Combined effect of alcohol and cannabis on simulated driving

Andrew Fares; Christine M Wickens; Robert E Mann; Patricia Di Ciano; Madison Wright; Justin Matheson; Omer S M Hasan; Jurgen Rehm; Tony P George; Andriy V Samokhvalov; Paul A Shuper; Marilyn A Huestis; Gina Stoduto; Timothy Brown; Cristiana Stefan; Dafna Sara Rubin-Kahana; Bernard Le Foll; Bruna Brands

doi:10.1007/s00213-021-05773-3

Combined effect of alcohol and cannabis on simulated driving

Psychopharmacology (Berl). 2022 May;239(5):1263-1277. doi: 10.1007/s00213-021-05773-3. Epub 2021 Feb 5.

Authors

Andrew Fares^{1

2}, Christine M Wickens^{2

3

4

5}, Robert E Mann^{2

3}, Patricia Di Ciano^{1

2

4}, Madison Wright^{1

2}, Justin Matheson^{1

2}, Omer S M Hasan^{2

3}, Jurgen Rehm^{2

3

4

6

7

8

9

10}, Tony P George^{6

11}, Andriy V Samokhvalov^{2

6}, Paul A Shuper^{2

3

4}, Marilyn A Huestis¹², Gina Stoduto², Timothy Brown¹³, Cristiana Stefan^{14

15}, Dafna Sara Rubin-Kahana^{6

16}, Bernard Le Foll^{1

4

6

16

17}, Bruna Brands^{18

19

20}

Affiliations

¹ Department of Pharmacology and Toxicology, University of Toronto, 27 King's College Circle, Toronto, Ontario, M5S 3H7, Canada.
² Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, 33 Ursula Franklin Street, Toronto, Ontario, M5S 2S1, Canada.
³ Dalla Lana School of Public Health, University of Toronto, 155 College Street, Toronto, Ontario, M5T 3M7, Canada.
⁴ Campbell Family Mental Health Research Institute Centre for Addiction and Mental Health, Ursula Franklin Street, Toronto, Ontario, M5S 2S1, Canada.
⁵ Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 425 - 155 College Street, Toronto, Ontario, M5T 1P8, Canada.
⁶ Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.
⁷ World Health Organization/Pan American Health Organization Collaborating Centre, Centre for Addiction and Mental Health, 33 Ursula Franklin Street, Toronto, Ontario, M5S 2S1, Canada.
⁸ Institute of Clinical Psychology and Psychotherapy & Center of Clinical Epidemiology and Longitudinal Studies (CELOS), Technische Universität Dresden, Chemnitzer Str. 46, 01187, Dresden, Germany.
⁹ Faculty of Medicine, Institute of Medical Science, University of Toronto, Medical Sciences Building, 1 King's College Circle, Room 2374, Toronto, Ontario, M5S 1A8, Canada.
¹⁰ Department of International Health Projects, Institute for Leadership and Health Management, I.M. Sechenov First Moscow State Medical University, Trubetskaya str., 8, b. 2, Moscow, Russian Federation, 119992.
¹¹ Biobehavioural Addictions and Concurrent Disorders Research Laboratory, Addictions Division, CAMH, 33 Ursula Franklin Street, Suite 1910A, Toronto, Ontario, M5S 2S1, Canada.
¹² Institute of Emerging Health Professions, Thomas Jefferson University, 1020 Walnut Street, Philadelphia, PA, 19107, USA.
¹³ National Advanced Driving Simulator, University of Iowa, 2401 Oakdale Blvd, Iowa City, IA, 52242, USA.
¹⁴ Clinical Laboratory and Diagnostic Services, Centre for Addiction and Mental Health, 100 Stokes Street, Toronto, Ontario, M6J 1H4, Canada.
¹⁵ Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
¹⁶ Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, 33 Ursula Franklin Street, Toronto, Ontario, M5S 2S1, Canada.
¹⁷ Department of Family and Community Medicine, University of Toronto, 500 University Avenue, 5th Floor, Toronto, Ontario, M5G 1V7, Canada.
¹⁸ Department of Pharmacology and Toxicology, University of Toronto, 27 King's College Circle, Toronto, Ontario, M5S 3H7, Canada. bruna.brands@canada.ca.
¹⁹ Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, 33 Ursula Franklin Street, Toronto, Ontario, M5S 2S1, Canada. bruna.brands@canada.ca.
²⁰ Controlled Substances and Cannabis Branch, Health Canada, Ottawa, Ontario, Canada. bruna.brands@canada.ca.

PMID: 33544195
DOI: 10.1007/s00213-021-05773-3

Abstract

Rationale: With alcohol and cannabis remaining the most commonly detected drugs in seriously and fatally injured drivers, there is a need to understand their combined effects on driving.

Objectives: The present study examined the effects of combinations of smoked cannabis (12.5% THC) and alcohol (target BrAC 0.08%) on simulated driving performance, subjective drug effects, cardiovascular measures, and self-reported perception of driving ability.

Methods: In this within-subjects, double-blind, double-dummy, placebo-controlled, randomized clinical trial, cannabis users (1-7 days/week) aged 19-29 years attended four drug administration sessions in which simulated driving, subjective effects, cardiovascular measures, and whole blood THC and metabolite concentrations were assessed following placebo alcohol and placebo cannabis (<0.1% THC), alcohol and placebo cannabis, placebo alcohol and active cannabis, and alcohol and active cannabis.

Results: Standard deviation of lateral position in the combined condition was significantly different from the placebo condition (p < 0.001). Standard deviation of lateral position was also significantly different from alcohol and cannabis alone conditions in the single task overall drive (p = 0.029 and p = 0.032, respectively), from the alcohol alone condition in the dual task overall drive (p = 0.022) and the cannabis alone condition in the dual task straightaway drive (p = 0.002). Compared to the placebo condition, the combined and alcohol conditions significantly increased reaction time. Subjective effects in the combined condition were significantly greater than with either of the drugs alone at some time points, particularly later in the session. A driving ability questionnaire showed that participants seemed unaware of their level of impairment.

Conclusion: Combinations of alcohol and cannabis increased weaving and reaction time, and tended to produce greater subjective effects compared to placebo and the single drug conditions suggesting a potential additive effect. The fact that participants were unaware of this increased effect has important implications for driving safety.

Keywords: Alcohol; Cannabis; Driving; Reaction time; Subjective effects; THC; Weaving.

Publication types

Randomized Controlled Trial

MeSH terms

Analgesics / pharmacology
Automobile Driving*
Cannabinoid Receptor Agonists / pharmacology
Cannabis*
Double-Blind Method
Dronabinol
Ethanol / adverse effects
Hallucinogens* / pharmacology
Humans
Marijuana Smoking*
Psychomotor Performance

Substances

Analgesics
Cannabinoid Receptor Agonists
Hallucinogens
Ethanol
Dronabinol

Abstract

Publication types

MeSH terms

Substances

Grants and funding