High Confusion: Cannabis & Driving

October 9, 2025 updated by: University of Wisconsin, Madison

High Confusion: Evaluating Effects of Popular Cannabis Isolates on Driving Performance

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

5

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Wisconsin
      • Madison, Wisconsin, United States, 53792
        • University of Wisconsin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • At least 18 years of age, no older than 49 years of age
  • 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
  • In possession of a valid drivers' license with at least two years of driving experience
  • English-speaking (able to provide consent and complete questionnaires)
  • Written Informed Consent

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)
  • Use of medications that may impact driving ability (e.g., mood stabilizers, sedatives)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Drug: Placebo
Healthy volunteers will attend three test sessions, at least 14 days apart, in which cognition and driving performance will be assessed following vaporization of (1) Δ9-THC, (2) Δ8-THC, or (3) a placebo. The order of these conditions will be counterbalanced across participants. Serial blood samples will be drawn during each dosing visit and compared with concurrent dried blood spots from a finger stick.
Experimental: delta-9-THC
Drug: Delta-9-THC
Healthy volunteers will attend three test sessions, at least 14 days apart, in which cognition and driving performance will be assessed following vaporization of (1) Δ9-THC, (2) Δ8-THC, or (3) a placebo. The order of these conditions will be counterbalanced across participants. Serial blood samples will be drawn during each dosing visit and compared with concurrent dried blood spots from a finger stick.
Experimental: delta-8-THC
Drug: Delta-8-THC
Healthy volunteers will attend three test sessions, at least 14 days apart, in which cognition and driving performance will be assessed following vaporization of (1) Δ9-THC, (2) Δ8-THC, or (3) a placebo. The order of these conditions will be counterbalanced across participants. Serial blood samples will be drawn during each dosing visit and compared with concurrent dried blood spots from a finger stick.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Quantify analyte concentrations
Time Frame: 9 months
Quantify delta-9-THC, delta-8-THC, and their primary metabolites in whole blood, plasma, oral fluid, and dried blood spots at several time points before and after acute study drug administration.
9 months
Quantify impairing effects of cannabinoids
Time Frame: 9 months
Quantify the impairing effects of delta-9-THC and delta-8-THC by measuring the standard deviation of lateral position within the driving simulation and by completing a drug recognition expert field sobriety test for signs of impairment.
9 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Wisconsin, Madison

Investigators

  • Principal Investigator: Heather Barkholtz, PhD, University of Wisconsin, Madison

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 25, 2025

Primary Completion (Actual)

September 16, 2025

Study Completion (Actual)

September 16, 2025

Study Registration Dates

First Submitted

January 16, 2024

First Submitted That Met QC Criteria

January 24, 2024

First Posted (Actual)

February 1, 2024

Study Record Updates

Last Update Posted (Estimated)

October 10, 2025

Last Update Submitted That Met QC Criteria

October 9, 2025

Last Verified

October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2022-1124
  • A523000 (Other Identifier: UW Madison)
  • Protocol Version 2/5/2025 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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