THC Testing for Cannabis Impairment

(NHTSA-II Trial)

Overseen By Diana King, B.A

Age: 18 - 65

Sex: Any

Trial Phase: Phase 1

Sponsor: Yale University

Disqualifiers: Pregnancy, Cancer, Epilepsy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to understand how smoking cannabis affects thinking and driving skills. Researchers are testing medium THC marijuana (a form of cannabis with moderate levels of the psychoactive compound THC) and a placebo to compare their effects. They seek individuals who have recently and frequently used cannabis, have experienced its psychoactive effects, and possess at least two years of highway driving experience. Participants will be evaluated on how cannabis use influences their cognitive abilities and simulated driving performance.

As a Phase 1 trial, this research focuses on understanding cannabis's impact on cognitive and driving skills, offering participants a chance 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. However, you cannot participate if you have a serious medical condition or if you test positive for drugs or alcohol (except THC) on the test day.

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

Research shows that medium THC marijuana can alter mood and perception, potentially affecting thinking and reactions. Studies indicate that THC can slow reaction time and impair coordination. However, not all effects are negative. Some studies found no impact on specific driving skills, such as braking or steering speed. Despite this, the risk of car accidents increases after using THC. Awareness of these possible effects is important when considering joining a trial. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about this trial because it aims to better understand how medium THC levels in marijuana affect impairment, a topic with limited clarity despite the increasing legalization of cannabis. Unlike current roadside tests that measure THC presence without assessing impairment, this study could lead to more accurate impairment tests, potentially revolutionizing safety measures. The trial's findings might pave the way for a new standard in cannabis impairment assessment, which could have significant implications for law enforcement and public safety.

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

This trial will compare the effects of Medium THC Marijuana and Placebo Marijuana. Research has shown that marijuana with medium THC levels can impact brain function, particularly in tasks requiring memory and focus. This may alter how well individuals remember or concentrate. Some studies suggest that regular THC users might develop tolerance, reducing the effects over time. However, immediately after cannabis use, individuals may experience altered perception and time sense, potentially affecting activities like driving. One study found that after a few days without cannabis, frequent users showed no driving issues, suggesting the effects may diminish over time. ^{6 7 8 9 10}

Who Is on the Research Team?

Godfrey Pearlson, M.D

Principal Investigator

Yale University

Are You a Good Fit for This Trial?

This trial is for people aged 18-55 with a driver's license and at least 2 years of driving experience. Participants should be English speakers who have used cannabis recently and felt its effects. Excluded are those with adverse reactions to cannabis, low IQ, new users, drug or alcohol use on test day (except THC), pregnant or breastfeeding women, individuals unable to understand study instructions, former users abstaining from cannabis, anyone with significant head trauma or medical conditions affecting cognition.

Inclusion Criteria

Able and willing to provide written informed consent, and willing to commit to the study protocol

Able to read, speak, and understand English

I have a driver's license and over 2 years of driving experience.

Exclusion Criteria

My high blood pressure is not under control.

I have had a head injury that made me unconscious for more than 30 minutes or caused a concussion for 30 days.

Positive screen for drug and alcohol (except THC) on test day will result in rescheduling the appointment

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 day

1 visit (in-person)

Dose Visit

Participants receive placebo and high THC marijuana doses, followed by cognitive and driving tests

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after dosing

1 day

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Medium THC
• Placebo THC

Trial Overview The study tests the effects of smoked marijuana on tasks related to driving skills and cognitive functions over time after use. It compares medium THC levels against a placebo in participants with prior marijuana experience. The goal is to better understand how recent use impairs behavior relevant to driving.

How Is the Trial Designed?

Group I: Placebo Marijuana Experimental Treatment 1 Intervention

Placebo Marijuana will be administered.

Group II: Medium THC Marijuana Experimental Treatment 1 Intervention

Medium THC marijuana will be administered.

Who Is Running the Clinical Trial?

Yale University

Lead Sponsor

Trials

1,963

Recruited

3,046,000+

National Highway Traffic Safety Administration (NHTSA)

Collaborator

Trials

8

Recruited

940+

Hartford Hospital

Collaborator

Trials

140

Recruited

19,700+

National Institute on Drug Abuse (NIDA)

Collaborator

Trials

2,658

Recruited

3,409,000+

Published Research Related to This Trial

A meta-analysis of 10 randomized controlled trials involving 2,027 participants found that behavioral therapies (BTs) significantly improve outcomes for cannabis use disorders compared to control conditions, with an effect size of 0.44, indicating that patients receiving BTs fared better than 66% of those in control groups.

Behavioral therapies were effective in reducing both the frequency and severity of cannabis use, as well as improving psychosocial functioning, with larger effect sizes observed in studies using waitlist controls compared to those with active control comparisons.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Behavioral therapies for treatment-seeking cannabis users: a meta-analysis of randomized controlled trials. Davis, ML., Powers, MB., Handelsman, P., et al.[2022]

A standardized dose of CannEpil, a medicinal cannabis oil, did not significantly impair overall driving performance but did lead to increased variability in speed and weaving during a simulated drive, particularly noticeable between 20 and 30 minutes after administration.

Changes in eye behavior, such as increased fixation duration and altered blink patterns, suggest that eye tracking could be a useful tool for assessing cannabis-related driver impairment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of CannEpil® on simulated driving performance and co-monitoring of ocular activity: A randomised controlled trial. Manning, B., Hayley, AC., Catchlove, S., et al.[2023]

This paper introduces a framework for assessing the safety of additives in cannabis concentrates, aimed at helping regulators and manufacturers without extensive toxicological expertise.

Based on data from over 54,000 users of smart vaporization devices, the study suggests a standard consumption assumption of 100 mg per day for cannabis concentrates to facilitate risk assessments of these additives.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A First-Tier Framework for Assessing Toxicological Risk from Vaporized Cannabis Concentrates. Vreeke, S., Faulkner, DM., Strongin, RM., et al.[2022]

The safety of cannabis and cannabinoid medications is a significant concern, and while some safety information can be drawn from recreational use studies, medical and recreational users may experience different effects.

There is a pressing need for long-term safety monitoring of cannabinoid use in patients, as clinical experience is still developing, which will help inform both therapeutic decisions and public policy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety issues concerning the medical use of cannabis and cannabinoids. Ware, MA., Tawfik, VL.[2019]

Clinical studies on cannabis administration are essential for understanding its effects and developing treatments for cannabis dependence, with different methods of administration (smoking, oral, intravenous) each having unique safety and efficacy profiles.

Acute adverse effects from cannabis can include tachycardia, cognitive impairment, and anxiety, necessitating careful screening and monitoring of participants to ensure safety during research studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Methods for clinical research involving cannabis administration. Gorelick, DA., Heishman, SJ.[2019]

A daily dose of 40 mg of rimonabant for 15 days effectively reduced the physiological effects of smoked cannabis, such as tachycardia, similar to a single higher dose of 90 mg on the first day of treatment.

While the 40 mg dose significantly decreased subjective effects of cannabis on day 8, it did not maintain this effect by day 15, indicating that repeated dosing may not consistently reduce the subjective experience of cannabis effects over time.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Single and multiple doses of rimonabant antagonize acute effects of smoked cannabis in male cannabis users. Huestis, MA., Boyd, SJ., Heishman, SJ., et al.[2019]

Citations

1. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2829657

Brain Function Outcomes of Recent and Lifetime Cannabis ... These findings suggest that cannabis use is associated with short- and long-term brain function outcomes, especially during working memory tasks.

2. ccsa.ca ccsa.ca/sites/default/files/2019-04/CCSA-Cannabis-Use-Cognitive-Effects-Report-2019-en.pdf

Regular Use and Cognitive Functioning The acute effects of cannabis include euphoria and relaxation, changes in perception, time distortion, deficits in attention span and memory, body tremors, ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8006301/

Duration of Neurocognitive Impairment With Medical ... There is evidence that medical cannabis patients who use THC regularly develop tolerance to many of the impairing effects of THC (25).

4. today.ucsd.edu today.ucsd.edu/story/frequent-cannabis-users-show-no-driving-impairment-after-two-day-break

Frequent Cannabis Users Show No Driving Impairment After ... After at least 48 hours of abstinence, frequent cannabis users showed no impartments in driving performance in a driving simulator study ...

5. link.springer.com link.springer.com/article/10.1007/s00406-024-01880-2

Cannabis, cannabinoids and health: a review of evidence ... Orally administered cannabis produces a protracted increase in blood THC concentration and prolongs impaired driving performance compared to ...

6. nida.nih.gov nida.nih.gov/research-topics/cannabis-marijuana

Cannabis (Marijuana) | National Institute on Drug Abuse Cannabis products with THC can cause changes in mood, thoughts, and perceptions of reality. These products can also cause harmful health effects ...

7. samhsa.gov samhsa.gov/substance-use/learn/marijuana/risks

Know the Effects, Risks and Side Effects of Marijuana Research shows that people who use marijuana are more likely to have relationship problems, worse educational outcomes, lower career achievement, and reduced ...

8. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8416748/

Cannabis, Impaired Driving, and Road Safety - PubMed Central No effects were seen on braking reaction times, steering reaction time, lane-keeping speed control, intersection crossing, vigilance, obstacle ...

9. aaafoundation.org aaafoundation.org/wp-content/uploads/2024/12/202412-AAAFTS-Cannabis-Fact-Sheet-Traffic-Safety.pdf

202412_Cannabis Fact Sheet_Traffic Safety THC impairs driving, with 6% of drivers reporting driving within an hour of using marijuana in 2021. Studies show increased crash risk, but some reviews ...

10. cdc.gov cdc.gov/cannabis/health-effects/index.html

Cannabis Health Effects It can slow reaction time and ability to make decisions. · Cannabis can impair coordination and distort perception. · The use of multiple ...