Driving under the influence: a multi-center evaluation of vehicular crashes in the era of cannabis legalization

Abstract

BackgroundEleven states have instituted laws allowing recreational cannabis use leading to growing public health concerns surrounding the effects of cannabis intoxication on driving safety. We hypothesized that after the 2016 legalization of cannabis in California, the use among vehicular injury patients would increase and be associated with increased injury severity.MethodsSan Diego County’s five adult trauma center registries in were queried from January 2010 to June 2018 for motor vehicle or motorcycle crash patients with completed toxicology screens. Patients were stratified as toxicology negative (TOX−), positive for only THC (THC+), only blood alcohol >0.08% (ETOH+), THC+ETOH, or THC+ with any combination with methamphetamine or cocaine (M/C). County medical examiner data were reviewed to characterize THC use in those with deaths at the scene of injury.ResultsOf the 11,491 patients identified, there were 61.6% TOX−, 11.7% THC+, 13.7% ETOH+, 5.0% THC+ETOH, and 7.9% M/C. THC+ increased from 7.3% to 14.8% over the study period and peaked at 14.9% post-legalization in 2017. Compared with TOX− patients, THC+ patients were more likely to be male and younger. THC+ patients were also less likely to wear seatbelts (8.5% vs 14.3%, p<0.001) and had increased mean Injury Severity Score (8.4±9.4 vs 9.0±9.9, p<0.001) when compared with TOX− patients. There was no difference in in-hospital mortality between groups. From the medical examiner data of the 777 deaths on scene, 27% were THC+.DiscussionTHC+ toxicology screens in vehicular injury patients peaked after the 2016 legalization of cannabis. Public education on the risks of driving under the influence of cannabis should be a component of injury prevention initiatives.Level of evidenceIII, Prognostic

Increased identification of cannabis use among drivers involved in motor vehicle collisions using an expanded cannabis inventory

“…Previously reported averages among 10 injured ED patients in U.S. hospitals (15% by biosample, 19.7% by self‐report) are generally lower than what we discovered in our study, although we did not conduct a formal comparison 11 . Using content that includes different types of consumption will allow research studies to characterize use patterns accurately.…”

The Impact of Recreational Cannabis Legalization on Cannabis Use and Associated Outcomes: A Systematic Review

“…94,95 Further, a California-based study examining THC toxicology screens in motor vehicle accident patients, did find a significant increase in positive screens, but this increase was not associated with implementation of RCL. 96 However, three studies suggest a negative impact of RCL, as one U.S. study found both RCL states and their neighboring states had an increase in motor vehicle fatalities immediately following RCL. 97 Additionally, a Canadian study did find a significant increase in moderately injured drivers with cannabis positive blood screens post-RCL.…”

Effects of Cannabis Legalization on Road Safety: A Literature Review

“…Of the 29 articles included in this review, eight focused on the legalization of medical cannabis [22][23][24][25][26][27][28][29], with respect to recreational cannabis, there were 13 papers that addressed the impact of its legalization with respect to traffic accidents [3,[30][31][32][33][34][35][36][37][38][39][40][41], two papers included both medical and recreational cannabis [42,43], and seven papers discussed the decriminalization and legalization of cannabis in general [8,[43][44][45][46][47][48].…”

“…With regard to the samples, it should be noted that these were mainly made up of men, except for two studies with a greater presence of women [3,23], with a minimum age of 14 years [26,48]. Among the selected papers were a large number of studies that, in addition to collecting data on cannabis use, also reported on alcohol use [3,8,[22][23][24][25]28,29,36,37,[44][45][46].…”

“…After legalization, the trend reversed, with an increase in the number of cases, although this change was not significant. Steinemann et al [36] analyzed traffic crashes occurring pre-and post-MCL in Hawaii, concluding that crashes resulting in death nearly tripled from 5.5% between 1993 and 2000 to 16.3% between 2011 and 2015. However, they found no change in the prevalence of alcohol or other substances, such as methamphetamine.…”