NCT07176208

Clinical Study to Evaluate the Effects of Oral Delta-9-tetrahydrocannabinol (Δ9-THC) With and Without Alcohol on Perception and Driving Performance in Healthy Adults

Dose Ranging Clinical Study to Evaluate the Effects of Oral Delta-9-tetrahydrocannabinol (Δ9-THC) With and Without Alcohol on Perception and Driving Performance in Healthy Adults

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 48 (estimated)
• Sponsor: Food and Drug Administration (FDA) · Federal
• Sex: All
• Age: 21 Years – 55 Years
• Healthy volunteers: Accepted

Summary

With the increasing prevalence and use of cannabis products by the public, there exists a need to better understand the safety impact of cannabis use, particularly when it comes to subjective perceptions of drug effect and driving impairment. This study aims to evaluate the dose-dependent effects of oral Δ9-THC alone and in combination with alcohol (0.08% BAC \[Blood Alcohol Concentration\]) on driving performance and subjective feeling in healthy adults. The results of this study will address current knowledge gaps on the effects of oral Δ9-THC on driving impairment across a clinically relevant dose range.

Detailed description

The cannabis plant contains bioactive compounds known as cannabinoids, with delta-9 tetrahydrocannabidiol (Δ9-THC) and cannabidiol (CBD) being the most well-known cannabinoids in varieties of cannabis. With the increasing prevalence and use of cannabis products by the public, there exists a need to better understand the safety impact of cannabis use, particularly when it comes to subjective perceptions of drug effect and driving impairment. Studies have evaluated the effects of Δ9-THC on perception and driving capacity, however they have largely focused on inhaled routes of administration in experienced users and at relatively high doses. Research on the impact of oral Δ9-THC use in occasional users at lower doses (10 mg and below) on driving capacity is limited. Furthermore, despite the increasing prevalence of concurrent cannabis and alcohol use, there also remains a significant gap in research examining the combined effects of oral THC and alcohol on driving performance. This study aims to evaluate the dose-dependent effects of oral Δ9-THC alone and in combination with alcohol (0.08% BAC \[Blood Alcohol Concentration\]) on driving performance and subjective feeling in healthy adults. These effects will also be compared to the established alcohol-related impairment benchmark of blood alcohol content (0.08% BAC). The inclusion of an alcohol-only arm targeting 0.08% BAC will serve as a relevant positive control, representing the legal intoxication threshold in most states in the USA and providing a well-characterized impairment baseline against which THC and THC/alcohol combination effects can be measured. The results of this study will address current knowledge gaps on the effects of oral Δ9-THC on driving impairment across a clinically relevant dose range. In this randomized, double-blind, 6-period crossover study, 48 healthy adult volunteers with driving experience and previous cannabis exposure will receive single oral doses across six treatment conditions: 5 mg THC, 10 mg THC, 5 mg THC combined with alcohol (target BAC of 0.08%), 10 mg THC combined with alcohol (target BAC of 0.08%), alcohol alone (target BAC of 0.08%), and matched placebo, with washout periods between treatments. The study will evaluate the dose-dependent effects of Δ9-THC (with and without alcohol) on both objective driving performance and subjective participant experience. Objectives primarily include standardized driving simulator assessments measuring standard deviation of lateral position (SDLP) and standard deviation of speed (SDSP), as well as subjective effects measured through use of Visual Analogue Scales (VAS). Assessments will be conducted at baseline and predetermined intervals post-dose over 24 hours.

Conditions

• Cannabis, Drug Effects
• Driving Performance

Interventions

Type	Name	Description
DRUG	5 mg Dronabinol (Marinol®) + Placebo Beverage	Subjects in this arm will receive one dose of 5 mg THC (Dronabinol) with a placebo beverage in one of the assigned treatment days.
DRUG	10 mg Dronabinol (Marinol®) + Placebo Beverage	Subjects in this arm will receive one dose of 10 mg THC (Dronabinol) with a placebo beverage in one of the assigned treatment days.
DRUG	5 mg Dronabinol (Marinol®) + Alcohol Beverage	Subjects in this arm will receive one dose of 5 mg THC (Dronabinol) with an alcoholic beverage (to achieve a target BAC of 0.08%) in one of the assigned treatment days.
DRUG	10 mg Dronabinol (Marinol®) + Alcohol Beverage	Subjects in this arm will receive one dose of 10 mg THC (Dronabinol) with an alcoholic beverage (to achieve a target BAC of 0.08%) in one of the assigned treatment days.
DRUG	Placebo Capsule + Alcohol Beverage	Subjects in this arm will receive placebo capsule with an alcoholic beverage (to achieve a target BAC of 0.08%) in one of the assigned treatment days.
DRUG	Placebo Capsule + Placebo Beverage	Subjects in this arm will receive a placebo capsule with a placebo beverage in one of the assigned treatment days.

Timeline

• Start date: 2025-12-29
• Primary completion: 2026-04-14
• Completion: 2026-04-14
• First posted: 2025-09-16
• Last updated: 2026-01-16

Locations

2 sites across 1 country: United States

Regulatory

• FDA-regulated drug study