Seeing if CBD reduces the effects of THC
Interactions Between Delta-9-THC and CBD: A Controlled Human Drug-administration Study Probing a Harm Reduction Strategy
This trial tests whether different doses of CBD change the effects of THC in adults who regularly use inhaled cannabis.
Quick facts
| Phase | Phase 1 |
|---|---|
| Study type | Interventional |
| Enrollment | 30 (estimated) |
| Ages | 21 Years to 55 Years |
| Sex | All |
| Sponsor | University of California, Los Angeles Academic / other |
| Locations | 1 site (Los Angeles, California) |
| Trial ID | NCT06859710 on ClinicalTrials.gov |
What this trial studies
This phase 1, randomized, placebo-controlled human study at UCLA gives adults who use inhaled cannabis single doses of THC with or without one of several doses of oral CBD or placebo to see how CBD modifies THC's effects. Eligible participants are 21–55 years old, use cannabis 1–7 days per week, and meet medical and psychiatric screening criteria. Researchers will collect subjective effect ratings, pain response measures, cognitive and psychiatric assessments, and safety/laboratory monitoring during and after dosing. The protocol compares placebo, THC alone, and THC combined with 20 mg, 40 mg, or 80 mg CBD to characterize dose-related modulation of both adverse and analgesic effects.
Who should consider this trial
Good fit: Adults 21–55 who inhale cannabis 1–7 days per week, are not seeking treatment for cannabis use, have BMI 18.5–34 kg/m2, are not pregnant or breastfeeding, and agree to use contraception are ideal candidates.
Not a fit: People with severe cannabis or other substance use disorders, significant psychiatric illness, recent use of other illicit drugs, pregnant or breastfeeding individuals, or those who infrequently or never use cannabis are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, the approach could reduce THC-related adverse effects while preserving its pain-relieving benefits.
How similar studies have performed: Prior laboratory studies report mixed results—some show CBD can blunt certain subjective and psychotic-like effects of THC, but the evidence is inconsistent and not definitive.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Male or non-pregnant and non-lactating females aged 21-55 years * Report cannabis use 1-7 days per week over the month prior to screening * Not currently seeking treatment for their cannabis use * History of inhaled cannabis use * Have a Body Mass Index from 18.5 - 34 kg/m2 * Able to perform all study procedures * Must be using a contraceptive (hormonal or barrier methods) Exclusion Criteria: * Meeting DSM-V criteria for severe Cannabis Use disorder (CUD) or any substance use disorder other than nicotine, caffeine, mild or moderate CUD * Evidence of severe psychiatric illness (e.g. mood or anxiety disorder with functional impairment or suicide risk, schizophrenia) judged by the study physician (and PI) to put the participant at greater risk of experiencing adverse events due to completion of study procedures, interfere with their ability to participate in the study, or their capacity to provide informed consent. * Report using other illicit drugs in the prior 4 weeks * Current pain * Pregnancy * Currently enrolled in another research protocol * Not using a contraceptive method (hormonal or barrier methods) * Insensitivity to the cold water stimulus of the Cold Pressor Test * Any disorders that might make cannabis administration hazardous as determined by evaluation physician after review of all medical assessments along with medical history. * Not able to speak and read English
Where this trial is running
Los Angeles, California
- UCLA Center for Cannabis and Cannabinoids — Los Angeles, California, United States (Recruiting)
Study contacts
- Principal investigator: Ziva Cooper, PhD — University of California, Los Angeles
- Study coordinator: Ziva Cooper, PhD
- Email: zcooper@mednet.ucla.edu
- Phone: 310-206-9942
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.