Cannabis brownies and booze: study reveals how they mess with your driving
NCT ID NCT04931095
First seen Jun 24, 2026 · Last updated Aug 04, 2026 · Updated 3 times
Summary
This study looked at how eating cannabis (in a brownie) and drinking alcohol, alone or together, affects people's ability to think clearly, stay coordinated, and drive safely. Sixty healthy adults aged 21 to 55 took part in a controlled lab setting. Researchers measured impairment using driving simulators, sobriety tests, and thinking tasks to understand the combined effects.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Cannabis (in a brownie) and alcohol (in a flavored drink)
- What this could lead to
- If successful, this could help set clearer guidelines for how long people should wait after using cannabis or drinking before driving.
- What could go wrong
- This was a small, early-phase lab study with 60 healthy adults, so results may not apply to everyone or to real-world cannabis use (e.g., smoking).
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 1
The first testing in people. Mainly checks safety and dose, usually in a small group.
- Participants
-
70 people
The number who actually took part.
- Started
-
Feb 2022
- Finished
-
Aug 2025
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
21 to 55 years
- Sex
-
Anyone
- Healthy volunteers
-
Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Have provided written informed consent 2. Be between the ages of 21 and 55 3. Be in good general health based on a physical examination, medical history, vital signs, and screening urine and blood tests 4. Not be pregnant or nursing (if female). All females must have a negative serum pregnancy test at the screening visit and a negative urine pregnancy test at each study visit. 5. Have a body mass index (BMI) in the range of 19 to 36 kg/m2 6. Blood pressure at Screening Visit does not exceed a systolic blood pressure (SBP) of 150 mmHg or a diastolic blood pressure (DBP) of 90 mmHg 7. Have not donated blood in the prior 30 days. 8. Report at least 2 days of binge drinking in the past 90 days (greater than 4 or 5 drinks on a single occasion for women and men, respectively) 9. Report ≥ 1 use of cannabis in the past year 10. Provide negative urine test for illicit drug use (excluding THC) and negative breath alcohol test (0% BAC) at screening and before study sessions 11. Report at least 1 instance of simultaneous alcohol and use in the past year. Exclusion Criteria: 1. Psychoactive drug use (aside from cannabis, nicotine, alcohol, or caffeine) in past month 2. Current use of over-the-counter (OTC) drugs, supplements/vitamins, or prescription medications that, in the opinion of the investigator or medical staff, will impact the participant's safety 3. History of or current evidence of significant medical condition 4. Evidence of current psychiatric condition \[(MINI for Diagnostic and Statistical Manual (DSM)-V)\] 5. Meet criteria for severe alcohol use disorder (MINI for DSM-V) 6. Clinical Institute Withdrawal Assessment for Alcohol scale (CIWA-Ar) score \> 9 7. Been in treatment previously for alcohol or cannabis use disorder 8. Use of cannabis, on average, more than 2 times/week over past 3 months 9. Liver function tests more than 2x normal range 10. Enrollment in another clinical trial or receiving of any drug as part of research within past 30 days 11. Shipley vocabulary score \<18 (corresponds to 5th grade reading level).
Get updates
Get notified about this study
Sign up to get updates when this study changes or when new studies for Alcohol intoxication are added.
Genom att skicka in godkänner du våra Användarvillkor
Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
Johns Hopkins Behavioral Pharmacology Research Unit
Baltimore, Maryland, 21224, United States
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Does alcohol blunt the instinct to step in? study tests bystander behavior
- Band-Aid like patch could track alcohol levels without a blood test
- Keto diet may alter Alcohol's effects on the brain
- Virtual programs tested to save alaska native youth from suicide
- Scientists scan brains of drinking pairs to uncover social secrets
- Uber and lyft: do they reduce drunk driving crashes?