Cannabis-Impaired driving: ethical considerations for the primary care practitioner

Figures & data

Figure 1. Considerations for potentially vulnerable populations.

A summary highlighting the key points of consideration for cannabis-impaired driving management in potentially vulnerable populations.

Table

Databases	Keywords
Scopus	( TITLE-ABS-KEY ( cannabis-impaired  AND driving )  AND  TITLE-ABS-KEY ( confidentiality  OR  physician  OR  responsibilities  OR  duty  OR  to  OR  report  OR  harms  OR  risks ) )
Pubmed	(cannabis-impaired AND driving) AND (confidentiality OR physician OR responsibilities OR duty OR to OR report OR harms OR risks)
Pubmed with MeSH terms	("cannabis"[MeSH Terms] OR "cannabis"[All Fields] OR "cannabi"[All Fields] OR "cannabis s"[All Fields]) AND ("impair"[All Fields] OR "impaired"[All Fields] OR "impairement"[All Fields] OR "impairements"[All Fields] OR "impairing"[All Fields] OR "impairment"[All Fields] OR "impairments"[All Fields] OR "impairs"[All Fields]) AND ("automobile driving"[MeSH Terms] OR ("automobile"[All Fields] AND "driving"[All Fields]) OR "automobile driving"[All Fields] OR "driving"[All Fields] OR "drive"[MeSH Terms] OR "drive"[All Fields] OR "drives"[All Fields] OR "drivings"[All Fields]) AND ("confidential"[All Fields] OR "confidentiality"[MeSH Terms] OR "confidentiality"[All Fields] OR "confidentially"[All Fields] OR ("physician s"[All Fields] OR "physicians"[MeSH Terms] OR "physicians"[All Fields] OR "physician"[All Fields] OR "physicians s"[All Fields]) OR ("responsabilities"[All Fields] OR "responsability"[All Fields] OR "responsibilities"[All Fields] OR "responsibility"[All Fields] OR "responsible"[All Fields] OR "responsibles"[All Fields]) OR "duty"[All Fields] OR ("toxicity"[MeSH Subheading] OR "toxicity"[All Fields] OR "to"[All Fields]) OR ("reportable"[All Fields] OR "reporting"[All Fields] OR "reportings"[All Fields] OR "research report"[MeSH Terms] OR ("research"[All Fields] AND "report"[All Fields]) OR "research report"[All Fields] OR "report"[All Fields] OR "reported"[All Fields] OR "reports"[All Fields]) OR ("harmed"[All Fields] OR "harmful"[All Fields] OR "harmfulness"[All Fields] OR "harming"[All Fields] OR "harms"[All Fields]) OR ("risk"[MeSH Terms] OR "risk"[All Fields])) Translations cannabis: "cannabis"[MeSH Terms] OR "cannabis"[All Fields] OR "cannabi"[All Fields] OR "cannabis’s"[All Fields] impaired: "impair"[All Fields] OR "impaired"[All Fields] OR "impairement"[All Fields] OR "impairements"[All Fields] OR "impairing"[All Fields] OR "impairment"[All Fields] OR "impairments"[All Fields] OR "impairs"[All Fields] drive: "automobile driving"[MeSH Terms] OR ("automobile"[All Fields] AND "driving"[All Fields]) OR "automobile driving"[All Fields] OR "driving"[All Fields] OR "drive"[MeSH Terms] OR "drive"[All Fields] OR "drives"[All Fields] OR "drivings"[All Fields] confidentiality: "confidential"[All Fields] OR "confidentiality"[MeSH Terms] OR "confidentiality"[All Fields] OR "confidentially"[All Fields] physician: "physician’s"[All Fields] OR "physicians"[MeSH Terms] OR "physicians"[All Fields] OR "physician"[All Fields] OR "physicians’s"[All Fields] responsibilities: "responsabilities"[All Fields] OR "responsability"[All Fields] OR "responsibilities"[All Fields] OR "responsibility"[All Fields] OR "responsible"[All Fields] OR "responsibles"[All Fields] to: "toxicity"[Subheading] OR "toxicity"[All Fields] OR "to"[All Fields] report: "reportable"[All Fields] OR "reporting"[All Fields] OR "reportings"[All Fields] OR "research report"[MeSH Terms] OR ("research"[All Fields] AND "report"[All Fields]) OR "research report"[All Fields] OR "report"[All Fields] OR "reported"[All Fields] OR "reports"[All Fields] harms: "harmed"[All Fields] OR "harmful"[All Fields] OR "harmfulness"[All Fields] OR "harming"[All Fields] OR "harms"[All Fields] risk: "risk"[MeSH Terms] OR "risk"[All Fields]
Google Scholar	(cannabis-impaired AND driving) AND (confidentiality OR physician OR responsibilities OR duty OR to OR report OR harms OR risks)
	((cannabis OR alcohol) impaired AND driving) AND (confidentiality OR physician OR responsibilities OR duty OR to OR report OR harms OR risks)
Embase/Ovid	(cannabis-impaired and driving and (confidentiality or physician or responsibilities or duty or to or report or harms or risks)).mp. [mp = title, abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword heading word, floating subheading word, candidate term word]
Embase/Ovid with EMTREE terms	(exp/cannabis and exp/drive) and (exp/ethics or exp/risk)

Table

Year	Author	Title & Key Findings
2007	Bédard, M., Dubois, S. & Weaver, B.	The Impact of Cannabis on Driving Of the 32,543 drivers tested, 1,647 (5%) tested positive for cannabis. Drivers who tested positive were generally younger, male, and had a poorer driving record in the past three years. A greater proportion of drivers who tested positive for cannabis had a DRF related to speeding or erratic/reckless driving. The crude OR between DRFs and cannabis was 1.39 (99% CI = 1.21-1.59). After adjusting this association for age, sex, and driving record the OR for THC was 1.29 (99% CI = 1.11-1.50). Younger age and poorer driving records, but not sex, were also associated with a higher risk of a reported DRF
2018	Lee, J., Abdel-Aty, A. & Park, J.	Investigation of associations between marijuana law changes and marijuana-involved fatal traffic crashes: A state-level analysis Full legalization and decriminalization of marijuana have significant effects on marijuana-related crashes in all states.
2013	Li, G., Brady, J. E. & Chen, Q.	Drug use and fatal motor vehicle crashes: A case-control study Overall, 31.9% of the 737 cases and 13.6% of the 7719 controls tested positive for at least one non-alcohol drug, yielding a crude odds ratio of 2.98 (95% CI: 2.51, 3.53). As expected, male drivers and drivers aged 21 to 34 years or 65 years and older were at significantly increased risk of fatal crash involvement. The heightened risk of fatal crash involvement associated with drug use existed in each age group and in both sexes. Although drivers aged 35–44 years and female drivers appeared to be at particularly excess risk, the estimated odds ratios of fatal crash involvement did not vary significantly with age and sex. Polydrug use, defined as use of two or more non-alcohol drugs, was associated with a 3.4-fold increased risk of fatal crash involvement. The estimated odds ratios of fatal crash involvement associated marijuana was 1.83 [95% confidence interval (CI): 1.39, 2.39].
2016	Rogeberg, O. & Elvik, R.	The effects of cannabis intoxication on motor vehicle collision revisited and revised: Cannabis and motor vehicle collision risk The revised estimate from the studies used in Asbridge et al. was in line with the results from the expanded meta-analysis in study 2, lying between the pooled odds from the mixed-effects model of 1.36 (CI = 1.15–1.61) and the pooled odds from the PEESE meta-regression of 1.22 (meta-regression model, CI = 1.1–1.36). Acute cannabis intoxication is associated with a statistically significant increase in motor vehicle crash risk. The increase is of low to medium magnitude.
2020	Brubacher, J. R., Chan, H. & Staples, J. A.	Cannabis-impaired driving and Canadian youth Among Canadian National Cannabis Survey respondents aged 15 to 24 years, about one in four reported using cannabis in the previous 3 months, 14% reported driving within 2 h of using cannabis, and 12% reported being a passenger in a vehicle driven by someone who had used cannabis in the previous two hours. Among Canadian youth who use cannabis frequently, 80% of males and 75% of females reported that in the previous 30 days they had been in a car driven by someone (including themselves) who had recently used marijuana or other drugs and 64% of males and 33% of females reported being ‘intoxicated’ with marijuana while operating a vehicle. Cannabis impairs the psychomotor skills required for safe driving. Cannabis contains over 60 cannabinoids, but most impairing effects are caused by the main psychoactive compound, Δ-9-tetrahydrocannabinol (THC) (18). After taking cannabis, most people experience the desired effects of euphoria and relaxation, although some develop anxiety, panic, or even paranoia. After taking cannabis, drivers in traffic ‘weave’ more, sometimes to the point of being unable to stay within the traffic lanes (28). They also have difficulty maintaining a constant speed or a uniform gap between themselves and a lead vehicle (28). In simulator studies, drivers tend to slow down after using cannabis, have delayed reactions when responding to a sudden hazard, and are more likely to crash (29–32). This evidence suggests that people who drive after using cannabis might have a large increase in collision risk. Epidemiological studies show a modest increase in crash risk after cannabis use. Several recent meta-analyses all concluded that cannabis use increases crash risk, with odds ratios (ORs) ranging from 1.36 to 2.66 (34,35). Driving simulator studies and epidemiologic analyses suggest that cannabis use increases motor vehicle crash risk. Young, inexperienced drivers may be at a particularly high risk of crashing after using cannabis.
2017	Fischer, B. et al.	Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations Cannabis use acutely impairs key executive functions critical for driving, including cognition, attention, memory, decision-making, and psychomotor functioning. This occurs in a dose-dependent way, although the magnitude and persistence of impairments may vary with use patterns, THC concentration, tolerance, metabolism, and other factors. Some of these impairments have been found to persist after acute intoxication, particularly in chronic users. Following cannabis intake, peak THC plasma concentrations (around 100 ng/mL) are usually reached within approximately 5 to 30 min and generally taper off approximately 2 to 4 h later. However, intoxication and cognitive impairments may persist beyond THC plasma concentration peaks, yet typically clear within approximately 3 to 6 h. Higher THC or other cannabinoid concentration or ingested cannabis products (with an extended absorption period) can have more pronounced and persistent effects. Although these effects are based on the typical pharmacokinetics of THC, they may vary with inhalation intensity, lung capacity, and other factors.

Data availability statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study.