THC for Driving Performance

Overseen By Heather Barkholtz, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Phase < 1

Sponsor: University of Wisconsin, Madison

Must not be taking: Mood stabilizers, sedatives

Disqualifiers: Substance use disorder, pregnancy, others

Compensation: Varies

Number of Visits: Unknown

Duration: 9 months

5 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial requires that you do not use medications that may impact driving ability, such as mood stabilizers or sedatives.

What data supports the effectiveness of the drug for driving performance?

Research shows that THC, including its form as dronabinol, can impair driving performance, especially in occasional users, due to its effects on neurobehavioral skills. However, heavy users may show less impairment due to tolerance, and the effects can last beyond the period of elevated THC levels. ^{1 2 3 4 5}

Is THC safe for human use?

THC, including its variants like Delta-8-THC and Delta-9-THC, has been shown to have both therapeutic benefits and potential adverse effects. While it can help with conditions like nausea, pain, and appetite stimulation, it may also impair cognitive functions such as memory and perception, and cause unpleasant psychological reactions. Delta-8-THC is similar to Delta-9-THC but may have fewer undesirable effects, though high doses can lead to medical emergencies. Overall, more research is needed to fully understand its safety profile. ^{1 6 7 8 9}

How does the drug THC differ from other treatments for driving performance?

THC, specifically Delta-8-THC and Delta-9-THC, is unique in its ability to impair driving performance by affecting cognitive and psychomotor skills, which are crucial for safe driving. Unlike other treatments, THC's psychoactive effects can lead to significant impairment, making it important to understand its impact on driving abilities. ^{1 8 10 11 12}

What is the purpose of this trial?

This study is being done to assess the feasibility of administrating Δ9-THC and Δ8-THC isolates and simultaneously adopting several data harmonization measures to generate uniquely translatable data. This project aims to (1) evaluate the feasibility and acceptability of administering ∆9-THC and Δ8-THC isolates using standardized cannabis dosing units to quantify ∆9-THC and Δ8-THC pharmacokinetics; and (2) evaluate the feasibility and acceptability of adopting standardized impairment detection methods and driving performance definitions and measures on quantifying ∆9-THC and Δ8-THC driving impairment compared to a placebo.

Research Team

Heather Barkholtz, PhD

Principal Investigator

University of Wisconsin, Madison

Eligibility Criteria

This trial is for people aged 18-49 who have used cannabis in the last two years, are in good mental health, don't have major medical issues, speak English, and can drive (with a valid license and at least two years of experience).

Inclusion Criteria

Recent cannabis use (within past two years)

Good mental health as determined by self-reported responses to the Psychopathology Screener

Absence of any major medical, cardiovascular, endocrine, and neurological condition as determined by self-reported responses to the Medical History Screener

Exclusion Criteria

Any serious prior adverse response to cannabis

History of or current substance use disorder as determined by self-reported responses to the Internalizing, Externalizing, and Substance Use Disorder Screener

Pregnancy or lactation (pregnancy test, if needed)

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive Δ9-THC and Δ8-THC isolates or placebo to evaluate pharmacokinetics and driving impairment

9 months

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Delta-8-THC
• Delta-9-THC

Trial Overview The study tests how Δ9-THC and Δ8-THC affect driving. Participants will receive either one of these cannabis compounds or a placebo to see how it impacts their driving skills using standardized dosing and impairment detection methods.

Participant Groups

Group I: delta-9-THC Experimental Treatment 1 Intervention

Group II: delta-8-THC Experimental Treatment 1 Intervention

Group III: Placebo Placebo Group 1 Intervention

Delta-8-THC is already approved in United States for the following indications:

Approved in United States as Delta-8-THC for:

• None officially approved; widely available due to hemp legalization but lacks formal approval for specific indications

Who Is Running the Clinical Trial?

University of Wisconsin, Madison

Lead Sponsor

Trials

1,249

Recruited

3,255,000+

Findings from Research

Dronabinol (medicinal THC) significantly impairs driving performance in both occasional and heavy cannabis users, with measurable increases in weaving (SDLP) and reaction time (TSA) after administration, indicating a dose-dependent effect.

Heavy users exhibited less driving impairment compared to occasional users, likely due to tolerance, while the Standard Field Sobriety Test failed to effectively identify clinically relevant impairment caused by dronabinol.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Medicinal Δ(9) -tetrahydrocannabinol (dronabinol) impairs on-the-road driving performance of occasional and heavy cannabis users but is not detected in Standard Field Sobriety Tests. Bosker, WM., Kuypers, KP., Theunissen, EL., et al.[2022]

In a pilot study of 58 subjects, delta 9-THC levels in hemolyzed blood peaked shortly after smoking and stabilized within an hour, reaching levels similar to those found in impaired drivers, indicating significant impairment potential.

Subjects exhibited an 'adaptation' effect, where their self-perception of impairment did not align with their actual performance on sobriety tests, suggesting that THC's effects may persist beyond measurable blood levels due to metabolites affecting the central nervous system.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Hemolyzed blood and serum levels of delta 9-THC: effects on the performance of roadside sobriety tests. Reeve, VC., Robertson, WB., Grant, J., et al.[2013]

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&#174; on simulated driving performance and co-monitoring of ocular activity: A randomised controlled trial. Manning, B., Hayley, AC., Catchlove, S., et al.[2023]

Acute use of tetrahydrocannabinol (THC) significantly impairs certain driving abilities, although the effects are generally modest, as shown by simulator and road course studies.

Factors such as dose, delivery method, and individual tolerance influence the level of impairment, while the role of cannabidiol in mitigating THC-induced impairment remains unclear and requires further research.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cannabis and driving ability. Sevigny, EL.[2022]

In a study involving 10 experienced marijuana smokers, oral Delta-9-tetrahydrocannabinol (Delta(9)-THC) was found to be chosen more often than a placebo, indicating some reinforcing effects, although participants selected it less than 50% of the time.

Both doses of Delta(9)-THC (10 mg and 20 mg) led to significant increases in positive subjective effects, impaired psychomotor performance, and increased heart rate, suggesting potential safety concerns alongside its therapeutic use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reinforcing effects of oral Delta9-THC in male marijuana smokers in a laboratory choice procedure. Hart, CL., Haney, M., Vosburg, SK., et al.[2022]

A survey of delta-8-THC consumers revealed that over half (51%) use it to treat various health conditions, with anxiety and stress being the most common, suggesting potential therapeutic benefits.

Participants reported favorably comparing delta-8-THC to delta-9-THC and pharmaceutical drugs, indicating it may have similar efficacy with potentially fewer adverse effects, although knowledge about safe dosages and medical integration remains low.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consumer Experiences with Delta-8-THC: Medical Use, Pharmaceutical Substitution, and Comparisons with Delta-9-THC. Kruger, DJ., Kruger, JS.[2023]

Delta-8-tetrahydrocannabinol (Δ8-THC) is widely available over-the-counter in the U.S. despite being classified as a Schedule I drug, leading to concerns about its legal status and safety due to unregulated sales.

The lack of regulation for Δ8-THC products has resulted in health risks, including medical emergencies from high-dose exposure, particularly in children, highlighting the urgent need for legislative action to ensure product safety and accurate labeling.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

&#916;8-THC: Legal Status, Widespread Availability, and Safety Concerns. Babalonis, S., Raup-Konsavage, WM., Akpunonu, PD., et al.[2022]

Delta(9)-tetrahydrocannabinol (Delta(9)-THC) has well-documented therapeutic benefits, including reducing nausea from chemotherapy, increasing appetite, alleviating pain, and relieving symptoms of multiple sclerosis, supported by extensive research over the past 30 years.

While Delta(9)-THC can impair cognitive functions such as memory and perception, and may induce negative psychological effects like panic and hallucinations, the long-term impacts are still unknown, leading to a proposal by WHO to reschedule it as a low-risk substance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The good and the bad effects of (-) trans-delta-9-tetrahydrocannabinol (Delta 9-THC) on humans. Carlini, EA.[2013]

A study involving 21 healthy adults found that tetrahydrocannabivarin (THCV) has a favorable safety profile, with most adverse events being mild and euphoric mood being the most common side effect.

Preliminary results suggest that certain doses of THCV (specifically 12.5, 25, and 200 mg) may improve sustained attention, although the effects were not consistently dose-dependent and higher doses led to THC-like effects, which could result in positive urine drug screens.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Two-Phase, Dose-Ranging, Placebo-Controlled Study of the Safety and Preliminary Test of Acute Effects of Oral &#916;8-Tetrahydrocannabivarin in Healthy Participants. Peters, EN., MacNair, L., Harrison, A., et al.[2023]

A review of 36 studies indicates that THC, the main psychoactive component of cannabis, significantly impairs psychomotor skills and cognitive functions, negatively affecting driving ability.

Drivers under the influence of cannabis are at a much higher risk of accidents, with studies showing that cannabis use can double or triple the likelihood of a crash, particularly when combined with alcohol.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neurocognitive Correlates in Driving Under the Influence of Cannabis. Busardò, FP., Pellegrini, M., Klein, J., et al.[2018]

A controlled study found that both medium (16.5 mg) and high doses (45.7 mg) of THC from hemp milk significantly impaired driving skills, with participants showing marked intoxication and reduced willingness to drive after consuming the highest dose.

The study revealed that the combined blood levels of THC and its active metabolite, 11-OH-THC, provided a better estimate of driving impairment than THC alone, indicating that both compounds should be considered when assessing the effects of cannabis on driving ability.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Assessment of driving capability through the use of clinical and psychomotor tests in relation to blood cannabinoids levels following oral administration of 20 mg dronabinol or of a cannabis decoction made with 20 or 60 mg Delta9-THC. Ménétrey, A., Augsburger, M., Favrat, B., et al.[2019]

In a study with 14 healthy volunteers, both THC-dominant and THC/CBD equivalent cannabis impaired driving performance, particularly increasing lane weaving, indicating that both types can negatively affect driving safety.

Interestingly, the THC/CBD equivalent cannabis led to higher peak plasma THC levels and caused greater impairment on certain cognitive tasks compared to THC-dominant cannabis, suggesting that CBD may not mitigate THC's adverse effects and could potentially worsen them.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition. Arkell, TR., Lintzeris, N., Kevin, RC., et al.[2022]

References

1. England pubmed.ncbi.nlm.nih.gov

Medicinal Δ(9) -tetrahydrocannabinol (dronabinol) impairs on-the-road driving performance of occasional and heavy cannabis users but is not detected in Standard Field Sobriety Tests. [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Hemolyzed blood and serum levels of delta 9-THC: effects on the performance of roadside sobriety tests. [2013]

3. United States pubmed.ncbi.nlm.nih.gov

Effect of CannEpil&#174; on simulated driving performance and co-monitoring of ocular activity: A randomised controlled trial. [2023]

4. Netherlands pubmed.ncbi.nlm.nih.gov

Cannabis and driving ability. [2022]

5. Germany pubmed.ncbi.nlm.nih.gov

Reinforcing effects of oral Delta9-THC in male marijuana smokers in a laboratory choice procedure. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Consumer Experiences with Delta-8-THC: Medical Use, Pharmaceutical Substitution, and Comparisons with Delta-9-THC. [2023]

7. United States pubmed.ncbi.nlm.nih.gov

&#916;8-THC: Legal Status, Widespread Availability, and Safety Concerns. [2022]

8. England pubmed.ncbi.nlm.nih.gov

The good and the bad effects of (-) trans-delta-9-tetrahydrocannabinol (Delta 9-THC) on humans. [2013]

9. United States pubmed.ncbi.nlm.nih.gov

A Two-Phase, Dose-Ranging, Placebo-Controlled Study of the Safety and Preliminary Test of Acute Effects of Oral &#916;8-Tetrahydrocannabivarin in Healthy Participants. [2023]

10. United Arab Emirates pubmed.ncbi.nlm.nih.gov

Neurocognitive Correlates in Driving Under the Influence of Cannabis. [2018]

11. England pubmed.ncbi.nlm.nih.gov

Assessment of driving capability through the use of clinical and psychomotor tests in relation to blood cannabinoids levels following oral administration of 20 mg dronabinol or of a cannabis decoction made with 20 or 60 mg Delta9-THC. [2019]

12. Germany pubmed.ncbi.nlm.nih.gov

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition. [2022]