THC and CBD: A Controlled Human Study Probing a Harm Reduction Strategy (THC-REDUX)

Interactions Between Delta-9-THC and CBD: A Controlled Human Drug-administration Study Probing a Harm Reduction Strategy

The purpose of this research is to assess the impact of CBD on the effects of THC.

Study Overview

• Status: Recruiting
• Conditions: Pain; Abuse, Drug
• Intervention / Treatment: Drug: Placebo; Drug: THC; Drug: CBD 20 mg; Drug: CBD 40 mg; Drug: CBD 80 mg

Detailed Description

Some evidence indicates that cannabidiol (CBD), a non-intoxicating cannabis component, might mitigate certain effects of THC. This study will examine possible roles for CBD in modulating THC's adverse and analgesic effects.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Vincent Acebo; Phone Number: 310-983-3417; Email: vacebo@mednet.ucla.edu
• Study Contact Backup: Name: Ziva Cooper, Phd; Phone Number: 310-206-9942; Email: zcooper@mednet.ucla.edu

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • Recruiting
      • UCLA Center for Cannabis and Cannabinoids
      • Contact: Ziva D Cooper, PhD; Phone Number: (310) 794 -1497; Email: cannabislab@mednet.ucla.edu
      • Contact: Vince Acebo; Email: vacebo@mednet.ucla.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; 0 mg THC, 0 mg CBD	Drug: Placebo; Vaporized Placebo; Other Names: Cannabis
Active Comparator: THC; 20 mg THC, 0 mg CBD	Drug: THC; Vaporized THC (20 mg); Other Names: Cannabis
Active Comparator: CBD 20; 0 mg THC, 20 mg CBD	Drug: CBD 20 mg; Vaporized CBD (20 mg); Other Names: Cannabis
Active Comparator: CBD 40; 0 mg THC, 40 mg CBD	Drug: CBD 40 mg; Vaporized CBD (40 mg); Other Names: Cannabis
Active Comparator: CBD 80; 0 mg THC, 80 mg CBD	Drug: CBD 80 mg; Vaporized CBD (80 mg); Other Names: Cannabis
Active Comparator: THC with CBD 20; 20 mg THC, 20 mg CBD	Drug: THC; Vaporized THC (20 mg); Other Names: Cannabis; Drug: CBD 20 mg; Vaporized CBD (20 mg); Other Names: Cannabis
Active Comparator: THC with CBD 40; 20 mg THC, 40 mg CBD	Drug: THC; Vaporized THC (20 mg); Other Names: Cannabis; Drug: CBD 40 mg; Vaporized CBD (40 mg); Other Names: Cannabis
Active Comparator: THC with CBD 80; 20 mg THC, 80 mg CBD	Drug: THC; Vaporized THC (20 mg); Other Names: Cannabis; Drug: CBD 80 mg; Vaporized CBD (80 mg); Other Names: Cannabis

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Subject-rated drug effects of abuse liability	Subject ratings of "Good Drug Effect" as measured using a visual analog scale (1-100 mm)	3 hours
Analgesia as measured using the Cold Pressor Test	Pain threshold assessed using the Cold Pressor Test (percent baseline)	3 hours
Behavioral task performance as assessed by the DRUID App Score	Trough composite scores on the DRUID App	3 hours
Pharmacokinetics of THC	Peak plasma levels of THC (ng/ml)	3 hours

Collaborators and Investigators

• Sponsor: University of California, Los Angeles
• Investigators: Principal Investigator: Ziva Cooper, PhD, University of California, Los Angeles

Study record dates

Study Major Dates

• Study Start (Actual): November 5, 2025
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: February 25, 2025
• First Submitted That Met QC Criteria: March 3, 2025
• First Posted (Actual): March 5, 2025

Study Record Updates

• Last Update Posted (Actual): December 17, 2025
• Last Update Submitted That Met QC Criteria: December 15, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: CBD; Cannabis; THC
• Additional Relevant MeSH Terms: Neurologic Manifestations; Mental Disorders; Chemically-Induced Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Substance-Related Disorders; Marijuana Abuse; Organic Chemicals; Hydrocarbons; Terpenes; Cannabinoids; Dronabinol; nabiximols
• Other Study ID Numbers: 24-5306; 93306 (Other Grant/Funding Number: CA Department of Cannabis Control)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No