Cannabis IntoxicationPhase 1/2NCT02849587
The Impact and Detection of Driving Impairments Associated With Acute Cannabis Smoking
A Phase 1/2 study testing Cannabis in people with Cannabis Intoxication, run by University of California, San Diego at 1 site in United States.
Trial summary
This study was authorized by the California Legislature (Assembly Bill 266, the Medical Marijuana Regulation and Safety Act to help with detection of driving under the influence of cannabis. Read more about this study
- Who is it for?
- Ages 21 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Cannabis Intoxication
- What is being tested?
- Cannabis
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 199 participants
- Where
- 1 siteUnited States
- Study dates
- 24 Feb 2017to 17 Jun 2019
- Phase
- Phase 1/2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Be a licensed driver.
- Need to have acuity of 20/40 or better, with or without correction on a Snellen Visual Acuity eye chart.
Who cannot join
- At the discretion of the examining physician, individuals with significant cardiovascular, hepatic or renal disease, uncontrolled hypertension, and chronic pulmonary disease (eg, asthma, COPD) will be excluded.
- Unwillingness to abstain from cannabis for 2 days prior to screening and experimental visits
- Positive pregnancy test
- A positive result on toxicity screening for cocaine, amphetamines, opiates, and phencyclidine (PCP) will exclude individuals from participation.
- Unwilling to refrain from driving or operating heavy machinery for four hours after consuming study medication.
Trial locations and contacts
1 site in 1 country.
United States1 site
Center for Medicinal Cannabis Research, UC San Diego
San Diego, California, 92103
About this study
Official title: A Randomized, Controlled Trial of Cannabis in Healthy Volunteers Evaluating Simulated Driving, Field Performance Tests and Cannabinoid Levels
This study was authorized by the California Legislature (Assembly Bill 266, the Medical Marijuana Regulation and Safety Act to help with detection of driving under the influence of cannabis. One hundred and eighty healthy volunteers will inhale smoked cannabis with either 0% (placebo), 5.9%, or 13.4% Δ9-tetrahydrocannabinol (THC) at the beginning of the day, and then complete driving simulations, iPad-based performance assessments, and bodily fluid draws (e.g., blood, saliva, breath) before the cannabis smoking and a number of times over the subsequent 6 hours after cannabis smoking. The purpose is to determine (1) the relationship of the dose of Δ9-THC on driving performance and (2) the duration of driving impairment in terms of hours from initial use, (3) if saliva or expired air can serve as a useful substitute for blood sampling of Δ9-THC, and (4) if testing using an iPad can serve as a useful adjunct to the standardized field sobriety test in identifying acute impairment from cannabis.
Read the detailed description
There are several studies that suggest higher doses of whole-blood Δ9-tetrahydrocannabinol (Δ9-THC) concentration are associated with increased crash risk and crash culpability. However, attempts to define a cut-off point for blood Δ9-THC levels have proven to be challenging. Unlike alcohol, for which a level can be reasonably measured using a breathalyzer (and confirmed with a blood test), detection of a cut-off point for intoxication related to Δ9-THC concentration has eluded scientific verification. Recent evidence suggests blood Δ9-THC concentrations of 2-5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Others have countered that this level leads to false positives, particularly in heavy cannabis users inasmuch as THC may be detectable in their blood specimens for 12-24 hours after inhalation. Given that 12 to 24 hours is beyond the likely period of driving impairment, this would appear to be a justifiable objection to a per se cut-off point for a Δ9-THC concentration indicative of impairment. Maximal driving impairment is found 20 to 40 minutes after smoking, and the risk of driving impairment decreases over the following hours, at least in those who smoke 18 mg Δ9-THC or less, the dose often used experimentally to duplicate a single joint. Other studies, however, report residual motor vehicle accident crash risk when cannabis is used within 4 hours prior to driving.
The roadside examination using the Standardized Field Sobriety Test (SFST) for proof of cannabis-related impairment has not been an ideal alternative to blood levels. Originally devised to evaluate impairment under the influence of alcohol, the SFST is comprised of three examinations administered in a standardized manner by law enforcement officers. The 'Horizontal Gaze Nystagmus' (HGN), the 'One Leg Stand' (OLS) and the 'Walk and Turn' test (WAT) require a person to follow instructions and perform motor activities. During the assessments, officers observe and record signs of impairment. In one study, Δ9-THC produced impairments on overall SFST performance in 50 % of the participants. In a separate study involving acute administration of cannabis, 30% of people failed the SFST. This discrepancy was thought to be in part due to the participant's cannabis use history, as well as low percentage of THC in the cannabis. The reported frequency of cannabis use varied from once a week to once every 2-6 months in the study where there was a failure on the SFST by 50% of the participants. The other study included more frequent users who smoked cannabis on at least four occasions per week.
Based upon the above, another means is needed to help law enforcement officers discern driving under the influence of cannabis. One future possibility is the development of performance-based measures of cannabis-related impairments. This will include testing of critical tracking, time estimation, balance and visual spatial learning. The investigators have selected brief measures in order to be practicably administered repeatedly over a short time period, as well as tests that have the potential to translate to a field-feasible tablet-based format, should there be benefit in possibly including these in future performance-based measures for use in the field by law enforcement officers (e.g., a cannabis-focused field sobriety test).
- Conditions
- Cannabis Intoxication
- Being tested
- Cannabis
- Keywords
- Driving Under the Influence, Memory Impairment, Reaction Time, Time Perception, Cannabis, Marijuana, Whole Blood, Oral Fluid, Breath, Driving simulator
- Medical subject headings
- Driving Under the Influence, Memory Disorders, Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CannabisDrug
Also called Marijuana
Participants will smoke a cannabis cigarette ad libitum as per their usual routine
| Study group | Role | What they receive |
|---|---|---|
| Placebo Cannabis | Placebo comparator | Subjects will smoke cannabis with placebo THC (.02%) ad libitum Receives: Drug: Cannabis |
| Cannabis with 5.9% THC | Experimental | Subjects will smoke cannabis cigarettes with 5.9% THC ad libitum Receives: Drug: Cannabis |
| Cannabis with 13.4% THC | Experimental | Subjects will smoke cannabis cigarettes with 13.4% THC ad libitum Receives: Drug: Cannabis |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Composite Drive Score (CDS) From Pre-smoking Simulation
The Composite Drive Score (CDS) is a z-score comprised of key variables from the simulator tasks (SDLP, speed deviation, and task accuracy during the modified Surrogate Reference Task (mSuRT); coherence from the car following task). This outcome reflects the change in CDS from the pre-smoking assessment, at each timepoint.
The z-score indicates the number of standard deviations away from the mean from the baseline performance for the entire group (n = 191). A Z-score of 0 is equal to the mean of a reference population (in this case the pre-smoking performance for the entire group).
Higher z-scores at each timepoint indicate worse performance (variables that went in the opposite direction were reflected in order to have all variables have the same direction). When examining the change in Composite Drive Score (this outcome variable), a higher score indicates a decline in performance (e.g., Time 2 minus Time 1).
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Secondary outcomes (13)
Simulator: Standard Deviation of Lateral Position (SDLP)
This measures the standard deviation of lateral (lane) position, or the degree to which the participant "swerves" within the road lane on the driving simulation during the modified Surrogate Reference Task (mSuRT). The range is from .39 to 3.33. A higher score indicates worse performance.
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Speed Deviation
The variability in speed during the modified Surrogate Reference Test (mSuRT). The speed is in miles per hour. Range is from .17 to 12.85. A higher score indicates worse performance.
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Correct Hits on mSuRT
The number of times the participant touched the correct stimulus (circle) on the iPad, during modified Surrogate Reference Task (mSuRT). Range is from 8 to 32. A higher score is a better score.
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Car Following - Coherence
Coherence is the correlation (0 to 1) between the participant and the lead car (which speeds up and slows down), representing the participant's ability to accurately speed up and slow down similarly to the lead car. Range of scores is from .01 to .97. A higher score is a better score.
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Response Delay - Car Following
Time delay (in seconds) in responding to changes in the lead car's speed. Range is from -5.8 to 6.0. A higher score indicates a worse score.
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Distance From Lead Car - Car Following
The outcome is distance from the lead car (in virtual feet) during the Car Following Task
Measured: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Tablet Assessment: Dual Attention Missed Switches
The participant follows a moving target (square) with her/his finger, and switches to following a new stimulus when it appears in the corner of the screen. Each participant was classified as to whether he/she missed any of these switches during the trial. The outcome is the proportion of participants within each group who missed at least one switch. The range is from 0 to 1. Higher indicates a worse score.
Measured: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Lane Tracking Standard Deviation
The participant is to rotate the iPad in order to keep a round object in the center, between two lines (lanes). This measure is the standard deviation of the position of the round object during the task (in essence, how much "swerving" there is within the lane). The range is from 8.2 to 189.4. A higher score indicates worse performance.
Measured: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Visual Spatial Learning Test Number Correct
Assessment of short-term memory for abstract figures. The participant is to memorize abstract figures and their locations on a 3 x 3 grid. After initial viewing (10 seconds), the figures go away for either 4, 12, or 24 seconds. The participant is then to identify which figures were in the initial viewing (from a list at the bottom of the screen), and place them at the correct location. This is the number of correctly identified figures. The range is from 0 to 12. A higher score indicates better performance.
Measured: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Time Estimation
The participant is to estimate the amount of time that has passed while performing a secondary task. This outcome is the ratio of 1) the estimated time that has passed (seconds), divided by 2) the actual amount of time that has passed. The range is from 0.204 to 1.89. A higher score indicates a better performance.
Measured: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Balance
While standing and keeping their feet still, this is a measure of the participant's "sway", which is the total distance that the participant's body moved (in meters) from his/her initial vertical position. This was measured using an accelerometer placed on the participant's back. The range of scores is from .222 to 1.661. A higher score indicates worse performance.
Measured: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
THC Concentrations: Correlation Between Blood and Oral Fluid
Spearman's correlation between THC concentrations in whole blood and oral fluid. Higher scores are better.
Measured: Approximately 15 minutes post-smoking
THC Concentrations: Correlation Between Whole Blood and Breath
Spearman's correlation between THC concentrations in whole blood and breath
Measured: Approximately 15 minutes post-smoking
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jul 2016 (estimated)
- Study start24 Feb 2017
- Primary completion17 Jun 2019
- Study completion17 Jun 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (12)Papers the sponsor has linked to this study.
- Other trials for Cannabis IntoxicationStudies of the same condition, open and under way.
- More trials run by University of California, San DiegoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Screening
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomized to smoke a cannabis cigarette containing placebo (.02%), 5.9% or 13.4% THC.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 199 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, San Diego
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Thomas D. Marcotte, PhD, University of California, San Diego
- Investigators
- Thomas D Marcotte, PhD, Principal investigator, University of California, San Diego
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02849587
- Sponsor's protocol ID
- 160641
- Status last verified
- Dec 2021
- First submitted
- 14 Jul 2016
- Last updated
- 4 Jan 2022
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data to facilitate meta-analyses
Publications
Hartman RL, Huestis MA. Cannabis effects on driving skills. Clin Chem. 2013 Mar;59(3):478-92. doi: 10.1373/clinchem.2012.194381. Epub 2012 Dec 7.
PubMed 23220273Papafotiou K, Carter JD, Stough C. An evaluation of the sensitivity of the Standardised Field Sobriety Tests (SFSTs) to detect impairment due to marijuana intoxication. Psychopharmacology (Berl). 2005 Jun;180(1):107-14. doi: 10.1007/s00213-004-2119-9. Epub 2004 Dec 24.
PubMed 15619106Fabritius M, Chtioui H, Battistella G, Annoni JM, Dao K, Favrat B, Fornari E, Lauer E, Maeder P, Giroud C. Comparison of cannabinoid concentrations in oral fluid and whole blood between occasional and regular cannabis smokers prior to and after smoking a cannabis joint. Anal Bioanal Chem. 2013 Dec;405(30):9791-803. doi: 10.1007/s00216-013-7412-1. Epub 2013 Nov 8.
PubMed 24202191Beck O, Stephanson N, Sandqvist S, Franck J. Detection of drugs of abuse in exhaled breath from users following recovery from intoxication. J Anal Toxicol. 2012 Nov-Dec;36(9):638-46. doi: 10.1093/jat/bks079. Epub 2012 Oct 7.
PubMed 23045289Marcotte TD, Heaton RK, Wolfson T, Taylor MJ, Alhassoon O, Arfaa K, Ellis RJ, Grant I. The impact of HIV-related neuropsychological dysfunction on driving behavior. The HNRC Group. J Int Neuropsychol Soc. 1999 Nov;5(7):579-92. doi: 10.1017/s1355617799577011.
PubMed 10645701Marcotte TD, Rosenthal TJ, Roberts E, Lampinen S, Scott JC, Allen RW, Corey-Bloom J. The contribution of cognition and spasticity to driving performance in multiple sclerosis. Arch Phys Med Rehabil. 2008 Sep;89(9):1753-8. doi: 10.1016/j.apmr.2007.12.049.
PubMed 18760160Hubbard JA, Hoffman MA, Ellis SE, Sobolesky PM, Smith BE, Suhandynata RT, Sones EG, Sanford SK, Umlauf A, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Biomarkers of Recent Cannabis Use in Blood, Oral Fluid and Breath. J Anal Toxicol. 2021 Sep 17;45(8):820-828. doi: 10.1093/jat/bkab080.
PubMed 34185831Hoffman MA, Hubbard JA, Sobolesky PM, Smith BE, Suhandynata RT, Sanford S, Sones EG, Ellis S, Umlauf A, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Blood and Oral Fluid Cannabinoid Profiles of Frequent and Occasional Cannabis Smokers. J Anal Toxicol. 2021 Sep 17;45(8):851-862. doi: 10.1093/jat/bkab078.
PubMed 34173005Hubbard JA, Smith BE, Sobolesky PM, Kim S, Hoffman MA, Stone J, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to detect cannabinoids in whole blood and breath. Clin Chem Lab Med. 2020 Apr 28;58(5):673-681. doi: 10.1515/cclm-2019-0600.
PubMed 31527291Sobolesky PM, Smith BE, Hubbard JA, Stone J, Marcotte TD, Grelotti DJ, Grant I, Fitzgerald RL. Validation of a liquid chromatography-tandem mass spectrometry method for analyzing cannabinoids in oral fluid. Clin Chim Acta. 2019 Apr;491:30-38. doi: 10.1016/j.cca.2019.01.002. Epub 2019 Jan 4.
PubMed 30615854Marcotte TD, Umlauf A, Grelotti DJ, Sones EG, Mastropietro KF, Suhandynata RT, Huestis MA, Grant I, Fitzgerald RL. Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis: A Randomized Clinical Trial. JAMA Psychiatry. 2023 Sep 1;80(9):914-923. doi: 10.1001/jamapsychiatry.2023.2345.
PubMed 37531115Marcotte TD, Umlauf A, Grelotti DJ, Sones EG, Sobolesky PM, Smith BE, Hoffman MA, Hubbard JA, Severson J, Huestis MA, Grant I, Fitzgerald RL. Driving Performance and Cannabis Users' Perception of Safety: A Randomized Clinical Trial. JAMA Psychiatry. 2022 Mar 1;79(3):201-209. doi: 10.1001/jamapsychiatry.2021.4037.
PubMed 35080588
Study at a glance
From the registry record, last updated by the sponsor on 4 Jan 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Controlled Trial of Cannabis in Healthy Volunteers Evaluating Simulated Driving, Field Performance Tests and Cannabinoid Levels
- ClinicalTrials.gov ID
- NCT02849587
- Acronym / sponsor ID
- 160641
- Conditions
- Cannabis Intoxication
- Keywords
- Driving Under the Influence, Memory Impairment, Reaction Time, Time Perception, Cannabis, Marijuana, Whole Blood, Oral Fluid
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 199 participants (actual)
- Lead sponsor
- University of California, San DiegoUniversity, hospital or other
- Study start
- 24 Feb 2017 (actual)
- Primary completion
- 17 Jun 2019 (actual)
- Study completion
- 17 Jun 2019 (actual)
- First posted
- 29 Jul 2016 (estimated)
- Results
- Posted 4 Jan 2022
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study was authorized by the California Legislature (Assembly Bill 266, the Medical Marijuana Regulation and Safety Act to help with detection of driving under the influence of cannabis. One hundred and eighty healthy volunteers will inhale smoked cannabis with either 0% (placebo), 5.9%, or 13.4% Δ9-tetrahydrocannabinol (THC) at the beginning of the day, and then complete driving simulations, iPad-based performance assessments, and bodily fluid draws (e.g., blood, saliva, breath) before the cannabis smoking and a number of times over the subsequent 6 hours after cannabis smoking. The purpose is to determine (1) the relationship of the dose of Δ9-THC on driving performance and (2) the duration of driving impairment in terms of hours from initial use, (3) if saliva or expired air can serve as a useful substitute for blood sampling of Δ9-THC, and (4) if testing using an iPad can serve as a useful adjunct to the standardized field sobriety test in identifying acute impairment from cannabis.
Detailed description
There are several studies that suggest higher doses of whole-blood Δ9-tetrahydrocannabinol (Δ9-THC) concentration are associated with increased crash risk and crash culpability. However, attempts to define a cut-off point for blood Δ9-THC levels have proven to be challenging. Unlike alcohol, for which a level can be reasonably measured using a breathalyzer (and confirmed with a blood test), detection of a cut-off point for intoxication related to Δ9-THC concentration has eluded scientific verification. Recent evidence suggests blood Δ9-THC concentrations of 2-5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Others have countered that this level leads to false positives, particularly in heavy cannabis users inasmuch as THC may be detectable in their blood specimens for 12-24 hours after inhalation. Given that 12 to 24 hours is beyond the likely period of driving impairment, this would appear to be a justifiable objection to a per se cut-off point for a Δ9-THC concentration indicative of impairment. Maximal driving impairment is found 20 to 40 minutes after smoking, and the risk of driving impairment decreases over the following hours, at least in those who smoke 18 mg Δ9-THC or less, the dose often used experimentally to duplicate a single joint. Other studies, however, report residual motor vehicle accident crash risk when cannabis is used within 4 hours prior to driving.
The roadside examination using the Standardized Field Sobriety Test (SFST) for proof of cannabis-related impairment has not been an ideal alternative to blood levels. Originally devised to evaluate impairment under the influence of alcohol, the SFST is comprised of three examinations administered in a standardized manner by law enforcement officers. The 'Horizontal Gaze Nystagmus' (HGN), the 'One Leg Stand' (OLS) and the 'Walk and Turn' test (WAT) require a person to follow instructions and perform motor activities. During the assessments, officers observe and record signs of impairment. In one study, Δ9-THC produced impairments on overall SFST performance in 50 % of the participants. In a separate study involving acute administration of cannabis, 30% of people failed the SFST. This discrepancy was thought to be in part due to the participant's cannabis use history, as well as low percentage of THC in the cannabis. The reported frequency of cannabis use varied from once a week to once every 2-6 months in the study where there was a failure on the SFST by 50% of the participants. The other study included more frequent users who smoked cannabis on at least four occasions per week.
Based upon the above, another means is needed to help law enforcement officers discern driving under the influence of cannabis. One future possibility is the development of performance-based measures of cannabis-related impairments. This will include testing of critical tracking, time estimation, balance and visual spatial learning. The investigators have selected brief measures in order to be practicably administered repeatedly over a short time period, as well as tests that have the potential to translate to a field-feasible tablet-based format, should there be benefit in possibly including these in future performance-based measures for use in the field by law enforcement officers (e.g., a cannabis-focused field sobriety test).
Study design
- Primary purpose
- Screening
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- Participants will be randomized to smoke a cannabis cigarette containing placebo (.02%), 5.9% or 13.4% THC.
| Arm | Type | Receives |
|---|---|---|
| Placebo Cannabis | Placebo comparator | Drug: CannabisSubjects will smoke cannabis with placebo THC (.02%) ad libitum |
| Cannabis with 5.9% THC | Experimental | Drug: CannabisSubjects will smoke cannabis cigarettes with 5.9% THC ad libitum |
| Cannabis with 13.4% THC | Experimental | Drug: CannabisSubjects will smoke cannabis cigarettes with 13.4% THC ad libitum |
Who may qualify
- Ages
- 21 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Be a licensed driver.
- Need to have acuity of 20/40 or better, with or without correction on a Snellen Visual Acuity eye chart.
Key exclusion criteria (5 listed)
- At the discretion of the examining physician, individuals with significant cardiovascular, hepatic or renal disease, uncontrolled hypertension, and chronic pulmonary disease (eg, asthma, COPD) will be excluded.
- Unwillingness to abstain from cannabis for 2 days prior to screening and experimental visits
- Positive pregnancy test
- A positive result on toxicity screening for cocaine, amphetamines, opiates, and phencyclidine (PCP) will exclude individuals from participation.
- Unwilling to refrain from driving or operating heavy machinery for four hours after consuming study medication.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CannabisAlso: MarijuanaParticipants will smoke a cannabis cigarette ad libitum as per their usual routine | Drug | Cannabis with 13.4% THC, Cannabis with 5.9% THC, Placebo Cannabis |
Primary outcome
Change in Composite Drive Score (CDS) From Pre-smoking Simulation
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
The Composite Drive Score (CDS) is a z-score comprised of key variables from the simulator tasks (SDLP, speed deviation, and task accuracy during the modified Surrogate Reference Task (mSuRT); coherence from the car following task). This outcome reflects the change in CDS from the pre-smoking assessment, at each timepoint. The z-score indicates the number of standard deviations away from the mean from the baseline performance for the entire group (n = 191). A Z-score of 0 is equal to the mean of a reference population (in this case the pre-smoking performance for the entire group). Higher z-scores at each timepoint indicate worse performance (variables that went in the opposite direction were reflected in order to have all variables have the same direction). When examining the change in Composite Drive Score (this outcome variable), a higher score indicates a decline in performance (e.g., Time 2 minus Time 1).
13 secondary outcomes
Simulator: Standard Deviation of Lateral Position (SDLP)
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Speed Deviation
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Correct Hits on mSuRT
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Car Following - Coherence
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Response Delay - Car Following
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Simulator: Distance From Lead Car - Car Following
Time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking
Tablet Assessment: Dual Attention Missed Switches
Time frame: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Lane Tracking Standard Deviation
Time frame: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Visual Spatial Learning Test Number Correct
Time frame: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Time Estimation
Time frame: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
Tablet Assessment: Balance
Time frame: Participants assessed pre-smoking and 1 hour, 2 hours, 4 hours, and 5 hours after smoking
THC Concentrations: Correlation Between Blood and Oral Fluid
Time frame: Approximately 15 minutes post-smoking
THC Concentrations: Correlation Between Whole Blood and Breath
Time frame: Approximately 15 minutes post-smoking
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Jan 2022.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 23220273Hartman RL, Huestis MA. Cannabis effects on driving skills. Clin Chem. 2013 Mar;59(3):478-92. doi: 10.1373/clinchem.2012.194381. Epub 2012 Dec 7.
- Background: PubMed 15619106Papafotiou K, Carter JD, Stough C. An evaluation of the sensitivity of the Standardised Field Sobriety Tests (SFSTs) to detect impairment due to marijuana intoxication. Psychopharmacology (Berl). 2005 Jun;180(1):107-14. doi: 10.1007/s00213-004-2119-9. Epub 2004 Dec 24.
- Background: PubMed 24202191Fabritius M, Chtioui H, Battistella G, Annoni JM, Dao K, Favrat B, Fornari E, Lauer E, Maeder P, Giroud C. Comparison of cannabinoid concentrations in oral fluid and whole blood between occasional and regular cannabis smokers prior to and after smoking a cannabis joint. Anal Bioanal Chem. 2013 Dec;405(30):9791-803. doi: 10.1007/s00216-013-7412-1. Epub 2013 Nov 8.
- Background: PubMed 23045289Beck O, Stephanson N, Sandqvist S, Franck J. Detection of drugs of abuse in exhaled breath from users following recovery from intoxication. J Anal Toxicol. 2012 Nov-Dec;36(9):638-46. doi: 10.1093/jat/bks079. Epub 2012 Oct 7.
- Background: PubMed 10645701Marcotte TD, Heaton RK, Wolfson T, Taylor MJ, Alhassoon O, Arfaa K, Ellis RJ, Grant I. The impact of HIV-related neuropsychological dysfunction on driving behavior. The HNRC Group. J Int Neuropsychol Soc. 1999 Nov;5(7):579-92. doi: 10.1017/s1355617799577011.
- Background: PubMed 18760160Marcotte TD, Rosenthal TJ, Roberts E, Lampinen S, Scott JC, Allen RW, Corey-Bloom J. The contribution of cognition and spasticity to driving performance in multiple sclerosis. Arch Phys Med Rehabil. 2008 Sep;89(9):1753-8. doi: 10.1016/j.apmr.2007.12.049.
- Results publication: PubMed 34185831Hubbard JA, Hoffman MA, Ellis SE, Sobolesky PM, Smith BE, Suhandynata RT, Sones EG, Sanford SK, Umlauf A, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Biomarkers of Recent Cannabis Use in Blood, Oral Fluid and Breath. J Anal Toxicol. 2021 Sep 17;45(8):820-828. doi: 10.1093/jat/bkab080.
- Results publication: PubMed 34173005Hoffman MA, Hubbard JA, Sobolesky PM, Smith BE, Suhandynata RT, Sanford S, Sones EG, Ellis S, Umlauf A, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Blood and Oral Fluid Cannabinoid Profiles of Frequent and Occasional Cannabis Smokers. J Anal Toxicol. 2021 Sep 17;45(8):851-862. doi: 10.1093/jat/bkab078.
- Results publication: PubMed 31527291Hubbard JA, Smith BE, Sobolesky PM, Kim S, Hoffman MA, Stone J, Huestis MA, Grelotti DJ, Grant I, Marcotte TD, Fitzgerald RL. Validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to detect cannabinoids in whole blood and breath. Clin Chem Lab Med. 2020 Apr 28;58(5):673-681. doi: 10.1515/cclm-2019-0600.
- Results publication: PubMed 30615854Sobolesky PM, Smith BE, Hubbard JA, Stone J, Marcotte TD, Grelotti DJ, Grant I, Fitzgerald RL. Validation of a liquid chromatography-tandem mass spectrometry method for analyzing cannabinoids in oral fluid. Clin Chim Acta. 2019 Apr;491:30-38. doi: 10.1016/j.cca.2019.01.002. Epub 2019 Jan 4.
- Derived from this study: PubMed 37531115Marcotte TD, Umlauf A, Grelotti DJ, Sones EG, Mastropietro KF, Suhandynata RT, Huestis MA, Grant I, Fitzgerald RL. Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis: A Randomized Clinical Trial. JAMA Psychiatry. 2023 Sep 1;80(9):914-923. doi: 10.1001/jamapsychiatry.2023.2345.
- Derived from this study: PubMed 35080588Marcotte TD, Umlauf A, Grelotti DJ, Sones EG, Sobolesky PM, Smith BE, Hoffman MA, Hubbard JA, Severson J, Huestis MA, Grant I, Fitzgerald RL. Driving Performance and Cannabis Users' Perception of Safety: A Randomized Clinical Trial. JAMA Psychiatry. 2022 Mar 1;79(3):201-209. doi: 10.1001/jamapsychiatry.2021.4037.
- Center for Medicinal Cannabis Research, UC San DiegoLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Data to facilitate meta-analyses
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Thomas D Marcotte, PhD principal investigator
University of California, San Diego
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Cannabis in people with Cannabis Intoxication, run by University of California, San Diego at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Jan 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 4 Jan 2022). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Composite Drive Score (CDS) From Pre-smoking Simulation (time frame: Participants are assessed pre-smoking, and then approximately 30m, 1h 30m, 3h 30m and 4h 30m post-smoking). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02849587, which also lists 12 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Jan 2022.