Ethanol and Cannabinoid Effects on Simulated Driving and Related Cognition: Sub-Study II (THC-ETOH-II)

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

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

To study the effects of oral ethanol (target BAC of ~0.04g/dl; equivalent to consuming approximately 2 drinks over 1 hour) and vaporized cannabis (~450 mg cannabis plant material at a THC concentration of ~1.7%; roughly equivalent to smoking approximately 1/4 of a marijuana cigarette, or "joint") on driving.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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).
  • Occasional current cannabis users.
  • Experience with drinking 2 or more standard drinks of alcohol at least once in lifetime.
  • Able to provide informed consent.

Exclusion Criteria:

  • Cannabis naïve.
  • Alcohol naïve.
  • 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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Active THC and Placebo Ethanol
Drug: Active inhaled cannabis
~450 mg of active cannabis, which is roughly equivalent to smoking 1/4 of a marijuana cigarette, or "joint". Administered over 20 minutes via a vaporizer.
Drug: Placebo
Approximately 4 drinks of orange juice or ginger ale covered with a trace amount of ethanol on the surface, each administered over approximately 10 minutes.
Drug: Placebo
No active cannabinoids. Administered over 20 minutes via a vaporizer.
Experimental: Active THC and Active Ethanol
Drug: Active inhaled cannabis
~450 mg of active cannabis, which is roughly equivalent to smoking 1/4 of a marijuana cigarette, or "joint". Administered over 20 minutes via a vaporizer.
Drug: Active Oral Ethanol
0.4 g/kg ethanol in orange juice or ginger ale to reach a target BrAC of approximately 0.04%. This dose is equivalent to approximately 2 standard drinks over 1 hour. Approximately 4 drinks, each administered over approximately 10 minutes.
Experimental: Placebo THC and Active Ethanol
Drug: Placebo
Approximately 4 drinks of orange juice or ginger ale covered with a trace amount of ethanol on the surface, each administered over approximately 10 minutes.
Drug: Placebo
No active cannabinoids. Administered over 20 minutes via a vaporizer.
Drug: Active Oral Ethanol
0.4 g/kg ethanol in orange juice or ginger ale to reach a target BrAC of approximately 0.04%. This dose is equivalent to approximately 2 standard drinks over 1 hour. Approximately 4 drinks, each administered over approximately 10 minutes.
Placebo Comparator: Placebo THC and Placebo Ethanol
Drug: Placebo
Approximately 4 drinks of orange juice or ginger ale covered with a trace amount of ethanol on the surface, each administered over approximately 10 minutes.
Drug: Placebo
No active cannabinoids. Administered over 20 minutes via a vaporizer.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Road Tracking Error
Time Frame: baseline, +20, +50, +120, +180 mins after start of alcohol administration
baseline, +20, +50, +120, +180 mins after start of alcohol administration

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Visual Analog Scale (VAS)
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Feeling states associated with alcohol and cannabis intoxication will be measured using this self-report scale of feeling states.
baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Willingness to Drive Scale
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol 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, +20, +50, +120, +180, +240 mins after start of alcohol administration
Cognitive Test Battery
Time Frame: +40 mins after start of alcohol 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.
+40 mins after start of alcohol administration
Number of Joints Scale
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Subjects will be asked to rate the number of standard joints that they believe they have been administered.
baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Number of Drinks Scale
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Subjects will be asked to rate the number of standard drinks that they believe they have been administered.
baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
Biphasic Alcohol Effects Scale (BAES)
Time Frame: baseline, +20, +50, +120, +180, +240 mins after start of alcohol administration
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 administration

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
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

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2016

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 10, 2016

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 10, 2016

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 16, 2016

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 29, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 1501015208.B

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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