NCT06259916

Brief Summary

This is a randomized, parallel-group study designed to explore the differences between cannabis intoxication, alcohol intoxication and co-intoxication involving both alcohol and cannabis, utilizing electroencephalography (EEG) as well as more traditional intoxication measures such as breath alcohol concentration and balance metrics. If eligible for the study, participants will be randomized to complete one study session in our mobile laboratory, during which they will use either alcohol, cannabis (which will be self-administered, ad libitum) or both alcohol and cannabis.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
99

participants targeted

Target at P50-P75 for not_applicable

Timeline
1mo left

Started Jan 2024

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress97%
Jan 2024May 2026

Study Start

First participant enrolled

January 5, 2024

Completed
4 days until next milestone

First Submitted

Initial submission to the registry

January 9, 2024

Completed
1 month until next milestone

First Posted

Study publicly available on registry

February 14, 2024

Completed
2.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 30, 2026

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

May 30, 2026

Last Updated

November 13, 2025

Status Verified

November 1, 2025

Enrollment Period

2.4 years

First QC Date

January 9, 2024

Last Update Submit

November 12, 2025

Conditions

Outcome Measures

Primary Outcomes (3)

  • Electroencephalography (EEG) Objective Cognitive Function Measures--Amplitude (microvolts)

    The EEG amplitude (measured in microvolts) will be obtained while participants perform the speeded visual flanker task

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

  • Electroencephalography (EEG) Objective Cognitive Function Measures--Latency (milliseconds)

    The EEG latency (measured in milliseconds) will be obtained while participants perform the speeded visual flanker task

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

  • Standing postural stability

    An iPod Touch will be attached to each participant's hip with a simple elastic/Velcro strap. An app on the device will record fine grained movements while they try to stand as still as possible for 30-60 seconds under four conditions that vary in terms of demand on the proprioceptive system (eyes open, eyes closed), and on a stable vs. soft (foam) surface.

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

Other Outcomes (5)

  • Breath Alcohol Concentration

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

  • Blood Delta-9-tetrahydrocannabinol (THC) Levels

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

  • Blood Cannabidiol (CBD) Levels

    Immediately pre-substance use, 1-hour post-use, 2-hours post-use, 4-hours post-use

  • +2 more other outcomes

Study Arms (3)

Cannabis Group

EXPERIMENTAL

Participants in this group will self-administer their own flower cannabis product (that they purchased for use in the study from a legal-market dispensary) ad libitum inside their homes. Researchers will not handle the product or instruct participants on how much to use during the session.

Other: Cannabis

Alcohol Group

EXPERIMENTAL

Participants in this group will be administered a dose of alcohol by researchers in our mobile lab. The dose is designed (based on participant sex and body weight) to bring blood alcohol concentration to .06 g/dL.

Other: Alcohol

Alcohol + Cannabis Group

EXPERIMENTAL

Participants in this group will first self-administer their own flower cannabis product (that they purchased for use in the study from a legal-market dispensary) ad libitum inside their homes. Researchers will not handle the product or instruct participants on how much to use during the session. They will then return to the mobile lab which will be parked outside their residence and will be administered a dose of alcohol by researchers. The dose is designed (based on participant sex and body weight) to bring blood alcohol concentration to .06 g/dL.

Other: AlcoholOther: Cannabis

Interventions

AlcoholOTHER

Participants in this condition will receive the standard alcohol dose

Alcohol + Cannabis GroupAlcohol Group

Participants in this group will self-administer legal-market flower cannabis

Alcohol + Cannabis GroupCannabis Group

Eligibility Criteria

Age21 Years - 50 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • years old
  • Heavy drinkers (consuming more than 4 drinks/day or more than 14 drinks/week for men, or more than 3 drinks/day or more than 7 drinks/week for women)
  • Regular users of legal-market flower cannabis (at least 2x/week in past 3 months)
  • report simultaneously using alcohol and legal-market flower cannabis at least once per month in the past 3 months
  • English speakers.

You may not qualify if:

  • Daily tobacco users
  • Diagnosed with or seeking treatment for alcohol use disorder (AUD) or other substance use disorder (SUD)
  • Females cannot be pregnant, breastfeeding or trying to become pregnant
  • Meet criteria for psychotic, bipolar or major depressive disorder with suicidal ideation, or history of these disorders, 5) Current use of psychotropic (except anti-depressants)
  • Report illicit drug use in past 60-days or fail drug screen on the day of the study appointment
  • Major medical condition contraindicating alcohol and/or cannabis consumption.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Colorado State University

Fort Collins, Colorado, 80523, United States

RECRUITING

MeSH Terms

Conditions

Alcohol Drinking

Interventions

Ethanolnabiximols

Condition Hierarchy (Ancestors)

Drinking BehaviorBehavior

Intervention Hierarchy (Ancestors)

AlcoholsOrganic Chemicals

Study Officials

  • Hollis Karoly, PhD

    Colorado State University

    PRINCIPAL INVESTIGATOR
  • Patricia Davies, PhD

    Colorado State University

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
OTHER
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

January 9, 2024

First Posted

February 14, 2024

Study Start

January 5, 2024

Primary Completion (Estimated)

May 30, 2026

Study Completion (Estimated)

May 30, 2026

Last Updated

November 13, 2025

Record last verified: 2025-11

Locations