Driving Under The Influence Of Cannabis Research Articles

Reliability of roadside oral fluid testing devices for ∆9 -tetrahydrocannabinol (∆9 -THC) detection.

Driving under the influence of cannabis (DUIC) is increasing worldwide, and cannabis is the most prevalent drug after alcohol in impaired driving cases, emphasizing the need for a reliable traffic enforcement strategy. ∆9 -tetrahydrocannabinol (THC) detection in oral fluid has great potential for identifying recent cannabis use; however, additional data are needed on the sensitivities, specificities, and efficiencies of different oral fluid devices for detecting cannabinoids at the roadside by police during routine traffic safety enforcement efforts. At the roadside, 8945 oral fluid THC screening tests were performed with four devices: AquilaScan®, Dräger DrugTest®, WipeAlyser Reader®, and Druglizer®. A total of 530 samples screened positive for THC (5.9%) and were analyzed by liquid chromatography-tandem mass spectrometry at multiple cutoff concentrations (2ng/mL, 10ng/mL, and manufacturers' recommended device cutoffs) to investigate device performance. Results varied substantially, with sensitivities of 0%-96.8%, specificities of 89.8%-98.5%, and efficiencies of 84.3%-97.8%. The Dräger DrugTest® outperformed the other devices with a 96.8% sensitivity, 97.1% specificity, and 97.0% efficiency at a 5-ng/mL LC-MS/MS confirmation cutoff. The WipeAlyser Reader® had good performance with a 91.4% sensitivity, 97.2% specificity, and 96.4% efficiency. AquilaScan® and Druglizer® had unacceptable performance for cannabinoid detection, highlighted by sensitivity <13%. The choice of roadside oral fluid testing device must offer good analytical performance for cannabinoids because of its high prevalence of use and impact on road safety.

Drug driving: a secondary analysis of factors associated with driving under the influence of cannabis in Jamaica

ObjectivesTo determine cannabis use patterns, the predictive sociodemographic correlates of driving under the influence of cannabis (DUIC) and the association between risk perception and cannabis dependence among vehicle drivers in...

Driving-related behaviors, attitudes, and perceptions among Australian medical cannabis users: results from the CAMS 20 survey

Road safety is an important concern amidst expanding worldwide access to legal cannabis. The present study reports on the driving-related subsection of the Cannabis as Medicine Survey 2020 (CAMS-20) which surveyed driving-related behaviors, attitudes, and perceptions among Australian medical cannabis (MC) users. Of the 1063 respondents who reported driving a motor vehicle in the past 12 months, 28% (297/1063) reported driving under the influence of cannabis (DUIC). Overall, 49–56% of respondents said they typically drive within 6 h of MC use, depending on the route of administration (oral or inhaled). Non-medical cannabis (NMC) was perceived to be more impairing for driving than MC. Binary logistic regression revealed associations between likelihood of DUIC and (1) inhaled routes of cannabis administration, (2) THC-dominant products, (3) illicit rather than prescribed use, (4) believing NMC does not impair driving, and (5) not being deterred by roadside drug testing. Overall, these findings suggest there is a relatively low perception of driving-related risk among MC users. Targeted education programs may be needed to highlight the potential risks associated with DUIC, and further research is needed to determine whether driving performance is differentially affected by MC and NMC.

Media Framing of Causes, Risks, and Policy Solutions for Cannabis-Impaired Driving: Does Medical vs. Non-Medical Cannabis Context Matter?

ABSTRACT Driving under the influence of cannabis (DUIC) is a major cause of preventable death and a growing public health concern. News media coverage of DUIC may influence public perceptions of causal factors for DUIC, risks of DUIC, and potential policy solutions. This study examines Israeli news media coverage of DUIC, and contrasts media coverage according to whether news items refer to cannabis use for medical vs. non-medical purposes. We conducted a quantitative content analysis of news articles related to driving accidents and cannabis use (N = 299) from eleven of the highest circulation newspapers in Israel between 2008 and 2020. We apply attribution theory to analyze media coverage of accidents that were linked to medical cannabis, use compared with non-medical use. News items describing DUIC in the context of non-medical (vs. medical) cannabis use were more likely to: (a) emphasize individual causes (vs. social and political); (b) describe drivers in negative terms (vs. neutral or positive); (c) refer to an increased accident risk due to cannabis use (vs. inconclusive or low risk); and (d) call for increased enforcement rather than education. Results show that Israeli news media coverage of cannabis-impaired driving varied significantly depending on whether it referred to cannabis use for medical purposes, or non-medical purposes. News media coverage may influence public perceptions of the risks of DUIC, the factors that are associated with this issue, and potential policy solutions that may reduce the prevalence of DUIC in Israel.

The Quality, Readability, and Accuracy of the Information on Google About Cannabis and Driving: Quantitative Content Analysis

Background The public perception of driving under the influence of cannabis (DUIC) is not consistent with current evidence. The internet is an influential source of information available for people to find information about cannabis. Objective The purpose of this study was to assess the quality, readability, and accuracy of the information about DUIC found on the internet using the Google Canada search engine. Methods A quantitative content analysis of the top Google search web pages was conducted to analyze the information available to the public about DUIC. Google searches were performed using keywords, and the first 20 pages were selected. Web pages or web-based resources were eligible if they had text on cannabis and driving in English. We assessed (1) the quality of information using the Quality Evaluation Scoring Tool (QUEST) and the presence of the Health on the Net (HON) code; (2) the readability of information using the Gunning Fox Index (GFI), Flesch Reading Ease Scale (FRES), Flesch-Kincaid Grade Level (FKGL), and Simple Measure of Gobbledygook (SMOG) scores; and (3) the accuracy of information pertaining to the effects of cannabis consumption, prevalence of DUIC, DUIC effects on driving ability, risk of collision, and detection by law enforcement using an adapted version of the 5Cs website evaluation tool. Results A total of 82 web pages were included in the data analysis. The average QUEST score was 17.4 (SD 5.6) out of 28. The average readability scores were 9.7 (SD 2.3) for FKGL, 11.4 (SD 2.9) for GFI, 12.2 (SD 1.9) for SMOG index, and 49.9 (SD 12.3) for FRES. The readability scores demonstrated that 8 (9.8%) to 16 (19.5%) web pages were considered readable by the public. The accuracy results showed that of the web pages that presented information on each key topic, 96% (22/23) of them were accurate about the effects of cannabis consumption; 97% (30/31) were accurate about the prevalence of DUIC; 92% (49/53) were accurate about the DUIC effects on driving ability; 80% (41/51) were accurate about the risk of collision; and 71% (35/49) were accurate about detection by law enforcement. Conclusions Health organizations should consider health literacy of the public when creating content to help prevent misinterpretation and perpetuate prevailing misperceptions surrounding DUIC. Delivering high quality, readable, and accurate information in a way that is comprehensible to the public is needed to support informed decision-making.

Risk perceptions of driving under the influence of cannabis: Comparing medical and non-medical cannabis users

BackgroundReduced perception of potential harm resulting from cannabis use is associated with greater risk of driving under the influence of cannabis (DUIC). Understanding risk perceptions of DUIC among subgroups of users will positively inform targeting and content of anti-DUIC driver education and public awareness campaigns. The current study compared DUIC-related risk perceptions among individuals who use cannabis exclusively for non-medical purposes versus those who use cannabis for exclusively medical or for both medical and non-medical purposes (i.e., dual-purpose users). MethodData were drawn from a regionally stratified cross-sectional general population telephone survey of adults (18 + years) in Ontario, Canada conducted in 2017. Respondents who reported past-year use of cannabis and answered questions regarding DUIC risk perceptions were selected (weighted N = 343). Modified Poisson regression models with robust standard error estimation were conducted for three attitudes: disagree that DUIC increases motor vehicle collision risk, agree that DUIC is safer than driving under the influence of alcohol (DUIA), agree that chances of being caught by police for DUIA higher than DUIC. In addition to type of cannabis user (non-medical only versus medical or dual-purpose), covariates included demographic characteristics and past-year alcohol and cannabis use frequency. ResultsAdjusting for other covariates, regression analyses indicated that medical or dual-purpose cannabis users were 45 % more likely than non-medical users to agree that DUIC is safer than DUIA (Adjusted Prevalence Ratio = 1.45, 95 %CI = 1.10, 1.91, p = 0.007). No other differences in risk perception between medical or dual-purpose and non-medical cannabis users were found. DiscussionAlthough no difference between medical or dual-purpose and non-medical cannabis users was found in perceptions of collision risk associated with DUIC or risk of police enforcement, the perception that DUIC is safer than DUIA was stronger among medical or dual-purpose than non-medical users. Recognizing that the shift in public perception of DUIA as a high-risk behaviour contributed to reductions in incidence of DUIA, results of the current study support education and awareness campaigns that target medical or dual-purpose users and emphasize that, like DUIA, DUIC is also a high-risk behaviour.

Perceived Safety, Not Perceived Legality, Mediates the Relationship Between Cannabis Legalization and Drugged Driving.

Cannabis legalization has rapidly spread throughout the United States and is associated with multiple public health outcomes, including driving under the influence of cannabis (DUIC). To improve understanding of the relationship between legalization and DUIC, we tested two potential mediators of this relationship: perceived safety and perceived legality of driving high. We analyzed data from 1,236 current (past 30-day) cannabis users who were recruited from states with recreational, medical only, or no legal cannabis between 2016 and 2017 using address-based and social media samples. Using a generalized linear model and adjusting for cannabis legalization, demographics, living in a state with a cannabis-specific drugged driving law, frequency of cannabis use, and weights, we found that perceived safety (risk ratio [RR] = 2.60, 95% CI [1.88, 3.58]), but not perceived legality (RR = 0.96, 95% CI [0.67, 1.37]), was significantly associated with DUIC. Perceived safety mediated the relationship between legalization and DUIC (Coeff: -0.12, 95% CI [-0.23, -0.01]). Models stratified by frequency of cannabis use yielded results consistent with those of pooled models except that, for frequent users, cannabis-specific driving laws were associated with a significantly lower risk of DUIC (RR = 0.64, 95% CI [0.44, 0.92]). Agencies developing cannabis-focused drugged driving educational campaigns should consider the potential role of perceived safety of driving high in DUIC campaigns.

Driving under the influence of cannabis among recreational and medical cannabis users: A population study

BackgroundComparisons of individuals using cannabis for medical versus recreational purposes have identified differences in health status, alcohol and drug use, and perceived risk of drug use. All of these factors are associated with aggressive and impaired driving and collision risk. Yet, few studies comparing medical and recreational cannabis users have considered differences in driver behaviour and road safety. AimThis study examined the association between type of cannabis use (medical versus recreational-only) and engaging in driving under the influence of cannabis (DUIC), controlling for suspected confounding variables. MethodData were derived from a regionally stratified cross-sectional general population telephone survey of adults (18+ years) in Ontario, Canada conducted from 2014 to 2019. Respondents reporting past-year operation of a vehicle and past-year use of cannabis were selected (N = 1392). A binary logistic regression was conducted to assess the association between type of cannabis user (medical versus recreational-only) and self-reported DUIC, controlling for cannabis use frequency, hazardous drinking, perceived general and mental health, demographic characteristics, driving exposure, and interview year. ResultsIn total, 9.7 percent of recreational-only users reported DUIC compared to 27.0 percent of medical users. Adjusting for covariates, medical cannabis users had almost two times greater odds of DUIC than recreational-only users (AdjOR = 1.78, p = .037, 95%CI = 1.03, 3.05). DiscussionA higher proportion of medical cannabis users, relative to recreational-only users, engaged in DUIC. This finding has important implications for improving the effectiveness of public health interventions designed to reduce DUIC. Further research examining the harms of medical versus recreational cannabis use for road safety is needed.

A scoping review of predictors of driving under the influence of cannabis (DUIC) in young drivers

BackgroundRecreational and medical legalization of cannabis or marijuana use in countries and states continues to increase. Young adults aged 16–24 years have the highest prevalence rates of cannabis use. Young driver cannabis use is an incompletely understood traffic safety issue. ObjectivesThe purposes of this scoping review were to characterize the predictors of driving under the influence of cannabis (DUIC) among healthy young drivers and to identify research gaps. Inclusion criteriaA self-reported measure of DUIC and a correlation (r, odds ratio, risk ratio) to demographic or behavioral variables such as age, gender and frequency of use was required for inclusion Sources of evidenceAPA PsycInfo, SPORTDiscus, Academic Search Complete, Google Scholar, MEDLINE Complete, Scopus, Embase, ERIC, TRID and POPLINE databases were searched using an a priori protocol. MethodsThe PRISMA-ScR methods and checklist were used to conduct the scoping review. After the removal of duplicates, abstract screening (N = 999), and full-text review (N = 173), 19 primary studies met inclusion criteria. Predictors were coded and mapped into four primary thematic categories: social, individual, driving and substance use. ResultsOf the included studies, a total of 52,197 respondents were surveyed in-person or online and 51.8 percent were males. The predominant predictors of DUIC included being a male, high school senior, with lower grades, having a younger ‘age of first cannabis use’, a higher frequency of consumption, a reduced perception of danger, repeatedly binge drinking, a history of driving under the influence of alcohol and living with fewer parents. Research gapsIdentified research gaps include methods used to study young drivers, cannabis edibles, chronic user tolerance, driver adaptation, passengers of drivers who consumed cannabis, combined use with other legal and illicit drugs, and combined smartphone and cannabis use. ConclusionThe results of this scoping review can be used to develop and target general and specific predictors of DUIC in novice, teen and young drivers. Additional research designs will be required to gain a more complete evidence-based understanding of the effects of cannabis on young drivers.

Mobile-based brief interventions targeting cannabis-impaired driving among youth: A Delphi study

IntroductionBrief interventions delivered using mobile technologies have become popular to reduce youth alcohol use, however, few have been applied to cannabis use and driving under the influence of cannabis (DUIC). This Delphi study sought to create and compare consensus among a panel of experts (potential intervention developers) and a panel of youth (intervention audience) on the characteristics to prioritize in a youth DUIC mobile-based brief intervention. MethodsA two-round two-panel Delphi study was conducted among 26 professionals with expertise in youth substance use and impaired driving and 20 youth who use cannabis. Participants ranked the importance of 45 evidence-informed intervention characteristics using a 7-point Likert scale. Characteristics that received an interquartile deviation score ≤ 1 (indicating consensus) and a median score of ≥6 (indicating importance) in both panels were considered shared priorities. Differences in panel rankings were quantified using Mann-Whitney U tests. ResultsConsensus was achieved for 41 characteristics in the professional panel and 34 in the youth panel, with ratings generally higher among professionals. Overall, 16 shared priorities emerged. These include critical theoretical characteristics (e.g., self-efficacy, motivation, overcoming barriers), practical characteristics (e.g., mobile availability, estimates of intervention length, ability to input behaviours) and core contents (e.g., real-life stories, education on the risks/dangers, appropriate messaging). Youth's perceptions on the dangers of DUIC received the most support for an intervention outcome. ConclusionsFindings can inform the development of mobile-based brief interventions for youth, an essential step in reducing DUIC among youth and addressing this public health concern.

Cannabis legalization and driving under the influence of cannabis in a national U.S. Sample

The relationship between cannabis legalization and traffic safety remains unclear. Physiological measures of cannabis impairment remain imperfect. This analysis used self-report data to examine the relationship between cannabis legalization and driving under the influence of cannabis (DUIC)11DUIC: Driving under the influence of cannabis..Using a cross-sectional national sample (2016–2017) of 1,249 past–30-day cannabis users, we regressed self-reported DUIC (driving within three hours of “getting high”) on cannabis legalization (recreational and medical (recreational), medical only (medical), or no legal cannabis), adjusting for demographics, days of use (past 30 days), days of use*legal status, calibration weights, and geographic clustering.The risk of DUIC in recreational (risk ratio [RR] = 0.41, 95% confidence interval (CI):0.23–0.72) and medical (RR = 0.39, 95% CI:0.20–0.79) states was lower than in states without legal cannabis, with one exception. Among frequent cannabis users (≥20 days per month), there was a significantly lower risk of DUIC for those living in recreational states (RR = 0.70, 95% CI: 0.49–0.99), but not for those living in medical states (RR = 0.87, 95% CI: 0.60–1.24), compared to users living in states without legal cannabis.The risk of self-reported DUIC was lower in recreational and medical cannabis states compared to states without legal cannabis. The only exception was for frequent users in medical states, for whom there was no difference in risk compared to frequent users living in states without legal cannabis.

Exploring youths’ beliefs towards cannabis and driving: A mixed method study

BackgroundPreventing youth from driving under the influence of cannabis (DUIC) remains a road safety priority. This study aimed to understand beliefs of young Ontarian drivers (ages 18–24) towards cannabis use and DUIC. MethodsUsing a mixed methods design, we conducted an online survey (n = 426, 53% female) and two focus groups (n = 12, 67% female). The survey obtained data in the following sections: demographics, experiences and expectancies related to cannabis use and DUIC, knowledge and credibility of the law, attitudes towards DUIC, and social controls. Quantitative data was analyzed in SPSS using descriptive statistics and chi squares. Two focus groups were then conducted to contextualize quantitative findings. Audio recordings were transcribed and analyzed using inductive thematic analysis. Results83.6% (356) of survey’s participants had used cannabis, with 69% (296) in the past year. Among past-year users, 47.9% (142; 33.3% of the sample) reported DUIC. Those who indicated prior history of DUIC were mostly males, had completed less than a bachelor’s degree, and were students without employment. Qualitative themes included: Being high changes you; it is hard to tell if a driver is high; DUIC is convenient, socially acceptable, and safe; legalization makes cannabis more attractive to use; and there is a need for testing, education, and prevention efforts that are relevant to youth. ConclusionsA considerable number of young drivers in Ontario are currently DUIC, many of which underestimate the associated risks. Our findings provide insight into youth’s beliefs towards DUIC and considerations for preventative efforts.

Driving under the influence of cannabis risk perceptions and behaviour: A population-based study in Ontario, Canada

Driving under the influence of cannabis (DUIC) is detrimental to road safety. Risk perception is a strong determinant of DUIC behaviour, yet little is known about the factors influencing DUIC risk perception in the general population. The objective of this study was to identify factors associated with risk perceptions of motor vehicle collision and legal consequences due to DUIC and examine whether these perceptions were associated with DUIC behaviour. Data were derived from the 2017 CAMH Monitor, a cross-sectional telephone survey of adults aged 18+ years in Ontario, Canada (n = 1813). Multivariable logistic regression analyses were performed. Approximately 90% of adults overall agreed that DUIC increases motor vehicle collision risk compared to 55% of those reporting past-year DUIC. Being male, less educated, and using cannabis at least monthly were associated with disagreeing that DUIC increases motor vehicle collision risk. Being male, young, and using cannabis at least monthly were associated with agreeing that DUIC is safer than driving under the influence of alcohol (DUIA). Being male and using cannabis less than monthly were associated with agreeing that the chances of getting caught for DUIC are higher than DUIA. Safety but not legal risk perceptions were associated with DUIC behaviour among cannabis-using drivers. Cannabis legalization provides a timely opportunity for DUIC prevention strategies. This study suggests that policymakers should target male cannabis users and highlight the safety risks of DUIC. Further research is needed to assess the effectiveness of prevention measures and the impact of cannabis legalization on DUIC perceptions and behaviour.

Biomarkers of Recent Cannabis Use in Blood, Oral Fluid and Breath.

Proving driving under the influence of cannabis (DUIC) is difficult. Establishing a biomarker of recent use to supplement behavioral observations may be a useful alternative strategy. We determined whether cannabinoid concentrations in blood, oral fluid (OF) or breath could identify use within the past 3 h-likely the period of the greatest impairment. In a randomized trial, 191 frequent (≥4/week) and occasional (<4/week) cannabis users smoked one cannabis (placebo [0.02%], or 5.9% or 13.4% Δ9-tetrahydrocannabinol [THC]) cigarette ad libitum. Blood, OF and breath samples were collected prior to and up to 6 h after smoking. Samples were analyzed for 10 cannabinoids in OF, 8 in blood and THC in breath. Frequent users had more residual THC in blood and were more likely to be categorized as 'recently used' prior to smoking; this did not occur in OF. Per se limits ranging from undetectable to 5 ng/mL THC in blood offered limited usefulness as biomarkers of recent use. Cannabinol (CBN, cutoff = 1 ng/mL) in blood offered 100% specificity but only 31.4% sensitivity, resulting in 100% positive predictive value (PPV) and 94.0% negative predictive value (NPV) at 4.3% prevalence; however, CBN may vary by cannabis chemovar. A 10 ng/mL THC cutoff in OF exhibited the overall highest performance to detect its use within 3 h (99.7% specificity, 82.4% sensitivity, 92.5% PPV and 99.2% NPV) but was still detectable in 23.2% of participants ∼4.4 h post-smoking, limiting specificity at later time points. OF THC may be a helpful indicator of recent cannabis intake, but this does not equate to impairment. Behavioral assessment of impairment is still required to determine DUIC. This study only involved cannabis inhalation, and additional research evaluating alternative routes of ingestion (i.e., oral) is needed.

Young drivers' determinants of driving under the influence of cannabis: Findings from the Youth Cannabis and Driving Survey (YouCanDS)

Introduction: Driving under the influence of cannabis (DUIC) is proven to increase the risk of collisions and is most common among young drivers (ages 16 to 24). However, little is known about the specific determinants of DUIC behavior among youth, which limits the capacity to develop evidence-based prevention and intervention efforts. This study developed and evaluated a youth DUIC questionnaire, which was used to establish the DUIC determinants of young drivers. Method: The questionnaire was based on the theoretical framework of general deterrence and general prevention. Data obtained included: demographics, past cannabis use and DUIC experiences, DUIC intention, experiences riding as a passenger with someone DUIC, knowledge and credibility of the law, attitudes towards DUIC, and social controls. The resulting questionnaire was validated for a sample of 426 young drivers in the province of Ontario, Canada. An ordinal regression was conducted to examine the relationships between questionnaire items and DUIC intention. Results: The questionnaire displayed good construct validity and internal consistency across four out of five domains (KMO and Cronbach α values ≥ 0.70). Of the 426 respondents (52.6% female), 356 (83.6%) reported previous cannabis use, with 296 (69.5%) doing so in the past year, and 142 (33.3%) reporting DUIC. Furthermore, 179 (42%) study participants indicated at least a slight chance of DUIC in the next year. The regression analysis identified six variables predictive of DUIC intention: past DUIC incidence, perceived percent of those convicted that receive the penalty, moral awareness, perceived dangerousness, minor accident risk, and vicarious punishment avoidance. Conclusions: Preventive efforts should emphasize these determinants when designing targeted strategies and interventions. Practical Applications: These efforts should focus on educating the dangers and risk of a vehicle collision, that law enforcement has the capacity to apprehend and appropriately punish individuals DUIC, and that DUIC is wrong and socially unacceptable.

Modeling the system of beliefs that influence driving under the influence of cannabis (DUIC)

Cannabis use is increasing in the U.S. Driving under the influence of cannabis (DUIC) may be increasing as well potentially resulting in fatal and serious injury crashes. The purpose of this article is to explore the belief system associated with driving under the influence of cannabis (DUIC) using structural equation modeling (SEM). A sample (n = 2,084) of surveys collected from adults in the U.S. was analyzed using SEM to reveal the latent structure of the belief system associated with DUIC. The results of this analysis indicated that reported DUIC behavior (frequency and recency) was predicted by willingness that influenced intention. Willingness and intention were directly influenced by control beliefs, attitudes, norms, and attitudes (prototype image) toward people who never DUIC. Intention was also influenced by attitudes toward people who do DUIC. Intention had a stronger influence on DUIC than willingness alone. These components were influenced by underlying behavioral, normative, and control beliefs. Thus, strategies that can change these beliefs may also reduce DUIC.

Driving-Related Behaviours, Attitudes and Perceptions among Australian Medical Cannabis Users: Results from the CAMS 18-19 Survey

As the use of cannabis for medical purposes becomes increasingly prevalent, driving under the influence of cannabis (DUIC) is emerging as a major public health issue. Understanding current behaviours, attitudes and perceptions around DUIC in medical cannabis users is an important first step in addressing this issue. Here we present the results from the driving-related subsection of the Cannabis as Medicine 2018-2019 Survey (CAMS18) of current Australian medical cannabis users (n = 1388). Of the 806 respondents who reported driving a motor vehicle in the last month, 34.6% said they typically drive within 3 hours of cannabis use, thereby risking DUIC, while more than 50% waited at least 7 hours before driving. A majority of respondents thought that their medical cannabis use did not affect their driving ability, and most denied any specific effects of cannabis on speeding, risk taking, reaction time, attentiveness or lane departures. A substantial majority (70.9%) felt confident in accurately assessing their own driving ability after using medical cannabis. Binary logistic regression showed that frequency of use and confidence to assess driving ability were strongly related to DUIC behaviour (i.e. driving soon after cannabis use). These results suggest a relatively high prevalence of DUIC and low perception of risk among this sample of medical cannabis users. Further research is needed to better understand the acute and chronic effects of medical cannabis use on driving and the relation between perceived and actual driving ability.

Cannabis-related driving and passenger behaviours among high school students: a cross-sectional study using survey data.

Many youth report driving under the influence of cannabis (DUIC) and riding with a cannabis-impaired driver (RWCD), and many perceive that cannabis causes limited impairment. We examined associations of perceived risk of regular cannabis use with DUIC and RWCD, exploring differences by sex and rural setting. In a cross-sectional study, we examined DUIC and RWCD among high school students in grades 11 and 12 who participated in the 2016-2017 Canadian Student Tobacco, Alcohol and Drugs Survey. Private and public schools across 9 Canadian provinces were included. New Brunswick and the 3 territories were not included. Multinomial logistic regression models generated adjusted and unadjusted models for the associations. A total of 52 103 students in grades 7-12, from 117 school boards and 699 schools, participated in the survey. The survey response rate was 76.2% (n = 52 103/68 415). In total, 14 520 students in grades 11 and 12 participated in the survey. Greater perceived risk of regular cannabis use was associated with reduced risk of DUIC and RWCD in a dose-response manner. Students perceiving that regular cannabis use posed great risk had an adjusted relative risk (RR) of 0.06 (95% confidence interval [CI] 0.04-0.10) of DUIC in the past 30 days compared with students perceiving that regular use posed no risk. Students perceiving that regular cannabis use posed great risk had an adjusted RR of 0.09 (95% CI 0.07-0.12) of RWCD in the past 30 days compared with students perceiving no such risk. Associations were consistent for male and female students and for those living in urban and rural areas. Students perceiving minimal risk from cannabis use reported greater engagement in cannabis-related risky driving behaviours. Given the importance of youth perceptions in shaping driving and passenger behaviours, efforts must be made to disseminate appropriate information regarding cannabis-related driving risks to high school students.

Sex differences in driving under the influence of cannabis: The role of medical and recreational cannabis use

BackgroundExisting evidence suggest that cannabis may impair driving and is the most prevalent drug identified in drivers. Males exhibit an excess risk for driving under the influence of drugs or alcohol compared to females. We assessed sex differences in the association between the reason for cannabis use (medical, recreational, or both) and driving under the influence of cannabis (DUIC). MethodsA sample of 17,405 past 12-month cannabis users (18 + years old) were analyzed from the 2016–17 National Survey on Drug Use and Health. Multivariable logistic regression was used to assess the interaction of sex and reason for cannabis use on DUIC using predicted probabilities. ResultsAmong cannabis users in the sample, 88.1% used for recreational reasons, 7.8% used for medical reasons, and 4.1% used for medical and recreational reasons. The probability of DUIC was as low as 20% among female medical only users, and as high as 40% among male combined medical and recreational users. Females showed more similar probabilities of DUIC across reasons of use (range 20% to 25%s) than males (range 28% to 40%). The difference in the probability of DUIC between combined medical and recreational users and recreational only users was significantly greater among males than among females (Δ 0.1, p < 0.05). ConclusionsThe observed effects of sex and reasons for cannabis use on DUIC suggests a need for targeted educational interventions, particularly among males reporting combined medical and recreational marijuana use.

Medical marijuana laws and driving under the influence of marijuana and alcohol.

Medical marijuana law (MML) enactment in the United States has been associated with increased cannabis use but lower traffic fatality rates. We assessed the possible association of MML and individual-level driving under the influence of cannabis (DUIC) and also under the influence of alcohol (DUIA). Three cross-sectional U.S. adult surveys: The National Longitudinal Alcohol Epidemiologic Survey (NLAES; 1991-1992), the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002), and the NESARC-III (2012-2013). The total n was 118 497: 41 764, 41 184, and 35 549 from NLAES, NESARC, and NESARC-III, respectively. Across the three surveys, similar questions in the Alcohol Use Disorder and Associated Disabilities Interview Schedule assessed DUIC and DUIA. Ever-MML states enacted MML between 1991-1992 and 2012-2013 (overall period). Early-MML states enacted MML between 1991-1992 and 2001-2002 (early period). Late-MML states enacted MML between 2001-2002 and 2012-2013 (late period). MML effects on change in DUIC and DUIA prevalence were estimated using a difference-in-differences specification to compare changes in MML and other states. From 1991-1992 to 2012-2013, DUIC prevalence nearly doubled (from 1.02% to 1.92%), increasing more in states that enacted MML than other states (difference-in-differences [DiD]=0.59%; 95% CI=0.06%-1.12%). Most change in DUIC prevalence occurred between 2001-2002 and 2012-2013. DUIC prevalence increased more in states that enacted MML 2001-2002 to 2012-2013 than in never-MML states (DiD=0.77%; 95% CI=-0.05%-1.59%), and in two early-MML states, California (DiD=0.82; 95% CI=0.06-1.59) and Colorado (DiD=1.32; 95% CI=0.11-2.53). In contrast, DUIA prevalence appeared unrelated to MML enactment. Medical marijuana law enactment in US states appears to have been associated with increased prevalence of driving under the influence of cannabis, but not alcohol.