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

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% and THC (1.05 mg in a 70 kg individual) 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 naive.
  • Alcohol naive.
  • Positive pregnancy screen
  • Hearing deficits.

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 delta-9-THC
Low dose (0.015 mg/kg = 1.05 mg in a 70 kg individual) THC, dissolved in alcohol. This dose is roughly equivalent to smoking approximately 1/4 of a marijuana cigarette, or "joint". Administered over 20 minutes.
Drug: Placebo
Control: small amount of alcohol (quarter teaspoon), with no THC. Administered over 20 minutes.
Drug: Placebo
Control: no alcohol, administered for a total of 80 minutes.
Experimental: Active THC and Active Ethanol
Drug: Active delta-9-THC
Low dose (0.015 mg/kg = 1.05 mg in a 70 kg individual) THC, dissolved in alcohol. This dose is roughly equivalent to smoking approximately 1/4 of a marijuana cigarette, or "joint". Administered over 20 minutes.
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.
Experimental: Placebo THC and Active Ethanol
Drug: Placebo
Control: small amount of alcohol (quarter teaspoon), with no THC. Administered over 20 minutes.
Drug: Placebo
Control: no alcohol, administered for a total of 80 minutes.
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.
Placebo Comparator: Placebo THC and Placebo Ethanol
Drug: Placebo
Control: small amount of alcohol (quarter teaspoon), with no THC. Administered over 20 minutes.
Drug: Placebo
Control: no alcohol, administered for a total of 80 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Road Tracking Error
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
changes in road tracking errors between timepoints to assess the effects of alcohol and THC on road tracking errors.
baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Biphasic Alcohol Effects Scale (BAES)
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol and THC infusion
A scale designed to assess the stimulant and sedative effects associated with alcohol intoxication.
baseline, +20, +50, +120, +180, +240 mins after start of alcohol and THC infusion
Visual Analog Scale (VAS)
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Feeling states associated with alcohol and cannabis intoxication will be measured using this self-report scale of feeling states.
baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Cognitive Test Battery
Time Frame: +40 mins after start of alcohol and THC infusion
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.
+40 mins after start of alcohol and THC infusion
Willingness to Drive Scale
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
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, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Number of Joints Scale
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Subjects will be asked to rate the number of standard joints that they believe they have been administered.
baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Number of Drinks Scale
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion
Subjects will be asked to rate the number of standard drinks that they believe they have been administered.
baseline, +20, +50, +120, +180 mins after start of alcohol and THC infusion

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

December 1, 2015

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

March 26, 2015

First Submitted That Met QC Criteria

March 30, 2015

First Posted (Estimated)

March 31, 2015

Study Record Updates

Last Update Posted (Actual)

April 29, 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

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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