The Impact of Oral Cannabis Administration and Co-Administration of Alcohol on Impairment

Browse trials for

• Alcoholic Intoxication 89

Study arms

• Placebo comparator
  Placebo cannabis + placebo alcohol

  Participants administer oral cannabis containing 0mg THC in combination with a placebo alcohol drink.

  Drug: Cannabis · Drug: Alcohol

• Experimental
  low dose cannabis with placebo alcohol

  Participants administer oral cannabis containing 10mg THC in combination with a placebo alcohol drink.

  Drug: Cannabis · Drug: Alcohol

• Experimental
  high dose cannabis with placebo alcohol

  Participants administer oral cannabis containing 25mg THC in combination with a placebo alcohol drink.

  Drug: Cannabis · Drug: Alcohol

• Experimental
  low dose cannabis with low dose alcohol

  Participants administer oral cannabis containing 10mg THC in combination with an alcohol drink (0.05 percent BAC).

  Drug: Cannabis · Drug: Alcohol

• Experimental
  high dose cannabis with low dose alcohol

  Participants administer oral cannabis containing 25mg THC in combination with an alcohol drink (0.05 percent BAC).

  Drug: Cannabis · Drug: Alcohol

• Experimental
  Placebo cannabis + low dose alcohol

  Participants administer oral cannabis containing 0mg THC in combination with an alcohol drink (0.05 percent BAC).

  Drug: Cannabis · Drug: Alcohol

• Experimental
  Placebo cannabis + high dose alcohol

  Participants administer oral cannabis containing 0mg THC in combination with an alcohol drink (0.08 percent BAC).

  Drug: Cannabis · Drug: Alcohol

Interventions

• DrugCannabis

  Cannabis will be orally ingested via a brownie

• DrugAlcohol

  Alcohol will be orally ingested via a flavored drink

Primary outcomes

1. Mean Peak Change From Baseline DRUID Application Global Impairment Score

   Acute cognitive and behavioral impairment will be assessed with global impairment score (range 0-100) on the DRUID app (higher scores indicate greater impairment). Results are mean change from baseline.

   Time frame: 7.5 hours, assessed at baseline (prior to drug administration) and again 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours after oral cannabis ingestion.

2. Cumulative Score on Field Sobriety Tests

   Impairment will be assessed using a battery of standard field sobriety tests including: the Horizontal Gaze Nystagmus Test (HGN), the Walk and Turn, the One Leg Stand, and the Modified Romberg Balance. We will report the cumulative amount of clues observed across these tasks (out of a possible 0-22 clues). Higher scores indicate greater/worse impairment. These assessments were completed once after 7.5 hours.

   Time frame: 7.5 hours

3. Mean Peak Change From Baseline Scores on the Drug Effect Questionnaire (DEQ) - Feel Drug Effect

   The DEQ will be used to obtain subjective ratings of "feel drug effects". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Results are mean change from baseline and a higher score indicates a more extreme/worse drug effect.

   Time frame: 7.5 hours, assessed at baseline (prior to drug administration) and again 0.5, 1, 1.25, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours after oral cannabis ingestion

4. Drug Effect Questionnaire - Feel High

   The DEQ will be used to obtain subjective ratings of "feel high". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Higher score greater "feel high" rating.

   Time frame: 7.5 hours

5. Drug Effect Questionnaire - Confidence to Drive (Change From Baseline)

   The DEQ will be used to obtain subjective ratings of "confidence to drive". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Higher scores indicate higher confidence to drive. Results expressed as change from baseline

   Time frame: 7.5 hours

6. Drug Effect Questionnaire - Willingness to Drive

   The DEQ will be used to obtain subjective ratings of "willingness to drive". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Higher score indicates higher willingness to drive.

   Time frame: 7.5 hours

7. Biphasic Alcohol Effects Scale (BAES) - Sedative Score

   The BAES is used to assess sedative and stimulant subjective effects of alcohol. There are 7 sedative-related questionnaire items, each presented on a scale of 0 (not at all) to 10 (extremely), which are integrated to produce an overall sedative score (0-70). Higher scores indicating greater sedative effects of alcohol. Scores presented show the change from baseline to 7.5 hours.

   Time frame: Baseline, 7.5 hours

8. Biphasic Alcohol Effects Scale (BAES) - Stimulant Score

   The BAES is used to assess sedative and stimulant subjective effects of alcohol. There are 7 stimulant-related questionnaire items, each presented on a scale of 0 (not at all) to 10 (extremely), which are integrated to produce an overall stimulant score (0-70). Higher scores indicating greater stimulant effects of alcohol.

   Time frame: 7.5 hours

9. Subjective High Assessment Scale (SHAS)

   For the SHAS, participants are presented with 13 questionnaire items, displayed on a visual analog scale anchored from 0 (normal) to 10 (extremely), which assess subjective effects of alcohol. These items are integrated to produce an overall SHAS score (0-130). Higher score indicates greater effects of alcohol.

   Time frame: 7.5 hours

10. Driving Performance as Assessed by Standard Deviation of Lateral Position (SDLP)

    The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. SDLP (measured in cm) was calculated across all drives to get a composite index of lateral control and reported as peak change from baseline. SDLP is the gold standard of quantifying the magnitude of driving impairment from drugs and alcohol and has excellent predictive validity to actual driving. Scores range from 0 to no upper limit. Higher scores represent higher magnitude of driving impairment.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

11. Driving Performance as Assessed by Composite Drive Score

    Driving impairment will be assessed via a composite drive score. The composite drive score is derived by integrating various driving outcomes (see primary and secondary driving outcomes). Higher z-score indicates worse performance. The score is on a z-score scale, meaning a score of 1 equates to 1 standard deviation outside of the participants' mean baseline performance and a Z-score of 0 represents the mean baseline performance. This was calculated across all drives and reported as peak change from baseline.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

Secondary outcomes

1. Driving Performance as Assessed by Standard Deviation of Speed (SDSP)

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. SDSP will be calculated across all drives to get a composite index of the variability in speed (measured in MPH) and is reported as peak change from baseline. Scores range from 0 to no upper limit. Higher scores represent higher magnitude of driving impairment.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

2. Total Run Length

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. Total run length will be calculated across all drives and measured as peak change from baseline score (in seconds). Higher scores represent higher magnitude of driving impairment.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

3. Driving Performance (Number of Speed Exceedances)

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. Driving performance will be calculated across all drives to get a cumulative number of times participants exceed the allowable speed limit and reported as peak change from baseline. Scores range from 0 to no upper limit. Higher scores represent higher numbers of speed exceedances.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

4. Driving Performance (Number of Accidents)

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. Driving performance will be calculated across all drives to get a cumulative number of accidents (including car collisions, pedestrians hit, etc.) and reported as peak change from baseline. Scores range from 0 to no upper limit. Higher scores represent higher numbers of accidents.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

5. Driving Performance (Total Rule Violations)

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. Driving performance will be calculated across all drives to get a cumulative number of total rule violations (including number of missed stop signs, illegal turns, speed exceedances, etc.) and reported as peak change from baseline. Scores range from 0 to no upper limit. Higher scores represent higher numbers of rule violations. All scores reported are relative to baseline, thus negative values represent a lower number of rule violations than at baseline.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

6. Driving Performance (Distance to Lead Vehicles)

   The STISIM Drive® M4000-R Console system will be used to assess driving performance, a state-of-the-art technology that has been independently validated to reflect real-world driving conditions. Driving performance will be calculated across all drives to get the mean distance (in meters) maintained to lead vehicles during car-following segments and reported as peak change from baseline. Scores range from 0 to no upper limit. Higher scores represent greater distance maintained to lead vehicles. All scores reported are relative to baseline, thus negative values represent a shorter distance maintained than at baseline.

   Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

7. Change in Field Sobriety Test - Score on Horizontal Gaze Nystagmus Test

   Impairment will be assessed using performance on the Horizontal Gaze Nystagmus Test (HGN). Total score will be recorded (out of possible 0-6 clues) with higher scores indicating higher impairment. Assessed at baseline and 7.5 hours, change from baseline to 7.5 hours reported

   Time frame: Baseline, 7.5 hours

8. Change in Field Sobriety Test - Score on Walk and Turn Test

   Impairment will be assessed using performance on the the Walk and Turn. Total score will be recorded (out of a possible 0-8 clues) with higher scores indicating higher impairment. Assessed at baseline and 7.5 hours, change from baseline to 7.5 hours reported

   Time frame: Baseline, 7.5 hours

9. Change in Field Sobriety Test - Score on One Leg Stand

   Impairment will be assessed using performance on the One Leg Stand test. Total score will be recorded (out of a possible 0-4 clues) with higher scores indicating higher impairment. Assessed at baseline and 7.5 hours, change from baseline to 7.5 hours reported

   Time frame: Baseline, 7.5 hours

10. Change in Field Sobriety Test - Score on Modified Romberg Balance

    Impairment will be assessed using performance on the Modified Romberg Balance test. Total score will be recorded (out of a possible 0-4 clues) with higher scores indicating higher impairment. Assessed at baseline and 7.5 hours, change from baseline to 7.5 hours reported

    Time frame: Baseline, 7.5 hours

11. Drug Effect Questionnaire - Like Drug Effect

    The DEQ will be used to obtain subjective ratings of "like drug effect". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Higher score indicating greater "liked drug effect" rating.

    Time frame: 7.5 hours

12. Drug Effect Questionnaire - Dislike Drug Effect

    The DEQ will be used to obtain subjective ratings of "dislike drug effect". Score range from 0 (none) to 100 (extreme) using a 100mm line anchored with none/extreme designation. Higher score indicating greater "dislike drug effect" rating.

    Time frame: 7.5 hours

13. Pharmacokinetics - CMax for THC and THC Metabolites

    Whole blood concentrations of THC, 11-OH-THC, and THCCOOH will be measured using quantitative liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis. The maximum concentration (Cmax) is determined as the highest concentration reached for each individual (ng/mL) across all timepoints.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

14. Pharmacokinetics - AUC for THC and THC Metabolites

    Whole blood concentrations of THC, 11-OH-THC, and THCCOOH will be measured using quantitative liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis. The area under the curve (AUC) is calculated cumulative across all timepoints.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

15. Pharmacokinetics - CMax for Alcohol

    BAC will be measured using the Alco-Sensor IV. Measuring BAC is needed to confirm that participants reached the targeted BAC for a given session and to confirm adherence to pre-session alcohol abstinence requirements (g/210L). The maximum concentration (Cmax) is determined as the highest concentration reached for each individual (ng/mL) across all timepoints.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

16. Pharmacokinetics - AUC for Alcohol

    Whole blood concentrations of Alcohol will be measured using quantitative liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis. The area under the curve (AUC) is calculated cumulative across all timepoints.

    Time frame: Baseline, 1, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 hours

Baseline characteristics

Publications

• Zamarripa CA, Lin S, Klausner M, Rastogi K, Roche DJO, Novak M, Antoine D, Wolinsky D, Marcotte TD, Weerts EM, Vandrey R, Spindle TR. Impact of Cannabis Edibles Combined With Alcohol on Driving, Field Sobriety Performance, and Subjective Effects: A Within-Participant Crossover Trial. JAMA Netw Open. 2026 May 1;9(5):e269842. doi: 10.1001/jamanetworkopen.2026.9842. PubMed 42065887 ↗

Study documents

• Protocol and statistical analysis plan · Oct 9, 2025

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: No