Marijuana's Impact on Alcohol Motivation and Consumption

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02983773

Enrollment

157

Registered

2016-12-06

Start date

2017-01-23

Completion date

2021-07-21

Last updated

2026-04-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Alcohol Drinking, Marijuana

Brief summary

Detailed description

This laboratory study will employ a repeated measures experimental design to examine the effect of high (7.2% THC) and moderate (3.1% THC) dose of marijuana, relative to placebo, on alcohol craving and on behavioral economic measure of alcohol demand after exposure to alcohol cues, and on subsequent drinking in an alcohol choice task in which participants choose either to drink or receive monetary reinforcement for drinks not consumed. Moderators of the marijuana's effects on alcohol-related dependent variables will be tested: DSM5 alcohol use disorder severity, affective vulnerability, trait impulsivity, and working memory functioning. Several empirically-determined mechanisms that may explain why marijuana may increase risk of alcohol relapse and help maintain heavy drinking will be tested as mediators of marijuana's effects on alcohol. The study will recruit 173 non-treatment seeking heavy episodic alcohol drinkers who smoke marijuana at least twice weekly to obtain the final sample of 150 with complete data (15% of attrition). Participants will be tested at a baseline session and during three experimental sessions. Investigators will collect blood samples for analysis of cannabinoid plasma levels and to examine marijuana-induced changes in hormones and other biomarkers potentially related to appetite, inflammation and stress. Collection of these biomarkers would allow for a greater understanding about the mechanisms whereby marijuana may acutely increase alcohol motivation and use. The findings will inform researchers and clinicians about how marijuana acutely increases alcohol craving and consumption. The strategy of this proposal is to use the most comprehensive controlled test characterizing marijuana's putative effects on alcohol.

Interventions

DRUGTHC 7.2%

1 smoked marijuana cigarette with 7.2% THC

DRUGTHC 3.1%

1 smoked marijuana cigarette with 3.0% THC

DRUGPlacebo

1 smoked placebo marijuana cigarette

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

BASIC_SCIENCE

Masking

DOUBLE (Subject, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

21 Years to 44 Years

Healthy volunteers

Yes

Inclusion criteria

* Age 21 to 44 * English-speaking * marijuana smoking in past month * report of current heavy episodic (binge) drinking * in good physical health and weighing \< 250 lbs * zero breath alcohol at each visit

Exclusion criteria

* history of seizures * smoking \>20 tobacco cigarettes per day * positive pregnancy test * nursing * positive urine toxicology screen for drugs other than cannabis * interest to quit or receive treatment for marijuana or alcohol use * meeting criteria for a current affective disorder (depression, or mania, panic disorder, and having psychotic symptoms as assessed by the SCID)

Design outcomes

Primary

Measure	Time frame	Description
Alcohol Craving	T0: pre-smoking (-45 minutes) and post smoking at 12 mins (T1), 47 mins (T2), and 58 mins (T3), 116 mins (T4), 178 mins (T5) during the experimental session	Alcohol Craving Questionnaire-Short Form-Revised (ACQ-SF-R) is a 12-item state measure of alcohol craving in the current moment (i.e., right now), scored on a 7-point Likert scale, from (1) strongly disagree to (7) strongly agree, with higher scores indicating greater craving. Scores on this measure are averaged to yield a total craving score.

Secondary

Measure	Time frame	Description
Percent of Total Available Alcohol Consumed	post-smoking during two-hour alcohol choice task during the experimental session	Participants completed two 60-minute blocks in the bar lab, during which they could drink up to eight mini-drinks of their personal choice with total amount of alcohol available designed to raise blood levels up to 0.10 g/dl or receive monetary reinforcement (in each block $12 tab in which each drink is worth $3) for drinks not consumed. The primary dependent variable for this task is percent of total available alcohol consumed.

Countries

United States

Contacts

PRINCIPAL_INVESTIGATORJane Metrik, PhD

Brown University

Participant flow

Recruitment details

157 participants were randomized to the experimental session order at the first experimental session and all completed the first experimental session. 131 participants completed all three experimental sessions.

Baseline characteristics

Characteristic	—
Age, Continuous	25.66 years STANDARD_DEVIATION 5.13
Ethnicity (NIH/OMB) Hispanic or Latino	34 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	121 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	2 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants
Race (NIH/OMB) Asian	4 Participants
Race (NIH/OMB) Black or African American	23 Participants
Race (NIH/OMB) More than one race	12 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants
Race (NIH/OMB) Unknown or Not Reported	16 Participants
Race (NIH/OMB) White	101 Participants
Sex: Female, Male Female	53 Participants
Sex: Female, Male Male	104 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk
deaths Total, all-cause mortality	0 / 157	0 / 157	0 / 157
other Total, other adverse events	0 / 157	1 / 157	0 / 157
serious Total, serious adverse events	0 / 157	0 / 157	0 / 157

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 22, 2026