The Association of Unfavorable Traffic Events and Cannabis Usage: A Meta-Analysis

Abstract

Background: In the last years were published many epidemiological articles aiming to link driving under the influence of cannabis (DUIC) with the risk of various unfavorable traffic events (UTEs), with sometimes contradictory results.Aim: The primary objective of this study was to analyze whether there is a significant association between DUIC and UTEs.Materials and Methods: We used two meta-analytical methods to assess the statistical significance of the effect size: random-effects model and inverse variance heterogeneity model.Results: Twenty-four studies were included in the meta-analysis. We obtained significant increases in the effect size for DUIC tested through blood analysis, with an odds ratio (OR) of 1.97 and a confidence interval (CI) between 1.35 and 2.87; death as an outcome, with an OR of 1.56 and a CI between 1.16 and 2.09; and case–control as the type of study, with an OR of 1.99 and a CI between 1.05 and 3.80. Publication bias was very high.Conclusion: Our analysis suggests that the overall effect size for DUIC on UTEs is not statistically significant, but there are significant differences obtained through subgroup analysis. This result might be caused by either methodological flaws (which are often encountered in articles on this topic), the indiscriminate employment of the term “cannabis use,” or an actual absence of an adverse effect. When a driver is found, in traffic, with a positive reaction suggesting cannabis use, the result should be corroborated by either objective data regarding marijuana usage (like blood analyses, with clear cut-off values), or a clinical assessment of the impairment, before establishing his/her fitness to drive.

Herbal Medicinal Products fromPassiflorafor Anxiety: An Unexploited Potential

“…The alternative to deal with these peculiarities related to herbal medicines is the determination of ADMET properties of pure constituents of the formulation, through in vitro tests, for example, Caco-2 cells, human liver microsomes, and cultured human hepatocytes [ 80 ]. In this context, the ADMET properties of the flavonoids iso-orientin, isovitexin, luteolin, apigenin, and kaempferol present in P. incarnata have been described in the literature [ 80 , 83 , 84 ].…”

“…Absorption processes are evaluated by blood-brain barrier (BBB) penetration and human intestinal absorption (HIA) methods that demonstrated high absorption through human intestine and side effects on absorption through BBB for iso-orientin, isovitexin, and luteolin. Apigenin and kaempferol showed positive values for both BBB and HIA [ 80 , 83 , 85 ]. The importance of a substance crossing the BBB is partially related to the required biological activity, and this is based on structural and physicochemical characteristics, such as lipophilicity, molecular size, desolvation potential, pKa-to-charge ratio, and hydrogen bond [ 80 , 86 , 87 ].…”

“…Among the previously mentioned flavonoids, only iso-orientin and isovitexin, have low CYP inhibitory promiscuity. However, all of them were nonsubstrate for all CYP450 substrates (2C9, 2D6), and most of them inhibited most of the CYP450 inhibitors (2C9 and 2D6) [ 80 , 83 , 85 ]. The inhibition of CYP450 isoforms is closely related to the metabolism of a substance and can lead to increased toxicity [ 85 ].…”

Early Evidence on Recreational Marijuana Legalization and Traffic Fatalities

“…Bondallaz et al () review this literature and find that marijuana use impairs driving primarily by increasing lane weaving and decreasing the mean distance between vehicles. However, they also find significant discrepancies between studies and note the “the neurobiological mechanisms underlying the effects … remain poorly understood, as does the correlation between body fluids concentrations and psychoactive effects of THC.” Hostiuc et al () performed a meta‐analysis of epidemiological studies of marijuana consumption and driving performance and found a statistically insignificant effect size and substantial bias favoring the publication of studies that showed a positive association between marijuana consumption and traffic accidents.…”

Six policy lessons relevant to cannabis legalization

“…Illegal cannabis smoked on college campuses in the 1970s had 3-5% THC, whereas legal cannabis sold in Washington State today averages 20% THC (28). Higher potency is concerning because of greater risk of adverse psychiatric effects and greater potential to transition light users into daily users and cannabis use disorders (29)(30)(31). For example, a study in the Netherlands found first-time drug treatment admissions for cannabis rose following increasing cannabis potency (32).…”