Drugged driving: increased traffic risks involving licit and illicit substances

Road hazard: a systematic review of traffic injuries following recreational cannabis legalization

PURPOSE

Acute cannabis use is associated with impaired driving performance and increased risk of motor vehicle crashes. Following the Canadian Cannabis Act's implementation, it is essential to understand how recreational cannabis legalization impacts traffic injuries, with a particular emphasis on Canadian emergency departments. This study aims to assess the impact of recreational cannabis legalization on traffic-related emergency department visits and hospitalizations in the broader context of North America.

METHODS

A systematic review was conducted according to best practices and reported using PRISMA 2020 guidelines. The protocol was registered on July 5, 2022 (PROSPERO CRD42022342126). MEDLINE(R) ALL (OvidSP), Embase (OvidSP), CINAHL (EBSCOHost), and Scopus were searched without language or date restrictions up to October 12, 2023. Studies were included if they examined cannabis-related traffic-injury emergency department visits and hospitalizations before and after recreational cannabis legalization. The risk of bias was assessed. Meta-analysis was not possible due to heterogeneity.

RESULTS

Seven studies were eligible for the analysis. All studies were conducted between 2019 and 2023 in Canada and the United States. We found mixed results regarding the impact of recreational cannabis legalization on emergency department visits for traffic injuries. Four of the studies included reported increases in traffic injuries after legalization, while the remaining three studies found no significant change. There was a moderate overall risk of bias among the studies included.

CONCLUSIONS

This systematic review highlights the complexity of assessing the impact of recreational cannabis legalization on traffic injuries. Our findings show a varied impact on emergency department visits and hospitalizations across North America. This underlines the importance of Canadian emergency physicians staying informed about regional cannabis policies. Training on identifying and treating cannabis-related impairments should be incorporated into standard protocols to enhance response effectiveness and patient safety in light of evolving cannabis legislation.

Carbon fiber-sampling combined flame ionization mass spectrometry for direct analysis of drugs in oral fluid

Drug-impaired driving poses a significant risk of collisions and other hazardous accidents, emphasizing the urgent need for simple and rapid roadside detection methods. Oral fluid, as an easily collectible and non-invasive test material, has gained widespread use in detecting drug-impaired driving. In this study, we have devised a method for direct sampling using a carbon fiber bundle combined with flame ionization mass spectrometry. The essence of this method lies in the synergy between the adsorption properties of carbon fiber and the plasma characteristics of the flame. Leveraging the strong adsorption capabilities of the carbon fiber bundle allows for the use of a minimal sample size (<100 μL) during sampling, presenting a distinct advantage in the roadside inspection and sampling process. Throughout the flame ionization process, proteins and salts within the oral fluid matrix adhere well to the carbon fiber bundle, while small molecule targets can be efficiently desorbed and react with charged species in the flame, leading to ionization. The results demonstrate the successful development of carbon fiber-sampling combined flame ionization mass spectrometry, capable of qualitative and quantitative analysis of drugs in oral fluid without the need for sample pre-treatment. Its quantitative capabilities are sufficient for real sample detection, providing an effective analytical method for the roadside detection of drugs in oral fluids.

A descriptive analysis of drivers under the influence of opioids in Kentucky

Despite the ongoing opioid epidemic and evidence of the increasing prevalence of driving under the influence of opioids, particularly in rural communities, there remains a limited understanding of those who drive under the influence of opioids. The current study aims to fill this gap in the literature by examining drivers under the influence of opioids (DUIOs) using the clinical substance use assessment records of a statewide sample of drivers convicted of driving under the influence (N = 15,917); first identifying differences between DUIOs and drivers under the influence of other, non-opioid substances, followed by an examination of factors associated with driving under the influence of opioids in combination with other substances, and finally, comparing rural and urban DUIOs (N = 1,571). Bivariate analyses were used to compare groups, while a logistic regression model was used to identify correlates of other substance involvement. DUIOs differed from drivers under the influence of other, non-opioid substances, such as being more likely to be convicted in a rural community (65.7% vs 53.6%) and to be under the influence of multiple substances at the time of arrest (42.0% vs 7.1%). Among DUIOs, a rural conviction (p =.016) and meeting DSM criteria for an alcohol (p <.001) and drug use disorder (p <.001) were positively associated with driving under the influence of opioids in combination with other substances. Results also highlighted a number of differences between rural and urban DUIOs, including other substance involvement. Urban DUIOs were more likely to report alcohol involvement in their DUI arrest (16.7% vs 9.1%), and rural DUIOs were more likely to report other, non-opioid drug involvement (36.9% vs 29.1%). Results suggest a possible need for different prevention and treatment approaches depending on rural/urban environment, which is noteworthy given limited treatment availability and other barriers to substance use treatment in rural communities.

Impaired driving among rural female drug-involved offenders

OBJECTIVE

Very little is known about rural female impaired drivers despite disproportionate rates of impaired driving arrests and associated traffic fatalities in rural areas. The present study examined past-year impaired driving histories and impaired driving correlates in a sample of rural female drug-involved offenders.

METHODS

Female drug-involved offenders (N = 400) from 3 rural jails completed a confidential interview focused on substance use and related risk behaviors. After removing cases with missing data (n = 23), participants self-reporting past-year impaired driving (n = 254) were compared to those who did not (n = 123) on demographic characteristics, substance use, mental health, and criminal histories. Impaired drivers also reported the substances involved in their past-year impaired driving episodes.

RESULTS

A significantly higher percentage of impaired drivers reported past-year use of 8 of the 11 substances (including alcohol) examined when compared to other drug-involved offenders. Though symptoms of major depressive and posttraumatic stress disorders were similar, significantly more impaired drivers (49.6%) reported symptoms of generalized anxiety disorder than did other drug-involved offenders (35.0%). No differences in criminal histories were found. Nearly all (94.9%) impaired drivers reported driving under the influence of drugs in the past year; less than one-fourth reported driving under the influence of alcohol. Prescription opioids were the most prevalent substance type involved in impaired driving episodes (84.6%), followed by anti-anxiety medications (40.9%). Approximately one-third of impaired drivers reported driving under the influence of methamphetamine (33.9%), marijuana (31.5%), and alcohol (30.7%) in the past year.

CONCLUSIONS

Findings indicate that rural female impaired drivers may have more extensive substance use and mental health problems than other rural female drug-involved offenders. In addition, study results suggest that a recent history of impaired driving may serve as a marker for a more extensive substance use history. Other implications include that early identification of impaired drivers in at-risk groups may be an important opportunity to prevent future traffic injuries and fatalities.

The Prevalence of Substance Use Disorders among Community-based Adults with Legal Problems in the U.S

BACKGROUND

Current national prevalence estimates of DSM-5 diagnosed substance use disorders (SUDs) among adults with justice system involvement are lacking.

METHODS

This study drew from NESARC-III data (n = 36,309; 2012-2013), a nationally representative U.S. sample, to examine current and lifetime alcohol use disorder (AUD) and drug use disorder (DUD) diagnoses among adults reporting current or prior drug-related, alcohol-related, and general legal problems.

RESULTS

Adults reporting current alcohol-related legal problems were 22 times more likely to have a current AUD diagnosis (AOR = 22.0, 95% CI = 12.1; 40.1) and 15 times more likely to have had a lifetime AUD diagnosis (AOR = 15.2, 95% CI = 7.5; 30.9) than adults without alcohol-related legal problems. Adults with lifetime drug-related legal problems were 3-5 times more likely to have a current (AOR = 2.6, 95% CI = 2.1; 3.2) and lifetime (AOR = 5.1, 95% CI = 4.3; 6.1) DUD diagnosis, with stimulant use disorder being the most prevalent (AOR = 5.4, 95% CI = 4.5; 6.5). Adults with general legal problems were around 3 times more likely to have a current AUD (AOR = 3.2, 95% CI = 2.6; 4.0) or DUD (AOR = 3.5, 95% CI = 2.8; 4.4). Women with any type of legal problem were more likely to have SUD diagnoses than men.

CONCLUSIONS

SUD diagnoses are prevalent among adults reporting legal problems, particularly those involving alcohol. There is a continued need for community-based addiction prevention and intervention efforts, especially for women with justice system involvement.

Differences in alcohol cognitions, consumption, and consequences among first-time DUI offenders who co-use alcohol and marijuana

BACKGROUND

A significant portion of alcohol-related DUI offenders engage in co-use of alcohol and marijuana (AM). Given expanding marijuana legalization and the impaired driving risks associated with co-use, it is of increased importance to understand how characteristics of AM co-users compare to those who use alcohol only (AO) in order to inform DUI interventions and prevent recidivism.

METHODS

Participants were 277 first-time DUI offenders enrolled in a first-time DUI offender program across three locations. Using well-established measures, we evaluated differences in alcohol-related cognitions (positive expectancies and self-efficacy), frequency and quantity of alcohol consumption, and alcohol-related consequences between AO users and AM co-users by running a series of multivariate generalized linear models.

RESULTS

Compared to AO users, AM co-users reported lower self-efficacy to achieve abstinence and avoid DUI. Differences in abstinence self-efficacy largely explain higher relative rates of average and peak drinking quantity and higher odds of binge drinking among AM co-user. Despite lower self-efficacy and higher drinking quantity, there were no significant differences between AM and AO-users on alcohol-related consequences and past month reports of drinking and driving.

CONCLUSIONS

Our results provide preliminary evidence that DUI offenders who co-use alcohol and marijuana have higher alcohol use and lower self-efficacy than AO-users, and long-term consequences for this group should be monitored in future research. DUI programs may screen and identify co-users and consider tailoring their interventions to build self-efficacy to address the risks associated with AM co-use uniquely.

Characteristics of Prescription-Opioid-Impaired and Other Substance-Impaired Drivers in Rural Appalachian Kentucky

Previous studies have highlighted the prescription opioid epidemic in rural Appalachia and its associated risk behaviors; however, no studies have examined prescription-opioid-impaired driving as a consequence of this epidemic. The purpose of the present study was to describe prescription-opioid-impaired drivers in rural Appalachian Kentucky and examine how they are similar to and different from other substance-impaired drivers from the region. A sample of convicted DUI offenders from rural Appalachian Kentucky completed a confidential research interview focused on their substance use, mental health, and criminal activity. Prescription-opioid-impaired drivers (n = 33) were compared to other drug-impaired drivers (n = 29) and to alcohol-only-impaired drivers (n = 44). Overall, prescription-opioid-impaired drivers had a similar prevalence of illicit substance use and criminal activity, including impaired driving frequency, to other drug-impaired drivers, but had a higher prevalence of illicit substance use and more frequent impaired driving when compared to alcohol-only-impaired drivers. Study implications include the importance of comprehensive substance abuse assessment and treatment for DUI offenders and the need for tailored interventions for prescription-opioid-impaired and other drug-impaired drivers.

A descriptive analysis of drugged driving among rural DUI offenders

OBJECTIVE

Although driving under the influence (DUI) arrests occur at higher rates in rural areas and previous studies have shown more extensive drug use histories, little is known about how this relates to the prevalence and frequency of drugged driving. The present study examined drug use and drugged driving patterns among a sample of rural DUI offenders.

METHODS

Convicted rural DUI offenders (N = 118) completed a one-time, confidential research interview focused on drug use and drugged driving. A descriptive analysis was performed to examine the lifetime and past-year prevalence and frequency of drugged driving while under the influence of different drugs.

RESULTS

Approximately three fourths of the sample (77%) reported driving after illicit drug use in their lifetime and more than half of the sample (60%) reported doing so in the past year. Similar percentages of lifetime (86%) and past-year (81%) illicit drug users reported driving under the influence of at least one illicit drug. Illicit drug users reported a median of 240 lifetime and 16 past-year drugged driving episodes. Among those who reported ever driving after illicit drug use, marijuana (65%), prescription opioids (49%), and sedatives/tranquilizers/barbiturates (45%) were the most prevalent drugs involved in participants' drugged driving episodes.

CONCLUSIONS

Findings suggest that rural DUI offenders have extensive illicit drug use histories and frequently engage in drugged driving, posing a significant threat to public safety. Additional research on the characteristics of rural drugged drivers and their drug use and driving patterns is needed to inform the development of targeted interventions.

Drug Recognition Expert (DRE) examination characteristics of cannabis impairment

BACKGROUND

The Drug Evaluation and Classification Program (DECP) is commonly utilized in driving under the influence (DUI) cases to help determine category(ies) of impairing drug(s) present in drivers. Cannabis, one of the categories, is associated with approximately doubled crash risk. Our objective was to determine the most reliable DECP metrics for identifying cannabis-driving impairment.

METHODS

We evaluated 302 toxicologically-confirmed (blood Δ(9)-tetrahydrocannabinol [THC] ≥1μg/L) cannabis-only DECP cases, wherein examiners successfully identified cannabis, compared to normative data (302 non-impaired individuals). Physiological measures, pupil size/light reaction, and performance on psychophysical tests (one leg stand [OLS], walk and turn [WAT], finger to nose [FTN], Modified Romberg Balance [MRB]) were included.

RESULTS

Cases significantly differed from controls (p<0.05) in pulse (increased), systolic blood pressure (elevated), and pupil size (dilated). Blood collection time after arrest significantly decreased THC concentrations; no significant differences were detected between cases with blood THC <5μg/L versus ≥5μg/L. The FTN best predicted cannabis impairment (sensitivity, specificity, positive/negative predictive value, and efficiency ≥87.1%) utilizing ≥3 misses as the deciding criterion; MRB eyelid tremors produced ≥86.1% for all diagnostic characteristics. Other strong indicators included OLS sway, ≥2 WAT clues, and pupil rebound dilation. Requiring ≥2/4 of: ≥3 FTN misses, MRB eyelid tremors, ≥2 OLS clues, and/or ≥2 WAT clues produced the best results (all characteristics ≥96.7%).

CONCLUSIONS

Blood specimens should be collected as early as possible. The frequently-debated 5μg/L blood THC per se cutoff showed limited relevance. Combined observations on psychophysical and eye exams produced the best cannabis-impairment indicators.

Cannabis effects on driving lateral control with and without alcohol

BACKGROUND

Effects of cannabis, the most commonly encountered non-alcohol drug in driving under the influence cases, are heavily debated. We aim to determine how blood Δ(9)-tetrahydrocannabinol (THC) concentrations relate to driving impairment, with and without alcohol.

METHODS

Current occasional (≥1×/last 3 months, ≤3days/week) cannabis smokers drank placebo or low-dose alcohol, and inhaled 500mg placebo, low (2.9%)-THC, or high (6.7%)-THC vaporized cannabis over 10min ad libitum in separate sessions (within-subject design, 6 conditions). Participants drove (National Advanced Driving Simulator, University of Iowa) simulated drives (∼0.8h duration). Blood, oral fluid (OF), and breath alcohol samples were collected before (0.17h, 0.42h) and after (1.4h, 2.3h) driving that occurred 0.5-1.3h after inhalation. We evaluated standard deviations of lateral position (lane weave, SDLP) and steering angle, lane departures/min, and maximum lateral acceleration.

RESULTS

In N=18 completers (13 men, ages 21-37years), cannabis and alcohol increased SDLP. Blood THC concentrations of 8.2 and 13.1μg/L during driving increased SDLP similar to 0.05 and 0.08g/210L breath alcohol concentrations, the most common legal alcohol limits. Cannabis-alcohol SDLP effects were additive rather than synergistic, with 5μg/L THC+0.05g/210L alcohol showing similar SDLP to 0.08g/210L alcohol alone. Only alcohol increased lateral acceleration and the less-sensitive lane departures/min parameters. OF effectively documented cannabis exposure, although with greater THC concentration variability than paired blood samples.

CONCLUSIONS

SDLP was a sensitive cannabis-related lateral control impairment measure. During drive blood THC ≥8.2μg/L increased SDLP similar to notably-impairing alcohol concentrations. Despite OF's screening value, OF variability poses challenges in concentration-based effects interpretation.