Alcohol and Cannabis Concentrates Co-Administration

Exploring Intoxication During Acute Alcohol and Cannabis Concentrate Co-Administration: A Focus on Cannabinoid Content and Order Effects

The goal of this study is to learn about the effects of combining alcohol with cannabis concentrate products which contain high levels of THC. The main question[s] it aims to answer are, 1) How does the order in which someone consumes THC and alcohol in a given co-use session impact outcomes such as blood alcohol level, heart rate or subjective drug effects, and 2) how does THC percentage in cannabis influence outcomes following alcohol and cannabis co-administration. Participants will be scheduled for our mobile lab to come to their residence. During the session, they will:

• consume a standardized dose of alcohol as well as use their own preferred cannabis concentrate product.
• they will then remain in our mobile lab for about 4 hours and complete some surveys as well as do some cognitive tasks on an iPad every 30 minutes.
• They will also have their blood drawn three times throughout the session, and will periodically be asked to blood into a breathalyzer to measure blood alcohol level.

Researchers will compare people who use alcohol prior to cannabis to those who use cannabis prior to alcohol to determine whether order of use impacts outcomes.

Study Overview

• Status: Completed
• Conditions: Alcohol Use Disorder; Cannabis Use
• Intervention / Treatment: Other: commercially available alcohol administered prior to commercially available cannabis; Other: commercially available cannabis administered prior to commercially available alcohol

Detailed Description

Individuals who drink alcohol commonly report co-using cannabis, and the increasing availability of new formulations of highly potent cannabis products on the legal market means that alcohol is likely being combined with cannabis products that contain high levels of delta-9-tetrahydrocannabinol (THC). There is limited existing research on the acute effects of cannabis products containing high amounts of THC, such as cannabis concentrates, which often contain up to 90% THC. Existing laboratory data suggests that consuming alcohol and cannabis together (compared to alcohol alone) is associated with reduced BAC, delayed time to peak blood alcohol concentration (BAC), longer duration of intoxication, and increased subjective intoxication, but it is unknown how cannabis concentrates may interact with alcohol to influence these outcomes. There is also a lack of research regarding whether timing or order of use matters, though recent survey data from our group and others suggests that using alcohol before cannabis may confer additional risk compared to using cannabis prior to alcohol. The present study leverages a federally-compliant mobile laboratory design to explore the acute effects of self-administered cannabis concentrates alongside a standardized dose of alcohol. The investigators will recruit a community sample of individuals who regularly use alcohol and cannabis to participate study sessions in our mobile laboratory. The sessions will involve individuals consuming cannabis concentrates of their choice (that they acquire themselves) along with a standardized dose of alcohol. Half of the participants will use the alcohol before cannabis, and the other half will use the cannabis before alcohol. The investigators will measure intoxication and biological outcomes every 30 minutes for 4 hours. The investigators will also measure differences between those who used alcohol before cannabis and those who used cannabis before alcohol.

• Study Type: Interventional
• Enrollment (Actual): 146
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Fort Collins, Colorado, United States, 80523
      • Colorado State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. 21-65 years old,
2. Heavy drinkers (for men, >4 drinks in one occasion, or >14 drinks per week; for women, >3 drinks in one occasion, or >7 drinks per week)
3. Regular users of legal-market cannabis (at least 3x/week in past 3 months)
4. Have experience using cannabis concentrates within the last year
5. Willing to obtain a concentrate product of their choice for use in the study.

Exclusion Criteria:

1. Diagnosed with or seeking treatment for alcohol use disorder (AUD) or other substance use disorder (SUD)
2. Pregnant, breastfeeding or trying to become pregnant
3. Meet criteria for psychotic, bipolar or major depressive disorder with suicidal ideation, or history of these disorders
4. Current use of psychotropic (except anti-depressants) or steroid medications
5. Report illicit drug use in past 60-days or fail drug screen (drug screen tests for the presence of amphetamines, benzodiazepines, cocaine, THC, methamphetamine and opioids; only THC is allowed to be present in urine in order to be eligible to participate in the study
6. Major medical condition contraindicating alcohol and/or cannabis consumption (e.g., liver disease, heart disease, or being told by a doctor that it is unsafe to consume alcohol or cannabis due to a medical condition)
7. Have participated in another research study in the past 8 weeks.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Alcohol before Cannabis; Participants are randomly assigned to receive the standardized alcohol dose during the experimental session prior to going inside their residence to self-administer their preferred cannabis concentrate product.	Other: commercially available alcohol administered prior to commercially available cannabis; Researcher administered alcohol prior to self-administration of cannabis
Experimental: Cannabis before alcohol; Participants are randomly assigned to go inside their residence to self-administer their preferred cannabis concentrate product and then receive the standardized alcohol dose.	Other: commercially available cannabis administered prior to commercially available alcohol; Self administration of cannabis prior to researcher administered alcohol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Breath Alcohol Level (BrAC)	Breath alcohol level will be measured using a breathalyzer repeatedly during the experimental session	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)
Alcohol Urge Questionnaire (AUQ)	The AUQ is a self-report measure of urge for alcohol and has been validated for real-time assessment of alcohol craving in the laboratory. The total score on the measure ranges from 0-48 where higher is worse	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)
Heart Rate (HR)	Heart rate (beats per minute) is measured using a finger pulse oximeter	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)
ARCI Marijuana Scale	The ARCI scale measures subjective responses to cannabis. total score ranges from 0-12 where higher is worse	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)
DRUID Psychomotor Battery	The DRUID is a mobile app that tests for cognitive and motor impairment, and has been shown to detect impairment related to alcohol and cannabis use. total score ranges from 0-100 where higher is worse.	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood-THC	We will quantify levels of THC in the blood before and after the participant uses their cannabis product	Blood is drawn immediately prior to alcohol and cannabis consumption, again 60 minutes post alcohol administration start time, and again 240 minutes post alcohol start time
Biphasic Effects of Alcohol Scale (BAES)	The BAES measures the stimulating and sedating effects of alcohol and is validated for use in laboratory settings. This scale produces a stimulation subscale (total score ranges from 0-70 where higher is more stimulated) and a sedation subscale (total score ranging from 0-70 where higher is more sedated)	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)
Profile of Mood States (POMS)	The POMS is a self-report rating scale that assesses state-level, distinct mood states. The POMS produces multiple subscales (Tension, depression, anger, fatigue, confusion, vigour, as well as a total mood disturbance scale)	Baseline (pre ingestion) and every 30 minutes (post ingestion) for a total of 270 minutes (9 measures)

Collaborators and Investigators

• Sponsor: University of Colorado, Denver
• Collaborators: Colorado State University; Institute of Cannabis Research, Colorado State University Pueblo
• Investigators: Principal Investigator: Hollis C Karoly, PhD, University of Colorado, Denver

Study record dates

Study Major Dates

• Study Start (Actual): December 16, 2021
• Primary Completion (Actual): August 1, 2024
• Study Completion (Actual): August 1, 2024

Study Registration Dates

• First Submitted: August 11, 2023
• First Submitted That Met QC Criteria: August 11, 2023
• First Posted (Actual): August 21, 2023

Study Record Updates

• Last Update Posted (Actual): November 18, 2025
• Last Update Submitted That Met QC Criteria: November 14, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: alcohol; cannabis; polysubstance use; psychomotor impairment; cannabis concentrates
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Neurobehavioral Manifestations; Substance-Related Disorders; Chemically-Induced Disorders; Alcohol-Related Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Alcoholism; Marijuana Abuse; Psychomotor Disorders; Organic Chemicals; Alcohols; Ethanol
• Other Study ID Numbers: 2161

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No