Ethanol and Cannabinoid Effects on Simulated Driving and Related Cognition: Substudy III (THC-ETOH-III)

April 23, 2026 updated by: Deepak C. D'Souza, Yale University
The overarching goal of this study is to characterize the effects of ethanol and cannabinoids on simulated driving and related cognition.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

To study the effects of ethanol clamped at BAC 0.04% (equivalent to consuming approximately 2 drinks over 1 hour) and oral Dronabinol (10 mg capsule) on driving.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Connecticut
      • West Haven, Connecticut, United States, 06516
        • Biological Studies Unit, VA Connecticut Healthcare System

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 55 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Males or females 21 to 55 years of age (extremes included).
  • Exposed to cannabis at least once.
  • Exposed to alcohol at least once.
  • Able to provide informed consent.

Exclusion Criteria:

  • Cannabis naïve
  • Alcohol naïve
  • Positive pregnancy screen
  • Hearing deficits
  • Sesame oil allergy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active THC and Placebo Ethanol
Drug: Active Dronabinol
10 mg capsule of Dronabinol will be administered orally.
Drug: Placebo
Control: no alcohol, administered for ~80 minutes.
Drug: Placebo
Control: Placebo pill (no active cannabinoids) administered orally.
Experimental: Active THC and Active Ethanol
Drug: Active Ethanol
Target BrAC of 0.04% reached over 20 minutes and then clamped to maintain this dose for an additional 60 minutes. This dose is equivalent to consuming approximately 2 drinks over 1 hour. Administered over a total of 80 minutes.
Drug: Active Dronabinol
10 mg capsule of Dronabinol will be administered orally.
Experimental: Placebo THC and Active Ethanol
Drug: Active Ethanol
Target BrAC of 0.04% reached over 20 minutes and then clamped to maintain this dose for an additional 60 minutes. This dose is equivalent to consuming approximately 2 drinks over 1 hour. Administered over a total of 80 minutes.
Drug: Placebo
Control: no alcohol, administered for ~80 minutes.
Drug: Placebo
Control: Placebo pill (no active cannabinoids) administered orally.
Placebo Comparator: Placebo THC and Placebo Ethanol
Drug: Placebo
Control: no alcohol, administered for ~80 minutes.
Drug: Placebo
Control: Placebo pill (no active cannabinoids) administered orally.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline: Road Tracking Error
Time Frame: baseline, +100, +210 mins after start of dronabinol administration
baseline, +100, +210 mins after start of dronabinol administration

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change from Baseline: Biphasic Alcohol Effects Scale (BAES)
Time Frame: baseline, +60, +90, +210, +360 mins after start of dronabinol administration
A scale designed to assess the stimulant and sedative effects associated with alcohol intoxication.
baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Change from Baseline: Visual Analog Scale (VAS)
Time Frame: baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Feeling states associated with alcohol and cannabis intoxication will be measured using this self-report scale of feeling states.
baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Change from Baseline: Cognitive Test Battery
Time Frame: baseline, +120 mins after start of dronabinol administration

Several computer tasks will be administered to assess alcohol and THC effects on driving related cognition, including:

visual vigilance, visual motor function, attention and working memory, and processing speed.
baseline, +120 mins after start of dronabinol administration
Change from Baseline: Willingness to Drive Scale
Time Frame: baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Subjects will be asked to rate their willingness to drive at their current state in the context of various scenarios including willingness to drive from testing facility to a number of destinations that are different driving distances.
baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Change from Baseline: Number of Joints Scale
Time Frame: baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Subjects will be asked to rate the number of standard joints that they believe they have been administered.
baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Change from Baseline: Number of Drinks Scale
Time Frame: baseline, +60, +90, +210, +360 mins after start of dronabinol administration
Subjects will be asked to rate the number of standard drinks that they believe they have been administered.
baseline, +60, +90, +210, +360 mins after start of dronabinol administration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Yale University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2016

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

March 10, 2016

First Submitted That Met QC Criteria

March 10, 2016

First Posted (Estimated)

March 16, 2016

Study Record Updates

Last Update Posted (Actual)

April 27, 2026

Last Update Submitted That Met QC Criteria

April 23, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1501015208.C

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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