectomy, or bilateral oophorectomy); or b. For female of childbearing potential: i. Must have negative pregnancy test result at screening and at subsequent visits.

ii. AND have no pregnancy plan while on the study iii. AND must agree to use a medically accepted method of birth control throughout the study.

Exclusion criteria

Participants will be excluded if any of the following criteria are met:

1. Any disabling medical condition, as assessed by medical history, physical exam, vital signs and/or laboratory assessments that, in the opinion of the study physician, precludes safe participation in the study or the ability to provide fully informed consent;
2. Severe psychiatric condition (history of schizophrenia, schizoaffective disorder or bipolar disorder; current acute psychosis, mania or current suicidality based on the Mini International Neuropsychiatric Interview);
3. Any other disabling, unstable or acute mental condition that, in the opinion of the study physician, precludes safe participation in the study or ability to provide fully informed consent;
4. Known chronic liver disease or aspartate transaminase/alanine transaminase (AST/ALT) two times higher than upper limit of normal values at screening visit;
5. Blood pressure higher than 130/80 mmHg;
6. Kidney disorders;
7. Bleeding disorders;
8. Current moderate or severe DSM-5 substance use disorder (except nicotine) according to SCID-V;
9. Currently pregnant, breastfeeding or planning to become pregnant either at screening or while enrolled in the study;
10. Pending legal action or other reason that, in the opinion of the study physician, might prevent study completion;
11. Use of medication within 7 days of experimental sessions; which, in the opinion of the Investigator, may interact with cannabis.
12. Participation in clinical studies or undergoing other investigational procedure involving cannabis or cannabinoids administration within 30 days prior to randomization.
13. Resting heart rate over 100 beats per minute.
14. Current body mass index (BMI) over 29.9 kg/m2.
15. Any clinically significant electrocardiogram abnormalities at screening visit.

Where this trial is running

Montreal, Quebec

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.

View on ClinicalTrials.gov →

Conditions: Cannabis, THC

Last reviewed 2026-05-15 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.