[Cannabis and driving: the situation in Europe]

In Europe, three million people consume cannabis every day. Investigations showed that more than two thirds of drug users drive after having smoked cannabis. Epidemiological studies show that between 0.5% and 8.2% of the general driving population is positive for cannabis. For drivers wounded or deceased as a result of an accident, the percentage varies respectively from 3.3% to 10% and from 2.2% to 8.4%. Finally, very high percentages are found in the studies which analysed the presence of drugs in drivers suspected of driving under the influence of drugs: more than 50% in Austria, Belgium, Germany, Switzerland and the United Kingdom. Six European countries adopted an analytical or 'per se' legislation and the cut-offs vary between 0.3 and 2 ng/mL THC. In the Netherlands, experimental studies carried out after administration of cannabis clearly showed the impairing effects, in particular in the event of simultaneous consumption of cannabis and alcohol. Various research projects financed by the European Union studied the epidemiologic aspects (IMMORTAL), detection by psychotechnical tests (CERTIFIED) and roadside drug detection (ROSITA and ROSITA-2).

Driving under the influence of drugs -- evaluation of analytical data of drugs in oral fluid, serum and urine, and correlation with impairment symptoms

A study was performed to acquire urine, serum and oral fluid samples in cases of suspected driving under the influence of drugs of abuse. Oral fluid was collected using a novel sampling/testing device (Dräger DrugTest System). The aim of the study was to evaluate oral fluid and urine as a predictor of blood samples positive for drugs and impairment symptoms. Analysis for cannabinoids, amphetamine and its derivatives, opiates and cocaine was performed in urine using the Mahsan Kombi/DOA4-test, in serum using immunoassay and gas chromatography-mass spectrometry (GC-MS) confirmation and in oral fluid by GC-MS. Police and medical officer observations of impairment symptoms were rated and evaluated using a threshold value for the classification of driving inability. Accuracy in correlating drug detection in oral fluid and serum were >90% for all substances and also >90% in urine and serum except for THC (71.0%). Of the cases with oral fluid positive for any drug 97.1% of corresponding serum samples were also positive for at least one drug; of drug-positive urine samples this were only 82.4%. In 119 of 146 cases, impairment symptoms above threshold were observed (81.5%). Of the cases with drugs detected in serum, 19.1% appeared not impaired which were the same with drug-positive oral fluid while more persons with drug-positive urine samples appeared uninfluenced (32.7%). The data demonstrate that oral fluid is superior to urine in correlating with serum analytical data and impairment symptoms of drivers under the influence of drugs of abuse.

Drug and alcohol use among drivers admitted to a Level-1 trauma center

The purpose of this research was to determine the incidence and prevalence of drug use, alcohol use, and the combination of drug and alcohol use among motor vehicle crash (MVC) victims admitted to a Level-1 trauma center. In a 90-day study, nearly two-thirds of trauma center admissions were victims of motor vehicle crashes. Blood and urine was collected from 168 MVC victims of whom 108 were identified as the driver in the crash. Toxicology results indicated that 65.7% of drivers tested positive for either commonly abused drugs or alcohol. More than half of the drivers tested positive for drugs (50.9%) other than alcohol, with one in four drivers testing positive for marijuana use. About one-third of those using drugs had also been drinking, but alcohol was detected in only 30.6% of all injured drivers. Within the total MVC patient pool, passenger drug/alcohol use was equivalent to the driver population; however, injured pedestrians had higher rates of alcohol only than other MVC victims. There were no significant differences in drug and alcohol use between MVCs and trauma admissions of other causes. Of the patients with positive toxicology results, less than half (42%) were referred for evaluation for substance abuse disorders.

Drugs in oral fluid

As part of the European project, Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing, otherwise known as IMMORTAL (Deliverable R4.2), the University of Glasgow was required to analyse 1396 oral fluid samples, collected from drivers, for a wide range of drugs. A previously described method to include 49 drugs and metabolites was used. To include cannabis in the study a separate extraction method was required because of interferences caused by the collection device. The study group included drivers who were stopped at random and participation was entirely voluntary. The results showed that out of the 1396 samples tested, 16.8% were positive for at least one drug. In the majority of positive cases (85%), monodrug use was found and the most commonly detected drug was 3,4-methylenedioxymethamphetamine. This study showed that a significant number of the driving population are positive for at least one drug.

Impaired perception of self-motion (heading) in abstinent ecstasy and marijuana users

RATIONALE

Illicit drug use can increase driver crash risk due to loss of control over vehicle trajectory. This study asks, does recreational use of +/-3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) and tetrahydrocannabinol (THC; marijuana) impair cognitive processes that help direct our safe movement through the world?

OBJECTIVE

This study assesses the residual effects of combined MDMA/THC use, and of THC use alone, upon perceived trajectory of travel.

METHODS

Perception of self-motion, or heading, from optical flow patterns was assessed using stimuli comprising random dot ground planes presented at three different densities and eight heading angles (1, 2, 4 and 8 degrees to the left or right). On each trial, subjects reported if direction of travel was to the left or the right.

RESULTS

Results showed impairments in both drug groups, with the MDMA/THC group performing the worst.

CONCLUSIONS

The finding that these psychoactive agents adversely affect heading perception, even in recently abstinent users, raises potential concerns about MDMA use and driving ability.

Drug and drink driving by university students: an exploration of the influence of attitudes

The present study aimed to gather information on drug and alcohol use, the prevalence of drink and drug driving and attitudes to both in an undergraduate university cohort (n = 275). Further, the study aimed to contribute information to aid intervention program development by determining predictors of drink and drug driving behavior. The study examines both drug and alcohol use and the influence of attitudes toward driving while under the influence of alcohol and/or drugs. Results indicated that significant proportions of university students are engaging in the risk-taking behavior of driving under the influence of drugs (25%), alcohol (14%), or both (8%). The results suggest that attitudes toward driving under the influence of alcohol and/or drugs are a strong predictor of engaging in the behavior. Peer influence emerged as a major aspect of attitudes. The results of this study provide an important beginning to understanding drink and drug driving and the influence of attitudes in the university student body.

Epidemiology of alcohol and other drug use among motor vehicle crash victims admitted to a trauma center

The objectives of this research were to (1) determine the incidence and prevalence of alcohol and other drug use among motor vehicle crash (MVC) victims admitted to a regional Level-I trauma center, and (2) to examine the utility of using a rapid point-of-collection (POC) drug-testing device to identify MVC patients with drug involvement. Blood and urine specimens were routinely collected per clinical protocol for each MVC victim at the time of admission. Blood alcohol concentration (BAC) levels were determined per standard clinical protocol. Clinical urine specimens were routinely split so that a POC drug-testing device for the detection of commonly abused drugs (Marijuana, Cocaine, Amphetamines, Methamphetamines, and Opiates) could be compared to that of the standard hospital laboratory analysis of each urine specimen (which also included Barbiturates and Benzodiazepines). In the six-month period of this study, nearly two-thirds of trauma center admissions were victims of motor vehicle crashes. During this time, blood and urine was collected from 322 MVC victims. Toxicology results indicated that 59.3% of MVC victims tested positive for either commonly abused drugs or alcohol. More patients tested positive for drug use than tested positive for alcohol, with 33.5% testing positive for drug use only, 15.8% testing positive for alcohol use only, and 9.9% testing positive for both drugs and alcohol. Less than half (45.2%) of the substance-abusing patients in this study would have been identified by an alcohol test alone. After alcohol, marijuana and benzodiazepines were the most frequently detected drugs. Point of collection (POC) test results correlated well with laboratory results and provide important information to initiate rapid intervention/treatment for substance use problems among injured patients.