Ethanol + Cannabis Effects on DUI

(THC-ETOH-II Trial)

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: Yale University

Disqualifiers: Cannabis naïve, Alcohol naïve, Pregnancy, Hearing deficits

Compensation: Varies

Number of Visits: 2

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how alcohol and cannabis affect driving and thinking skills. Participants will join different groups to try either both substances, just one, or neither, and then engage in driving simulations. The study aims to understand how these substances might impact road safety. Individuals who have occasionally used cannabis (also known as marijuana) and have consumed at least two alcoholic drinks in their lifetime might be suitable candidates.

As a Phase 1 trial, the research focuses on understanding how the treatment works in people, offering participants the opportunity to contribute to groundbreaking insights.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that both cannabis and alcohol affect driving safety. Studies have found that cannabis slows reaction time, affects coordination, and alters perception, increasing the risk of accidents. Similarly, alcohol greatly increases crash risk, especially as blood levels rise.

Despite their impairing effects, these substances are commonly used and have been extensively studied. This research enhances understanding of their negative effects. The current trial, in its early stages, focuses on assessing the safety and tolerability of these substances in a controlled setting.

While cannabis and alcohol are legal in many areas and have been widely researched, this trial aims to further explore their impact on driving and cognitive skills. This controlled study will expand existing knowledge, providing more insights into their effects. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about this trial because it explores how the combination of cannabis and ethanol affects driving under the influence (DUI). Unlike standard DUI studies that often look at alcohol or cannabis individually, this trial examines their combined impact, which is more reflective of real-world scenarios where people might use both substances. This approach could provide new insights into how these substances interact and affect cognitive and motor functions, potentially leading to updated DUI regulations and public safety guidelines. By understanding these interactions better, the trial aims to improve road safety and inform policies that could reduce DUI incidents.

What evidence suggests that this trial's treatments could be effective for DUI?

This trial will compare the effects of different combinations of cannabis and ethanol on driving. Research has shown that both cannabis and alcohol impair driving safety. When combined, their negative effects worsen. A review of studies found that using these substances together harms driving skills more than using either one alone. Cannabis may cause some impairments, and studies suggest potential risks. Alcohol is well-known to impair driving, with research confirming reduced performance even at low levels. These findings indicate that both substances, especially when combined, can significantly affect safe driving. ^{1 2 3 6 7}

Are You a Good Fit for This Trial?

This trial is for men and women aged 21-55 who occasionally use cannabis and have had at least two alcoholic drinks at some point. They must be able to consent to the study. People can't join if they've never used cannabis or alcohol, are pregnant, or have hearing problems.

Inclusion Criteria

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

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants receive oral ethanol and vaporized cannabis to study their effects on simulated driving and cognition

1 day

1 visit (in-person)

Cognitive Testing

Participants undergo cognitive tests to assess the effects of alcohol and THC on driving-related cognition

Approximately 4 hours

1 visit (in-person)

Follow-up

Participants are monitored for any delayed effects of the substances administered

1 week

What Are the Treatments Tested in This Trial?

Interventions

• Cannabis
• Ethanol

Trial Overview The study aims to understand how drinking alcohol (ethanol) and inhaling cannabis affect simulated driving and thinking skills. Participants will receive either a placebo, actual ethanol, or active inhaled cannabis to compare their effects.

How Is the Trial Designed?

Group I: Placebo THC and Active Ethanol Experimental Treatment 2 Interventions

Group II: Active THC and Placebo Ethanol Experimental Treatment 2 Interventions

Group III: Active THC and Active Ethanol Experimental Treatment 2 Interventions

Group IV: Placebo THC and Placebo Ethanol Placebo Group 1 Intervention

Cannabis is already approved in Canada, United States, European Union for the following indications:

Approved in Canada as Cannabis for:

• Chronic pain
• Nausea and vomiting associated with chemotherapy
• Spasticity associated with multiple sclerosis

Approved in United States as Cannabis for:

• Seizures associated with Lennox-Gastaut syndrome and Dravet syndrome
• Nausea and vomiting associated with chemotherapy

Approved in European Union as Cannabis for:

• Spasticity associated with multiple sclerosis
• Chronic pain

Who Is Running the Clinical Trial?

Yale University

Lead Sponsor

Trials

1,963

Recruited

3,046,000+

Published Research Related to This Trial

In a study involving 11 healthy volunteers, very low doses of ethanol and THC were tested in combination, but the results showed no evidence of synergistic effects on cognitive performance or subjective responses.

The combined effects of these substances were not stronger than their individual effects, and in some cases, they were even less effective when taken together.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Combined effects of acute, very-low-dose ethanol and delta(9)-tetrahydrocannabinol in healthy human volunteers. Ballard, ME., de Wit, H.[2021]

In a study of 120 adults, those using cannabis with predominantly CBD consumed significantly fewer alcoholic drinks and had fewer drinking days compared to those using cannabis with predominantly THC or a combination of CBD and THC.

These results suggest that CBD may help reduce alcohol consumption, supporting previous preclinical findings and highlighting the importance of cannabinoid content in understanding alcohol and cannabis co-use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

THC and CBD effects on alcohol use among alcohol and cannabis co-users. Karoly, HC., Mueller, RL., Andrade, CC., et al.[2021]

In a survey of 533 cannabis users who drink alcohol, those using cannabis to treat a medical condition reported drinking less frequently than those who do not use cannabis for treatment.

The type of cannabis used affects alcohol consumption; individuals using high-THC/CBD cannabis tended to drink more on days they used cannabis compared to those using medium or low-THC/CBD cannabis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Investigating Relationships Between Alcohol and Cannabis Use in an Online Survey of Cannabis Users: A Focus on Cannabinoid Content and Cannabis for Medical Purposes. Karoly, HC., Mueller, RL., Andrade, CC., et al.[2021]

Preliminary studies suggest that cannabidiol (CBD) may reduce alcohol consumption and protect against some harmful effects of alcohol, such as liver and brain damage, based on both preclinical and limited human research.

However, there is a lack of comprehensive studies on the interactions between CBD and alcohol in humans, making it difficult to draw definitive conclusions about their combined effects and potential therapeutic implications for alcohol use disorder.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of cannabidiol on alcohol-related outcomes: A review of preclinical and human research. Nona, CN., Hendershot, CS., Le Foll, B.[2019]

A significant portion of cannabis products (58.5%) lacked information on CBD content, and most products (72-100%) with CBD fell into the highly intoxicating THC:CBD ratio category (≥1:1), suggesting that patients may experience enhanced acute effects and intoxication.

Medical and recreational cannabis products are largely similar, posing a risk for patients seeking therapeutic benefits, as they may inadvertently consume high-potency products that lead to unwanted side effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Potency and Therapeutic THC and CBD Ratios: U.S. Cannabis Markets Overshoot. Pennypacker, SD., Cunnane, K., Cash, MC., et al.[2022]

In a study with alcohol-preferring rats, combining ethanol and THC significantly impaired memory in an object recognition task, highlighting the risks of co-abusing these substances.

The memory impairment was linked to the activation of CB1 receptors, as a specific antagonist reversed the effects of THC, indicating a potential mechanism for the observed synergistic action between ethanol and THC.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Memory impairment following combined exposure to delta(9)-tetrahydrocannabinol and ethanol in rats. Ciccocioppo, R., Antonelli, L., Biondini, M., et al.[2019]

Alcohol use significantly increases the risk of injury, with a relative risk of 3.00 for those who consumed alcohol within six hours prior to injury, indicating a strong dose-response relationship.

Interestingly, cannabis use was associated with a lower risk of injury (relative risk of 0.33), suggesting a potential protective effect, although this finding should be interpreted cautiously due to the small number of cannabis users in the study.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Alcohol and cannabis use as risk factors for injury--a case-crossover analysis in a Swiss hospital emergency department. Gmel, G., Kuendig, H., Rehm, J., et al.[2022]

In a study of injured drivers presenting to emergency departments in cannabis-legal states, 8% reported cannabis use within 8 hours before a motor vehicle collision (MVC), but biosample testing revealed a higher prevalence of 18%.

High-risk crash features were prevalent among drivers using cannabis, whether alone or with alcohol; however, seriously injured patients were less likely to report cannabis use compared to alcohol use, indicating potential differences in the impact of these substances on crash severity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cannabis presentations to the emergency department after MVC in the era of legalization for recreational use. Choo, EK., Nishijima, D., Trent, S., et al.[2022]

In a study involving 10 healthy volunteers, CBD alone did not impair motor or psychomotor performance, while alcohol significantly did, indicating that CBD may not negatively affect cognitive functions on its own.

When combined with alcohol, CBD resulted in lower blood alcohol levels compared to alcohol alone, suggesting that CBD may mitigate some effects of alcohol, although the overall impairments in performance remained similar.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Interaction of cannabidiol and alcohol in humans. Consroe, P., Carlini, EA., Zwicker, AP., et al.[2019]

Cannabis and alcohol both impair driving skills, but cannabis effects vary more between individuals due to factors like tolerance and smoking technique, while alcohol consistently increases crash risk.

Combining cannabis with alcohol significantly worsens driving impairment compared to using either substance alone, highlighting the need for caution and advising cannabis users to wait several hours before driving.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of cannabis compared with alcohol on driving. Sewell, RA., Poling, J., Sofuoglu, M.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC2722956/

THE EFFECT OF CANNABIS COMPARED WITH ... Surprisingly, given the alarming results of cognitive studies, most marijuana-intoxicated drivers show only modest impairments on actual road tests.

2. cdc.gov cdc.gov/cannabis/health-effects/driving.html

Cannabis and Driving If you intend to drive, the safest option is not to use any alcohol or drugs, including cannabis. Here are steps you can take to help prevent ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S0379073823003043

Driving under the influence of cannabis: A 5-year ... The aim of this study was to examine the concentration of cannabinoids in blood samples of driving-under-the-influence (DUI) offenders.

4. aaafoundation.org aaafoundation.org/evaluation-data-drivers-arrested-driving-influence-relation-per-se-limits-cannabis/

An Evaluation of Data from Drivers Arrested for Driving ... This study examines the relationship between toxicological test results and performance on a battery of physiological and psychomotor measures used by law ...

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9940647/

Cannabis Effects on Driving Performance At 40–100 min post-dose, SDLP was significantly increased after THC-dominant (2.33 cm, 95% CI, 0.08–3.86; p < 0.001) and THC/CBD-equivalent ...

6. codot.gov codot.gov/safety/impaired-driving/druggeddriving

Drugged Driving | Meet the Effects When someone is high behind the wheel, the chances of a crash are doubled, and the chances of a DUI are even higher. The average cost of a DUI is $13,500 for ...

7. sciencedirect.com sciencedirect.com/science/article/pii/S0001457525001927

Evaluation of the causal impact of recreational marijuana ... Findings show a lagged rise in traffic fatalities particularly after retail sales. •. Results challenge previous claims dismissing a marijuana–crash link. •.