Toward a More Parsimonious Approach to Drug Recognition Expert Evaluations

Porath-Waller, Amy J.; Beirness, Douglas James; Beasley, Erin

doi:10.1080/15389580903191617

Cited by 11 publications

(13 citation statements)

References 6 publications

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“…These findings appear in line with previous studies that have reported a relation between impairment on the SFST and presence of THC in blood. A study that assessed which signs of the Drug Evaluation and Classification evaluations predicted various drug categories (including cannabis) at best showed that OLS contributed significantly to the prediction, but HGN and WAT did not (Porath-Waller et al 2009). Papafotiou et al (2005a) assessed SFST performance in 40 healthy participants who received low and high doses of THC in a placebo-controlled study.…”

Section: Discussionmentioning

confidence: 99%

A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid

et al. 2012

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RationaleStandardized Field Sobriety Tests (SFST) and oral fluid devices are used to screen for driving impairment and roadside drug detection, respectively. SFST have been validated for alcohol, but their sensitivity to impairment induced by other drugs is relatively unknown. The sensitivity and specificity for Δ9-tetrahydrocannabinol (THC) of most oral fluid devices have been low.ObjectiveThis study assessed the effects of smoking cannabis with and without alcohol on SFST performance. Presence of THC in oral fluid was examined with two devices (Dräger Drug Test® 5000 and Securetec Drugwipe® 5).MethodsTwenty heavy cannabis users (15 males and 5 females; mean age, 24.3 years) participated in a double-blind, placebo-controlled study assessing percentage of impaired individuals on the SFST and the sensitivity of two oral fluid devices. Participants received alcohol doses or alcohol placebo in combination with 400 μg/kg body weight THC. We aimed to reach peak blood alcohol concentration values of 0.5 and 0.7 mg/mL.ResultsCannabis was significantly related to performance on the one-leg stand (p = 0.037). Alcohol in combination with cannabis was significantly related to impairment on horizontal gaze nystagmus (p = 0.029). The Dräger Drug Test® 5000 demonstrated a high sensitivity for THC, whereas the sensitivity of the Securetec Drugwipe® 5 was low.ConclusionsSFST were mildly sensitive to impairment from cannabis in heavy users. Lack of sensitivity might be attributed to tolerance and time of testing. SFST were sensitive to both doses of alcohol. The Dräger Drug Test® 5000 appears to be a promising tool for detecting THC in oral fluid as far as correct THC detection is concerned.

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Section: Discussionmentioning

confidence: 99%

A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid

et al. 2012

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“…Based on scientific and medical knowledge about the known signs and symptoms associated with various drugs, the DEC program is a systematic and standardized 12-step procedure used by trained law enforcement officers, known as drug recognition experts (DREs), to recognize and evaluate behaviors and physiological indicators associated with 7 different drug categories: Central nervous system (CNS) depressants, inhalants, dissociative anesthetics, cannabis, CNS stimulants, hallucinogens, and narcotic analgesics. The results of the 12-step protocol, when corroborated by toxicological evidence of drug use, provide sufficient evidence to proceed with drug-impaired driving charges (Beirness and Porath 2017;Porath-Waller et al 2009).…”

Section: Introductionmentioning

confidence: 87%

“…The officer then assesses these data to determine whether the subject is impaired and which drug category or categories are most likely responsible for the impairment. The amount of information is extensive and some have questioned whether the number of pieces of information collected is too large to reasonably consider in rendering an opinion about the class of drug involved (Schechtman and Shinar and Schechtman 2005) and that it may be possible to initially focus on a core set of measures from the evaluation without significantly compromising accuracy (Porath-Waller and Beirness 2010;Porath-Waller et al 2009). Because the DEC evaluation provides evidence of impairment and drug influence, it is important that the opinion of the evaluating officer in terms of drug category is accurate.…”

Section: Introductionmentioning

confidence: 99%

“…Research suggests that it may be possible to identify a core set of measures from DEC evaluations that can be used to guide opinions about drug category/categories without significantly compromising accuracy (Porath-Waller and Beirness 2010;Porath-Waller et al 2009). Using data from 742 completed evaluations from Canada, Porath-Waller and colleagues (2009) reported that DREs can focus on a limited set of key signs and symptoms when determining the category of drug used by a suspected drug-impaired driver without significantly compromising the accuracy of their evaluations.…”

Section: Introductionmentioning

confidence: 99%

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Predicting categories of drugs used by suspected drug-impaired drivers using the Drug Evaluation and Classification Program tests

Porath

Beirness

2019

Traffic Injury Prevention

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Objective: The purpose of this study was to statistically determine which combination(s) of drugrelated signs and symptoms from the Drug Evaluation and Classification (DEC) protocol best predict the drug category used by the suspected drug-impaired driver. Methods: Data from 1,512 completed DEC evaluations of suspected impaired drivers subsequently found to have ingested central nervous system (CNS) depressants, CNS stimulants, narcotic analgesics, and cannabis were analyzed using a multinomial logistic regression procedure. A set of evaluations completed on drug-free subjects was also included. The relative importance of clinical, behavioral, and observational measures in predicting drug categories responsible for impairment was also examined. Results: Thirteen drug-related indicators were found to significantly contribute to the prediction of drug category, including being under the care of a doctor or dentist, condition of the eyes, condition of the eyelids, mean pulse rate, assessment of horizontal gaze nystagmus (HGN), convergence, performance on the One Leg Stand (OLS) Test, eyelid tremors, pupil size in darkness, reaction to light, presence of visible injection sites, systolic blood pressure, and muscle tone. Indicators related to the appearance and physiological response of the eye contributed the most to the prediction of drug category, followed closely by clinical indicators and performance on the psychophysical tests. Conclusions: The findings from this study suggest that drug recognition experts (DREs) should be careful to review a set of key signs and symptoms when determining the category of drug used by suspected drug-impaired drivers. Drug use indicators related to the appearance and physiological response of the eye were found to contribute the most to the prediction of the drug category responsible for the impairment. These results could help form the basis of a core set of indicators that DREs could initially consult to form their opinion of drug influence. This in turn may enhance the validity, effectiveness, and efficiency of drug detection and identification by DREs and lead to a more effective and efficient DEC program, improved enforcement of drugimpaired driving, and greater acceptance of the DEC program by the courts.

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“…10 Recent data suggest that approximately 5% of Canadian drivers/adults report driving after cannabis use in the past year. 39 Large-scale epidemiological studies using different methodologies (e.g., retrospective epidemiological and case control studies) have found that cannabis use acutely increases the risk of motor vehicle accident (MVA) involvement and fatal crashes among drivers. 40,41 Recent reviews have found the increase in risk to be approximately 1.5-3.0, an increase which is substantially lower, however, than that in alcoholimpaired drivers.…”

Section: Cannabis Use and Drivingmentioning

confidence: 99%

Lower Risk Cannabis Use Guidelines for Canada (LRCUG): A Narrative Review of Evidence and Recommendations

Fischer

Jeffries

Hall

et al. 2011

Can J Public Health

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ore than 10% of the general adult population in Canada report use (largely recreational) of cannabis in the past year, the highest use rate of any illegal drug. 1 Use rates among adolescents and young adults (i.e., 16-29 years of age) range from 26-46%. While cannabis use-like all psychoactive substance use-is associated with possible harms, it is currently governed by a policy of categorical prohibition in Canada. 2 Specifically, the current Controlled Drugs and Substances Act (CDSA) makes 'simple cannabis possession' a criminal offense; 45,000 Canadians (or 1-2% of all estimated past-year users) are arrested annually for this offense. 3 Similarly, current prevention and treatment efforts predominantly aim at abstinence. The policy approach to cannabis is fundamentally different from current approaches to other popular drugs like alcohol, where a public health approach instead focuses on high-risk users, risky use practices and settings, and especially on modifiable risk factors, to reduce harms to individuals and society. 4 Given that the majority of harms related to cannabis use appear to occur in selected highrisk users or in conjunction with high-risk use practices, a similar public health-oriented approach to cannabis use should be considered. 5 Such an approach would rely on targeted and healthoriented interventions mainly aimed at those users at high risk for harms, and not criminalization of use-and its limited effectiveness and undesirable side-effects-as the main intervention paradigm, therefore increasing benefits for society. 2 Recent surveys consistently show that a majority of Canadians (i.e., >50%) support the decriminalization of personal cannabis use. 6 An important educational tool in a public health-oriented alcohol policy are so-called 'Low Risk Drinking Guidelines'. 7 These use scientific evidence to provide guidelines on practices or patterns of alcohol use that substantially reduce the risks of experiencing acute and long-term harms. 7 Similarly, below we summarize data on key modifiable factors that may influence harmful outcomes from cannabis use, with a view to formulating 'Lower Risk Cannabis Use Guidelines' (LRCUG) as an evidence-based public health policy tool to reduce harms from (non-medical) cannabis use in the Canadian population. Early onset of use Longitudinal studies suggest that early onset of cannabis use (e.g., <16 years) is associated with a higher likelihood of a variety of problems. For example, Lynskey followed a sample of 1,601 high school students, and found that early regular cannabis use (weekly use at age 15) increased the risk of early school leaving. 8 In a New Zealand birth cohort of 1,003 young people, cannabis use at early age was significantly associated with multiple adverse outcomes in later life, including lower rates of university degree completion. 9

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Toward a More Parsimonious Approach to Drug Recognition Expert Evaluations

Cited by 11 publications

References 6 publications

A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid

A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid

Predicting categories of drugs used by suspected drug-impaired drivers using the Drug Evaluation and Classification Program tests

Lower Risk Cannabis Use Guidelines for Canada (LRCUG): A Narrative Review of Evidence and Recommendations

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