Correlates of Marijuana Drugged Driving and Openness to Driving While High: Evidence from Colorado and Washington

Aims

A potential unintended consequence of legalizing recreational marijuana is increased marijuana-related driving impairment. Some states where recreational marijuana is legal have begun implementing interventions to mitigate driving under the influence (DUI) of marijuana, including media campaigns to increase knowledge about DUI laws. However, little is known about the associations between knowledge of DUI laws and marijuana DUI behavior. In this study, we provide new data from a survey of marijuana users in Colorado and Washington to examine associations between marijuana drugged driving and two potential behavioral precursors of marijuana DUI. We also explore other factors that may influence marijuana DUI.

Methods

Data are from an online survey of marijuana users in Colorado and Washington. Respondents who reported any marijuana use in the past 30 days (n = 865) served as the analytic sample. We examined prevalence of two behavioral outcomes: (1) any driving of a motor vehicle while high in the past year and (2) driving a motor vehicle within 1 hour of using marijuana 5 or more times in the past month. Additional outcomes measuring willingness to drive while high were also assessed. Logistic regressions were used to estimate each outcome as a function of two multi-item scales measuring knowledge of the legal consequences of driving high and perceptions that driving while high is not safe. Additional covariates for potential confounders were included in each model.

Results

Prevalence of past-year driving while under the influence of marijuana was 43.6% among respondents. The prevalence of driving within 1 hour of using marijuana at least 5 times in the past month was 23.9%. Increased perception that driving high is unsafe was associated with lower odds of past-year marijuana DUI (OR = 0.31, P < 0.01) and lower past-month odds of driving 5 or more times within 1 hour of using marijuana (OR = 0.26, P < 0.01). Increased knowledge of marijuana DUI laws was also associated with lower odds of each of these outcomes (OR = 0.63, P < 0.01, OR = 0.69, P = 0.02, respectively). Post-estimation Wald tests confirmed the negative associations with marijuana DUI were greater in magnitude for safety perceptions than knowledge of DUI laws. Increased perceptions that driving while high is unsafe was associated with significantly lower willingness to drive after using marijuana while increased knowledge of marijuana DUI laws was not associated with these outcomes.

Conclusions

Despite recent interventions targeting public awareness of the legal consequences of marijuana DUI, our results suggest that knowledge of these laws is a weaker predictor of DUI behavior than perceptions that driving high is unsafe. In addition, safety perceptions predict decreased openness to driving high while knowledge of DUI laws was not associated with openness. These findings suggest that interventions for reducing the incidence of marijuana DUI are likely to be more successful by targeting safety perceptions related to marijuana DUI rather than knowledge of DUI laws. We caution that because these data are limited to an online convenience sample, results may not be generalizable beyond our sample.     

Effect of Glyphosate on Intact Bean Plants (Phaseolus vulgaris L.) and Isolated Cells

Whole bean (var. “Eastern Butterwax”) plants and isolated cells were used to investigate possible mechanisms of action of glyphosate [N-(phosphonomethyl)glycine]. Results showed that glyphosate was quickly absorbed by the whole plant but not by individual cells and that it caused a rapid reduction in leaf dry matter accumulation, leaf expansion, leaf angle, and stomatal aperture without affecting the water status of the plant. Glyphosate also caused a rapid reduction in cellular uptake of ⁸⁶Rb and ³²P which preceded its detrimental effects on photosynthesis, RNA and protein synthesis, and respiration of isolated cells. This reduction in ion absorption was not due to a loss of membrane integrity, decrease in energy supply or chelation of ions. It was concluded that glyphosate was directly inhibiting the ion absorption process of bean leaf cells.     

Selection and characterization of ethionine-resistant alfalfa (Medicago sativa L.) cell lines

Summary Diploid alfalfa (HG2), capable of plant regeneration from tissue culture, was used to select variant cell lines resistant to growth inhibition due to ethionine (an analog of methionine). Approximately 10⁷ suspension-cultured cells were mutagenized with methane sulfonic acid ethylester and then plated in solid media containing ethionine. Callus colonies formed on media with 0.02 mM ethionine. Of the 124 cell lines recovered, 91 regenerated plants. After six months growth on media without ethionine, 15 of 110 cell lines of callus grew significantly better than HG2 on 1 mM ethionine. Several ethionine-resistant callus cultures were also resistant to growth inhibition due to the addition of lysine + threonine to the media. High concentrations, relative to unselected HG2 callus, of methionine, cysteine, cystathionine, and glutathione were found in some, but not all, ethionine-resistant callus cultures. Cell line R32, which had a ca. tenfold increase in soluble methionine, had a 43% increase in total free amino acids and a 40% increase in amino acids in protein as compared to unselected HG2 callus. Relative amounts of each amino acid in protein were the same in both.Abbreviation LT lysine + threonine in equimolar concentration     

Characterization of alternative molecular forms of xanthine oxidase in the mouse

1. Two major forms of xanthine oxidase are demonstrated for the mouse. On polyacrylamide-gel electrophoresis the duodenal form migrates faster towards the anode than that of the liver. Both forms also differ in their (NH(4))(2)SO(4) precipitation patterns and sucrose-density-gradient molecular-weight determinations. 2. The liver form is fully converted into the duodenal form by incubation at 37 degrees C with 2.5mg of crude trypsin/ml for 1(1/2)h, without loss of activity. The trypsin-treated liver form behaves like the normal duodenal form as characterized by electrophoresis, (NH(4))(2)SO(4) precipitation patterns, and sucrose-density-gradient molecular-weight determinations. 3. Partial conversion is also brought about by purified trypsin and chymotrypsin, but not with beta-carboxypeptidase or lipase. The conversion is inhibited by soya-bean trypsin inhibitor. 4. In embryo mice the duodenal form is similar to the liver form on electrophoresis. 5. These studies indicate, as might be expected, that the duodenal form is a modified version of the liver enzyme, probably caused by proteolytic alteration.     

Effect of Age and Sex on Human Drug Metabolism

The capacity of inpatients in a geriatric hospital to metabolize drugs was measured. The mean plasma half-life values with antipyrine and with phenylbutazone were found to be 45% and 29% greater respectively in patients than in young controls. When women alone were considered the half-life of antipyrine was 78% longer in the elderly group. In a number of elderly individuals the rate of metabolism of these two drugs was found to be extremely slow. This decreased ability to metabolize drugs may contribute to the known high incidence of adverse drug reactions in the elderly.Within the control group a significant sex difference in the rate of antipyrine metabolism was found, the mean half-life being 30% longer in the males. It is clear from these results that the age and sex of subjects must be taken into account in studies of human drug metabolism.     

Acute effects of thoracic irradiation on lung function and structure in awake sheep

To investigate the acute physiological and structural changes after lung irradiation, the effects of whole-lung irradiation were investigated in fourteen sheep. Ten sheep were prepared with vascular and chronic lung lymph catheters, then a week later were given 1,500 rad whole-lung radiation and monitored for 2 days. Four sheep were given the same dose of radiation and were killed 4 h later for structural studies. Lung lymph flow increased at 3 h after radiation (14.6 +/- 2.1 ml/h) to twice the base-line flow rate (7.5 +/- 1.3), with a high lymph-to-plasma protein concentration. Pulmonary arterial pressure increased twofold from base line (18 +/- 1.6 cmH2O) at 2 h after radiation (33 +/- 3.8). Cardiac output and systemic pressure in the aorta did not change after lung radiation. Arterial O2 tension decreased from 85 +/- 3 to 59 +/- 4 Torr at 1 day after radiation. Lymphocyte counts in both blood and lung lymph decreased to a nadir by 4 h and remained low. Thromboxane B2 concentration in lung lymph increased from base line (0.07 +/- 0.03 ng/ml) to peak at 3 h after radiation (8.2 +/- 3.7 ng/ml). The structural studies showed numerous damaged lymphocytes in the peripheral lung and bronchial associated lymphoid tissue. Quantitative analysis of the number of granulocytes in peripheral lung showed no significant change (base line 6.2 +/- 0.8 granulocytes/100 alveoli, 4 h = 10.3 +/- 2.3). The most striking change involved lung airways. The epithelial lining of the majority of airways from intrapulmonary bronchus to respiratory bronchiolus revealed damage with the appearance of intracellular and intercellular cell fragments and granules. This new large animal model of acute radiation lung injury can be used to monitor physiological, biochemical, and morphological changes after lung radiation. It is relevant to the investigation of diffuse oxidant lung injury as well as to radiobiology per se.