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Brown T, Kruse C, Schmitt R, Gaffney G, Milavetz G. Assessing the impact of cannabis use on freeway driving performance and practices: A comparative analysis with placebo and alcohol-influenced driving. TRAFFIC INJURY PREVENTION 2024:1-10. [PMID: 39303060 DOI: 10.1080/15389588.2024.2393215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2024] [Revised: 08/12/2024] [Accepted: 08/12/2024] [Indexed: 09/22/2024]
Abstract
OBJECTIVE The objectives of this study were 1) to identify the effects cannabis has on driving performance and individual motor practices when on the freeway compared to placebo and 2) to bring context to the effects of cannabis on driving by comparing effect sizes to those of alcohol. METHODS Data for analysis was collected from a study of fifty-three participants with a history of tetrahydrocannabinol (THC) cannabis use who completed three visits in randomized order (placebo (0% THC), 6.18% THC, and 10.5% THC). Data for the alcohol analysis was from a subset of eighteen of these participants with a history of recent alcohol use that completed a fourth alcohol visit that targeted a .05 g/210L breath alcohol content (BrAC) during the drive. Comparisons were made using an analysis of variance approach with the SAS General Linear Models Procedure. Cohen's d effect sizes were calculated for the cannabis and alcohol conditions relative to placebo for both the full sample and alcohol subset. RESULTS Standard deviation of lane position (SDLP) for cannabis significantly increased compared to placebo and the effect size was comparable to that of alcohol at .05 BrAC. Lane departures for cannabis significantly increased relative to placebo as did the time out of the lane. Cannabis use resulted in an increased amount of time at 10% or more below the speed limit for the 6.18% THC condition. Relative to alcohol, cannabis produced more time at slower speeds and less time at speeds more than 10% above the speed limit. CONCLUSIONS Multiple factors of lateral and longitudinal vehicle control on the freeway showed statistical significance. Drivers under the influence of cannabis exhibited higher rates of driving errors but also showed more cautious behaviors such as generally lower speeds on the freeway. Compared with alcohol, effect sizes varied. For longitudinal control, there were larger effect sizes for alcohol with speed effects in opposite directions, but relatively equivalent effect sizes for lateral control and driving errors associated with lane keeping.
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Affiliation(s)
- Timothy Brown
- University of Iowa Driving Safety Research Institute, Iowa City, Iowa
| | - Cole Kruse
- College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa
| | - Rose Schmitt
- University of Iowa Driving Safety Research Institute, Iowa City, Iowa
| | - Gary Gaffney
- University of Iowa Driving Safety Research Institute, Iowa City, Iowa
| | - Gary Milavetz
- College of Pharmacy, University of Iowa, Iowa City, Iowa
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Zhao S, Brands B, Kaduri P, Wickens CM, Hasan OSM, Chen S, Le Foll B, Di Ciano P. The effect of cannabis edibles on driving and blood THC. J Cannabis Res 2024; 6:26. [PMID: 38822413 PMCID: PMC11140993 DOI: 10.1186/s42238-024-00234-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 04/16/2024] [Indexed: 06/03/2024] Open
Abstract
BACKGROUND Cannabis has been shown to impact driving due to changes produced by delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis. Current legal thresholds for blood THC while driving are based predominantly on evidence utilizing smoked cannabis. It is known that levels of THC in blood are lower after eating cannabis as compared to smoking yet the impact of edibles on driving and associated blood THC has never been studied. METHODS Participants drove a driving simulator before and after ingesting their preferred legally purchased cannabis edible. In a counterbalanced control session, participants did not consume any THC or cannabidiol (CBD). Blood was collected for measurement of THC and metabolites as well as CBD. Subjective experience was also assessed. RESULTS Participants consumed edibles with, on average, 7.3 mg of THC, which is less than the maximum amount available in a single retail package in Ontario, providing an ecologically valid test of cannabis edibles. Compared to control, cannabis edibles produced a decrease in mean speed 2 h after consumption but not at 4 and 6 h. Under dual task conditions in which participants completed a secondary task while driving, changes in speed were not significant after the correction for multiple comparison. No changes in standard deviation of lateral position (SDLP; 'weaving'), maximum speed, standard deviation of speed or reaction time were found at any time point or under either standard or dual task conditions. Mean THC levels were significantly increased, relative to control, after consuming the edible but remained relatively low at approximately 2.8 ng/mL 2 h after consumption. Driving impairment was not correlated with blood THC. Subjective experience was altered for 7 h and participants were less willing/able to drive for up to 6 h, suggesting that the edible was intoxicating. INTERPRETATION This is the first study of the impact of cannabis edibles on simulated driving. Edibles were intoxicating as revealed by the results of subjective assessments (VAS), and there was some impact on driving. Detection of driving impairment after the use of cannabis edibles may be difficult.
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Affiliation(s)
- S Zhao
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - B Brands
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
- Health Canada, Ottawa, ON, Canada
| | - P Kaduri
- Addictions Division, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
- Department of Psychiatry and Mental Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - C M Wickens
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
- Campbell Family Mental Health Research Institute, Toronto, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - O S M Hasan
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - S Chen
- Biostatistics Core, Centre for Addiction and Mental Health, Toronto, Canada
| | - B Le Foll
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, Toronto, Canada
- Department of Family and Community Medicine, University of Toronto, Toronto, Canada
| | - P Di Ciano
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.
- Campbell Family Mental Health Research Institute, Toronto, Canada.
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.
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Di Ciano P, Rajji TK, Hong L, Zhao S, Byrne P, Elzohairy Y, Brubacher JR, McGrath M, Brands B, Chen S, Wang W, Hasan OSM, Wickens CM, Kaduri P, Le Foll B. Cannabis and Driving in Older Adults. JAMA Netw Open 2024; 7:e2352233. [PMID: 38236599 PMCID: PMC10797455 DOI: 10.1001/jamanetworkopen.2023.52233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/29/2023] [Indexed: 01/19/2024] Open
Abstract
Importance Epidemiological studies have found that cannabis increases the risk of a motor vehicle collision. Cannabis use is increasing in older adults, but laboratory studies of the association between cannabis and driving in people aged older than 65 years are lacking. Objective To investigate the association between cannabis, simulated driving, and concurrent blood tetrahydrocannabinol (THC) levels in older adults. Design, Setting, and Participants Using an ecologically valid counterbalanced design, in this cohort study, regular cannabis users operated a driving simulator before, 30 minutes after, and 180 minutes after smoking their preferred legal cannabis or after resting. This study was conducted in Toronto, Canada, between March and November 2022 with no follow-up period. Data were analyzed from December 2022 to February 2023. Exposures Most participants chose THC-dominant cannabis with a mean (SD) content of 18.74% (6.12%) THC and 1.46% (3.37%) cannabidiol (CBD). Main outcomes and measures The primary end point was SD of lateral position (SDLP, or weaving). Secondary outcomes were mean speed (MS), maximum speed, SD of speed, and reaction time. Driving was assessed under both single-task and dual-task (distracted) conditions. Blood THC and metabolites of THC and CBD were also measured at the time of the drives. Results A total of 31 participants (21 male [68%]; 29 White [94%], 1 Latin American [3%], and 1 mixed race [3%]; mean [SD] age, 68.7 [3.5] years), completed all study procedures. SDLP was increased and MS was decreased at 30 but not 180 minutes after smoking cannabis compared with the control condition in both the single-task (SDLP effect size [ES], 0.30; b = 1.65; 95% CI, 0.37 to 2.93; MS ES, -0.58; b = -2.46; 95% CI, -3.56 to -1.36) and dual-task (SDLP ES, 0.27; b = 1.75; 95% CI, 0.21 to 3.28; MS ES, -0.47; b = -3.15; 95% CI, -5.05 to -1.24) conditions. Blood THC levels were significantly increased at 30 minutes but not 180 minutes. Blood THC was not correlated with SDLP or MS at 30 minutes, and SDLP was not correlated with MS. Subjective ratings remained elevated for 5 hours and participants reported that they were less willing to drive at 3 hours after smoking. Conclusions and relevance In this cohort study, the findings suggested that older drivers should exercise caution after smoking cannabis.
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Affiliation(s)
- Patricia Di Ciano
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Tarek K. Rajji
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Toronto Dementia Research Alliance, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lauren Hong
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sampson Zhao
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Patrick Byrne
- Ontario Ministry of Transportation, Toronto, Ontario, Canada
| | | | - Jeffrey R. Brubacher
- Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael McGrath
- Ontario Ministry of Transportation, Toronto, Ontario, Canada
| | - Bruna Brands
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
- Health Canada, Ottawa, Ontario, Canada
| | - Sheng Chen
- Biostatistics Core, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Wei Wang
- Biostatistics Core, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Omer S. M. Hasan
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Christine M. Wickens
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
| | - Pamela Kaduri
- Addictions Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Department of Psychiatry and Mental Health, Muhimbill University of Health and Allied Sciences, Tanzania
| | - Bernard Le Foll
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Acute Care Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada
- Waypoint Research Institute, Waypoint Centre for Mental Health Care, Penetanguishene, Ontario, Canada
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Hartley S, Simon N, Cardozo B, Larabi IA, Alvarez JC. Can inhaled cannabis users accurately evaluate impaired driving ability? A randomized controlled trial. Front Public Health 2023; 11:1234765. [PMID: 38074719 PMCID: PMC10703156 DOI: 10.3389/fpubh.2023.1234765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/26/2023] [Indexed: 12/18/2023] Open
Abstract
Aims To study the effect of inhaled cannabis on self-assessed predicted driving ability and its relation to reaction times and driving ability on a driving simulator. Participants and methods 30 healthy male volunteers aged 18-34: 15 chronic (1-2 joints /day) and 15 occasional (1-2 joints/week) consumers. Self-assessed driving confidence (visual analog scale), vigilance (Karolinska), reaction time (mean reciprocal reaction time mRRT, psychomotor vigilance test), driving ability (standard deviation of lane position SDLP on a York driving simulator) and blood concentrations of delta-9-tétrahydrocannabinol (THC) were measured before and repeatedly after controlled inhalation of placebo, 10 mg or 30 mg of THC mixed with tobacco in a cigarette. Results Cannabis consumption (at 10 and 30 mg) led to a marked decrease in driving confidence over the first 2 h which remained below baseline at 8 h. Driving confidence was related to THC dose and to THC concentrations in the effective compartment with a low concentration of 0.11 ng/ml for the EC50 and a rapid onset of action (T1/2 37 min). Driving ability and reaction times were reduced by cannabis consumption. Driving confidence was shown to be related to driving ability and reaction times in both chronic and occasional consumers. Conclusions Cannabis consumption leads to a rapid reduction in driving confidence which is related to reduced ability on a driving simulator. Clinical trial registration ClinicalTrials.gov, identifier: NCT02061020.
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Affiliation(s)
- Sarah Hartley
- Sleep Unit, Physiology Department, AP-HP GHU Paris-Saclay, Raymond Poincaré Hospital, Garches, France
| | - Nicolas Simon
- Department of Clinical Pharmacology, Aix Marseille Univ, APHM, INSERM, IRD, SESSTIM, Hop Sainte Marguerite, CAP-TV, Marseille, France
| | - Bibiana Cardozo
- Department of Clinical Pharmacology, Aix Marseille Univ, APHM, INSERM, IRD, SESSTIM, Hop Sainte Marguerite, CAP-TV, Marseille, France
| | - Islam Amine Larabi
- Plateform MasSpecLab, Department of Pharmacology and Toxicology, Raymond Poincaré Hospital, GHU AP-HP.Paris-Saclay, Paris-Saclay University, UVSQ, Inserm U-1018, CESP, Team MOODS, Garches, France
| | - Jean Claude Alvarez
- Plateform MasSpecLab, Department of Pharmacology and Toxicology, Raymond Poincaré Hospital, GHU AP-HP.Paris-Saclay, Paris-Saclay University, UVSQ, Inserm U-1018, CESP, Team MOODS, Garches, France
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