The incidence of drugs in drivers killed in Australian road traffic crashes

The prevalence of drugs in motor vehicle accidents and traffic violations in Shanghai and neighboring cities

The objective of this study was to determine the prevalence of psychoactive drug use among motor vehicle drivers in Shanghai and its neighboring cities. We selected 10,002 drivers involved in a traffic accident or violation between 2007 and 2008 in Shanghai, Suzhou and Wuxi. We checked for the presence of psychoactive drugs from blood samples using liquid chromatography tandem mass spectrometry (LC-MS-MS). Of the 10,002 drivers, 10.5% tested positive for drugs (excluding alcohol). Cold medicines were the most frequently detected drugs including chlorpheniramine (4.78%), pseudoephedrine (2.15%) and paracetamol (1.32%). The use of multiple cold medicines was common. Illegal drugs such as methamphetamine (0.15%), ketamine (0.03%) and MDMA (0.01%) were also detected. The prevalence of psychoactive drugs among drivers involved in traffic accidents or violations in Shanghai and its neighboring cities was lower compared to previous reports in Europe. Furthermore, cannabis--which has been reported to be the most widely used psychoactive drug after alcohol--was not commonly encountered among Shanghai drivers.

[Vulnerability to sexually transmitted diseases/AIDS and use of psychoactive drugs by truck drivers]

A cross-sectional epidemiological descriptive study with the purpose of identify the demographic characteristics, health aspects and life style, vulnerability to Sexually Transmitted Diseases/AIDS amongst long distance truck drivers were applied to 50 drivers from supply center of Campinas (fruit, vegetable, product wholesale market). The outcomes showed that almost all drivers interviewed were men, the majority were married, had kids, low study level and fewer than 40 years old. 70% reported abuse psychoactive drugs. The majority was aware of the importance of using condoms with casual partners; 94% reported relationship with casual partners and just 6% never used condoms. Although the small sample analyzed, the results suggests that must be implemented health promotion actions and illness prevention public politics, including the development of customized educational interventions with in this professional group.

The relationship between benzodiazepine use and traffic accidents: A systematic literature review

In many countries, benzodiazepines are the most commonly used and misused psychoactive medicinal drugs. Results of epidemiological studies investigating the association between benzodiazepine use and traffic accidents seem to be inconclusive or inconsistent at first sight. However, the outcome of epidemiological studies may be influenced by several methodological factors like study design, study population, exposure measurement, outcome definitions and possible confounders. Our objective was to conduct a systematic literature review of epidemiological studies that investigated the association between benzodiazepine use and traffic accidents, including related outcomes like culpability and injury or accident severity. We searched EMBASE, PubMed and Forensic Science Abstracts 3/0 (FORS) for references included in these databases at 1 June 2009 using the term 'benzodiazepines' in combination with 'driving performance' or 'accident risk' or 'traffic accident'. For inclusion in this review, the study design had to be comparative, include road users involved in accidents and provide specific data about benzodiazepines. Sixty-six studies were included in the review. The study populations varied from the general (driving) population, accident-involved road users with or without injury and persons admitted to a hospital to fatally injured accident-involved drivers. Exposure assessment was performed by using toxicological results, prescription data or questionnaires. The divergent study populations and comparison groups and the variety of methods used to express the outcome of interest hampered comparison between results. Evidence is growing that exposure to benzodiazepines is related to increased accident risk. The literature indicates that the greatest accident risk is associated with the use of long half-life benzodiazepines, increasing dosage and the first few weeks of use of benzodiazepines. Clear evidence of increased culpability associated with benzodiazepine use is scarce. More research has to be done to elucidate the relationship between benzodiazepine use and injury severity.

Typologies of cannabis users and associated characteristics relevant for public health: a latent class analysis of data from a nationally representative Canadian adult survey

Cannabis is the most prevalently used illicit drug in Canada. Current policy consists primarily of universal use prohibition rather than interventions targeting specific risks and harms relevant for public health. This study aimed to identify distinct groups of cannabis users based on defined use characteristics in the Canadian population, and examine the emerging groups' associations with differential risk and harm outcomes. One thousand three hundred and three current (i.e. use in the past three months) cannabis users, based on data from the representative cross-sectional 2004 Canadian Addiction Survey (N = 13,909), were statistically assessed by a 'latent class analysis' (LCA). Emerging classes were examined for differential associations with socio-demographic, health and behavioral indicators on the basis of chi-square and analysis of variance techniques. Four distinct classes based on use patterns were identified. The class featuring earliest onset and highest frequency of use [22% of cannabis user sample or 2.2% (95% confidence interval (CI) = 1.8-2.7%) of the Canadian adult population] was disproportionately linked to key harms, including other illicit drug use, health problems, cannabis use and driving, and cannabis use problems. A public health framework for cannabis use is needed in Canada, meaningfully targeting effective interventions towards the minority of users experiencing elevated levels of risks and harms.

First nationwide study on driving under the influence of drugs in Switzerland

In Switzerland, a two-tier system based on impairment by any psychoactive substances which affect the capacity to drive safely and zero tolerance for certain illicit drugs came into force on 1 January 2005. According to the new legislation, the offender is sanctioned if Delta(9)-tetrahydrocannabinol THC is >or=1.5ng/ml or amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), cocaine, free morphine are >or=15ng/ml in whole blood (confidence interval+/-30%). For all other psychoactive substances, impairment must be proven in applying the so-called "three pillars expertise". At the same time the legal blood alcohol concentration (BAC) limit for driving was lowered from 0.80 to 0.50g/kg. The purpose of this study was to analyze the prevalence of drugs in the first year after the introduction of the revision of the Swiss Traffic Law in the population of drivers suspected of driving under the influence of drugs (DUID). A database was developed to collect the data from all DUID cases submitted by the police or the Justice to the eight Swiss authorized laboratories between January and December 2005. Data collected were anonymous and included the age, gender, date and time of the event, the type of vehicle, the circumstances, the sampling time and the results of all the performed toxicological analyses. The focus was explicitly on DUID; cases of drivers who were suspected to be under the influence of ethanol only were not considered. The final study population included 4794 DUID offenders (4243 males, 543 females). The mean age of all drivers was 31+/-12 years (range 14-92 years). One or more psychoactive drugs were detected in 89% of all analyzed blood samples. In 11% (N=530) of the samples, neither alcohol nor drugs were present. The most frequently encountered drugs in whole blood were cannabinoids (48% of total number of cases), ethanol (35%), cocaine (25%), opiates (10%), amphetamines (7%), benzodiazepines (6%) and methadone (5%). Other medicinal drugs such as antidepressants and benzodiazepine-like were detected less frequently. Poly-drug use was prevalent but it may be underestimated because the laboratories do not always analyze all drugs in a blood sample. This first Swiss study points out that DUID is a serious problem on the roads in Switzerland. Further investigations will show if this situation has changed in the following years.

Testing for cannabis in the work-place: a review of the evidence

BACKGROUND

Urinalysis testing in the work-place has been adopted widely by employers in the United States to deter employee drug use and promote 'drug-free' work-places. In other countries, such as Canada, testing is focused more narrowly on identifying employees whose drug use puts the safety of others at risk.

AIMS

We review 20 years of published literature on questions relevant to the objectives of work-place drug testing (WPDT), with a special emphasis on cannabis, the most commonly detected drug.

RESULTS

We conclude (i) that the acute effects of smoking cannabis impair performance for a period of about 4 hours; (ii) long-term heavy use of cannabis can impair cognitive ability, but it is not clear that heavy cannabis users represent a meaningful job safety risk unless using before work or on the job; (iii) urine tests have poor validity and low sensitivity to detect employees who represent a safety risk; (iv) drug testing is related to reductions in the prevalence of cannabis positive tests among employees, but this might not translate into fewer cannabis users; and (v) urinalysis has not been shown to have a meaningful impact on job injury/accident rates.

CONCLUSIONS

Urinalysis testing is not recommended as a diagnostic tool to identify employees who represent a job safety risk from cannabis use. Blood testing for active tetrahydrocannabinol (THC) can be considered by employers who wish to identify employees whose performance may be impaired by their cannabis use.

Can we cut the incidence of necrotizing enterocolitis in half--today?

Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency of neonates. Population studies estimate the incidence of NEC at between 0.3 and 2.4 per 1000 live births in the United States, with a predominance of cases among preterm neonates born at the earliest gestational ages. The disease burden of NEC includes an overall disease-specific mortality rate of 15-20%, with yet higher rates in those of earliest gestations. The NEC burden also includes an increase in hospital costs approximating $100,000/case, as well as severe late sequellae including parenteral nutrition-associated liver disease and short bowel syndrome. Differentiating NEC from other forms of acquired neonatal intestinal disease is critical to assessing the success of NEC prevention strategies. Promising new prevention strategies are now being tested; one such is prophylactic heparin-binding epidermal growth factor-like growth factor (HB-EGF) administration. However, two prevention strategies have already been shown in meta-analyses to reduce the incidence of NEC, but we speculate that these are not being fully utilized. They are; 1) implementing a written set of feeding guidelines (also called standardized feeding regimens) for newborn intensive care unit (NICU) patients, and 2) implementing programs to increase the availability of human milk for patients at risk of developing NEC.

The association between opioid analgesics and unsafe driving actions preceding fatal crashes

Currently, most epidemiological research into the impact of opioid analgesics on road safety has focused on the association between opioid use and traffic crash occurrence. Yet, the role of opioid analgesics on crash responsibility is still not properly understood. Therefore, we examined the impact of opioid analgesics on drivers (all had a confirmed BAC=0) involved in fatal crashes (1993-2006) using a case-control design based on data from the Fatality Analysis Reporting System. Cases had one or more crash-related unsafe driving actions (UDA) recorded; controls had none. We calculated adjusted odds ratios (ORs) of any UDA by medication exposure after controlling for age, sex, other medications, and driving record. Compared to drivers who tested negative for opioid analgesics, female drivers who tested positive demonstrated increased odds of performing an UDA from ages 25 (OR: 1.35; 95% CI: 1.05; 1.74) to 55 (OR: 1.30; 95% CI: 1.07; 1.58). For male drivers this was true from ages 25 (OR: 1.66; 95% CI: 1.32; 2.09) to 65 (OR: 1.39; 95% CI: 1.17; 1.67). The detection of opioid analgesics was not associated with greater risk of an UDA for older drivers. Research is necessary to examine why these age differences exist, and if possible, to ensure that opioid analgesics do not contribute to crashes.

The effects of drink-driving checkpoints on crashes--a meta-analysis

A meta-analysis has been conducted on the effects on crashes of DUI-checkpoints (DUI, driving under the influence). The results indicate that crashes involving alcohol are reduced by 17% at a minimum and that all crashes, independent of alcohol involvement, are reduced by about 10-15%. In a moderator analysis the effects of a number of factors that may affect the effectiveness of DUI-checkpoints were investigated by means of subgroup analyses and meta-regression. Those moderator variables that were found to be most relevant, are the time period studied, country, and study design. DUI-checkpoints were found to be most effective during the first half year. Australian checkpoints were found to be more effective than checkpoints in other countries. Smaller crash reductions were found in studies that have applied a control group than in other studies. Testing all drivers who are stopped at a checkpoint may improve the effectiveness of DUI-checkpoints. The results do not indicate that DUI-checkpoints have greater effects on more severe crashes or that the use of paid publicity improves the effectiveness. Most likely there are further factors that affect the effectiveness of DUI-checkpoints that could not be investigated in the present analysis.

Screening for drugs in oral fluid: drug driving and illicit drug use in a sample of Queensland motorists

OBJECTIVE

Random roadside oral fluid testing is becoming increasingly popular as an apprehension and deterrence-based countermeasure to reduce drug driving. This article outlines research conducted to provide an estimate of the extent of drug driving in a sample of drivers in Brisbane, Queensland.

METHODS

Oral fluid samples were collected from 1587 drivers who volunteered to participate at random breath testing (RBT) sites. Illicit substances tested for included cannabis (delta 9 tetrahydrocannibinol [THC]), meth/amphetamines, and cocaine. Drivers also completed a self-report questionnaire regarding their drug-related driving behaviors.

RESULTS

Oral fluid samples from 58 participants (3.7%) were confirmed positive for at least one illicit substance. The most common drugs detected in oral fluid were ecstasy (n = 35) followed by cannabis (n = 20). Similarly, cannabis was confirmed as the most common self-reported drug combined with driving. Nevertheless, individuals who tested positive to any drug through oral fluid analysis were also more likely to report the highest frequency of drug driving.

CONCLUSIONS

This research provides evidence that drug driving is relatively prevalent on some Queensland roads, and thus the behavior presents as a serious road safety threat. This article will further outline the study findings and present possible directions for future drug driving research.

Screening for drugs in oral fluid: illicit drug use and drug driving in a sample of Queensland motorists

Police Services in a number of Australian states have indicated random roadside drug testing will be implemented to target drug driving. This paper outlines research conducted to provide an estimate of the prevalence of drug driving in a sample of Queensland drivers. Oral fluid samples were collected from 781 drivers who volunteered to participate at Random Breath Testing (RBT) sites in a large Queensland regional area. Illicit substances tested for included cannabis (delta 9 tetrahydrocannibinol [THC]), amphetamine type substances, heroin and cocaine. Drivers also completed a self-report questionnaire regarding their drug-related driving behaviour. Samples that were drug-positive at initial screening were sent to a government laboratory for confirmation. Oral fluid samples from 27 participants (3.5%) were confirmed positive for at least one illicit substance. The most common drugs detected in oral fluid were cannabis (delta 9 THC) (n = 13) followed by amphetamine type substances (n = 11). A key finding was that cannabis was also confirmed as the most common self-reported drug combined with driving and that individuals who tested positive to any drug through oral fluid analysis were also more likely to report the highest frequency of drug driving. Furthermore, a comparison between drug vs drink driving detection rates for the study period revealed a higher detection rate for drug driving (3.5%) vs drink driving (0.8%). This research provides evidence that drug driving is relatively prevalent on Queensland Roads. The paper will further outline the study findings and present possible directions for future drug driving research.

Heavy vehicle driver fatalities: learning's from fatal road crash investigations in Victoria

This study describes the nature and extent of fatal heavy vehicle driver crashes in Victoria between 1999 and 2007 and the factors associated with the crash. A descriptive study was conducted comprising the population of heavy vehicle drivers killed in a road transport crash while operating a vehicle of > or =4.5 tonne Gross Vehicle Mass (GVM) for the purposes of work. Information about the nature of crash, environmental, driver, vehicle and occupational factors were collected from the coroner's death investigation file. Of the 91 deaths identified 61 were eligible for review. All 61 cases were male, solo drivers with a mean age of 44.7 years. Most vehicles were articulated in configuration. One-third of crash scenarios involved a single vehicle leaving the roadway on a straight road. One in every six fatally injured drivers was detected with the presence of stimulants or cannabis. Twenty-two drivers were travelling at excessive or inappropriate speeds for the circumstances. Seatbelt wearing status was documented for only 25 of 61 drivers. This study is the first to comprehensively examine a population of fatally injured heavy vehicle drivers using coroner's investigation files and these findings are consistent with previous, less detailed, Australian research. Information about potential associations between occupational factors and crash risk was limited. Improving driver safety requires incorporation of occupational factors into a standardised approach to heavy vehicle crash investigations.

A systematic review of research examining benzodiazepine-related mortality

PURPOSE

This paper will review literature examining the association of benzodiazepine use and mortality.

METHODS

An extensive literature review was undertaken to locate all English-language published articles that examine mortality risk associated with use of benzodiazepines from 1990 onwards.

RESULTS

Six cohort studies meeting the criteria above were identified. The results were mixed. Three of the studies assessed elderly populations and did not find an increased risk of death associated with benzodiazepine use, whereas another study of the general population did find an increased risk, particularly for older age groups. A study of a middle aged population found that regular benzodiazepine use was associated with an increased mortality risk, and a study of 'drug misusers' found a significant relationship between regular use of non-prescribed benzodiazepines and fatal overdose. Three retrospective population-based registry studies were also identified. The first unveiled a high relative risk (RR) of death due to benzodiazepine poisoning versus other outcomes in patients 60 or older when compared to those under 60. A positive but non-significant association between benzodiazepine use and driver-responsible fatalities in on-road motor vehicle accidents was reported. Drug poisoning deaths in England showed benzodiazepines caused 3.8% of all deaths caused by poisoning from a single drug.

CONCLUSION

On the basis of existing research there is limited data examining independent effects of illicit benzodiazepine use upon mortality. Future research is needed to carefully examine risks of use in accordance with doctors' prescriptions and extra-medical use.

Pathoanatomy of the lower cervical spine facet joints in motor vehicle crash fatalities

Non-lethal injuries to the cervical spine facet joints have previously been described in decedents from motor vehicle crashes and in clinical settings these joints have been identified as potential culprits in chronic neck pain syndromes. The aim of this study was to conduct a detailed examination of the lower cervical spine facet joints in a forensic cohort of motor vehicle crash victims and controls using comparable data from medicolegal autopsy, stereomicroscopy and histological evaluations. Injuries to the cervical spine facet joints were common in the trauma cases and included facet fractures, haemarthrosis, and disruption and bleeding in the synovial folds. The injuries could not be reliably verified on stereomicroscopic evaluation, and routine autopsy procedures did not reveal any of the injuries to the facet joints. Despite the presence of these pathoanatomical lesions in road traffic crash fatalities their prevalence and potential clinical implications in survivors from motor vehicle crashes is unknown.

Trends in driving under the influence of drugs: a register-based study of DUID suspects during 1977-2007

Our aim was to describe the incidence and trends of driving under the influence of drugs (DUID) and to examine the main drug findings and their trends in suspected DUID cases in Finland. A register-based study was conducted of all suspected DUID cases during 1977-2007. The data included 31,963 DUID offenders apprehended by the police with a positive finding for illicit/licit drug impairing driving performance. Toxicological results were analyzed in blood and/or urine specimens in one central laboratory. The incidence of suspected DUID cases increased 18-fold during 1977-2007. Most of the suspects were men (89.7%). However, the male-female ratio decreased from 13.9 to 7.3. The mean age decreased from 36.2 years in 1977 to 29.9 years in 2001 but has since reincreased. Most often found substances were benzodiazepines (75.7%), amphetamines (46.0%), cannabinoids (27.7%) and opioids (13.8%). Most common illicit drugs, amphetamines and cannabinoids, started to appear at the end of the 1980s. Poly-drug findings were common (77.1%). Suspected DUID cases have increased sharply after the introduction of a zero tolerance law, especially in regard to amphetamines. DUID is an increasing problem in Finland, and needs serious attention.

The impact of benzodiazepines on safe driving

OBJECTIVE

Benzodiazepines are prescribed to relieve anxiety and aid sleep. Studies demonstrate that benzodiazepines increase odds of crash involvement, but little evidence exists regarding their impact on crash responsibility. We examined the impact of benzodiazepines on crash responsibility by drug half-life and driver age, using a case-control design with drivers aged 20 and over involved in fatal crashes in the United States from 1993-2006.

METHODS

Drivers (all with BAC = 0) were classified as having no benzodiazepines detected versus short, intermediate, or long half-life benzodiazepines. Cases were drivers with at least one potentially unsafe driving action (UDA) in relation to the crash (e.g., speeding), a proxy measure for crash responsibility; controls had no UDAs recorded. Odds ratios (ORs) of any UDA by benzodiazepines half-life exposure were calculated, with adjustment for age, sex, other medication usage, and prior driving record.

RESULTS

Compared with drivers not using benzodiazepines, drivers taking intermediate or long half-life benzodiazepines demonstrated increased odds of an UDA from ages 25 (intermediate OR: 1.59; 95% CI = 1.08, 2.33; long OR: 1.68; 95% CI = 1.34, 2.12) to 55 (intermediate OR: 1.50; 95% CI = 1.09, 2.06; long OR: 1.33; 95% CI = 1.12, 1.57). Drivers taking short half-life benzodiazepines did not demonstrate increased odds compared to drivers not using benzodiazepines.

CONCLUSIONS

Given the potential impact of benzodiazepines on driver safety, further experimental research is needed to better understand the effect of benzodiazepines on crash responsibility.

Guidelines for research on drugged driving

AIMS

A major problem in assessing the true public health impact of drug-use on driving and overall traffic safety is that the variables being measured across studies vary significantly. In studies reported in a growing global literature, basic parameters assessed, analytical techniques and drugs tested are simply not comparable due to lack of standardization in the field. These shortcomings severely limit the value of this research to add knowledge to the field. A set of standards to harmonize research findings is sorely needed. This project was initiated by several international organizations to develop guidelines for research on drugged driving.

METHODS

A September 2006 meeting of international experts discussed the harmonization of protocols for future research on drugged driving. The principal objective of the meeting was to develop a consensus report setting guidelines, standards, core data variables and other controls that would form the basis for future international research. A modified Delphi method was utilized to develop draft guidelines. Subsequently, these draft guidelines were posted on the internet for global review, and comments received were integrated into the final document.

RESULTS

The Guidelines Document is divided into three major sections, each focusing upon different aspects of drugged driving research (e.g. roadside surveys, prevalence studies, hospital studies, fatality and crash investigations, etc.) within the critical issue areas of 'behavior', 'epidemiology' and 'toxicology'. The behavioral section contains 32 specific recommendations; (2) epidemiology 40 recommendations; and (3) toxicology 64 recommendations.

CONCLUSIONS

It is anticipated that these guidelines will improve significantly the overall quality of drugged driving research and facilitate future cross-study comparisons nationally and globally.

Limits of the quasi-induced exposure method when compared with the standard case-control design. Application to the estimation of risks associated with driving under the influence of cannabis or alcohol

The disparities between the quasi-induced exposure (QIE) method and a standard case-control approach with crash responsibility as disease of interest are studied. The 10,748 drivers who had been given compulsory cannabis and alcohol tests subsequent to involvement in a fatal crash in France between 2001 and 2003 were used to compare the two approaches. Odds ratios were assessed using conditional and unconditional logistic regressions. While both approaches found that drivers under the influence of alcohol or cannabis increased the risk of causing a fatal crash, the two approaches are not equivalent. They differ mainly with regards to the driver sample selected. The QIE method results in splitting the overall road safety issue into two sub-studies: a matched case-control study dealing with two-vehicle crashes and a case-control study dealing with single-vehicle crashes but with a specific control group. Using a specific generic term such as "QIE method" should not hide the real underlying epidemiological design. On the contrary, the standard case-control approach studies drivers involved in all type of crashes whatever the distribution of the responsibility in each crash. This method also known as "responsibility analysis" is the most relevant for assessing the overall road safety implications of a driver characteristic.

SAM survey on "drugs and fatal accidents": search of substances consumed and comparison between drivers involved under the influence of alcohol or cannabis

OBJECTIVES

A survey was conducted to produce reliable epidemiological data concerning the role played by alcohol and drugs in fatal road accidents in France. The aims are to describe the conduct of the survey, evaluate the overall quality of the findings, and analyze the substances consumed by the involved drivers. A comparison between drivers involved under the influence of alcohol only, cannabis only, or both substances is emphasized.

METHODS

By a June 1999 law, all drivers in France involved in an immediate fatality accident between October 2001 and 2003 had to undergo a urine test and, if that was not possible or the test proved positive, had a blood sample taken in order to test for drugs (cannabis, cocaine, heroin, amphetamines). The results were combined with the usual procedures of the police force, which include the results of tests for illegal alcohol levels. A unique and reliable set of accident data on the role of drugs was thus compiled for epidemiological purposes: 10,000 accident reports involving over 17,000 drivers were analyzed. The responsibility level of each driver involved in an accident was determined. Results were generated for a representative sample of about 11,000 drivers.

RESULTS

Alcohol levels above the legal limit (0.5 g/L of blood) were found in 21% of all drivers involved in accidents (killed, injured, or unharmed). Cannabis headed the list of illicit drugs detected, with a prevalence of 6.8% (THC > or = 1 ng/mL); it was present in the under-35s and especially the under-25s. About 40% of drivers under the influence of cannabis also had an illegal alcohol level. The other drugs, whether alone or in association with cannabis, are relatively rare. Accident characteristics of drivers detected positive for cannabis only are markedly different from drivers under the influence of alcohol. The overrepresentation of drivers responsible, from 1.7 over the whole population, rises to 2.3 for cannabis alone (THC > or = 1 ng/mL), to 9.4 for alcohol alone (> or =0.5 mg/L), and to 14.1 for the alcohol-cannabis combination.

CONCLUSIONS

The high incidence (26%) of alcohol or drugs among the population of drivers involved in fatal accidents highlights the importance for road safety of the consumption of these substances. Alcohol remains the major risk at any age. Young drivers consuming alcohol and cannabis represent a priority target for prevention.

Driving under the influence of cannabis: a 10-year study of age and gender differences in the concentrations of tetrahydrocannabinol in blood

BACKGROUND

Delta(9)-Tetrahydrocannabinol (THC) is the major psychoactive constituent of cannabis and its various preparations. Increasing use of cannabis for recreational purposes has created a problem for road-traffic safety. This paper compares age, gender and the concentrations of THC in blood of individuals apprehended for driving under the influence of drugs (DUID) in Sweden, where a zero-tolerance law operates.

MEASUREMENTS

Specimens of blood or urine were subjected to a broad screening analysis by enzyme immunoassay methods. THC positives were verified by analysis of blood by gas chromatography-mass spectrometry (GC-MS) with a deuterium-labelled internal standard (d(3)-THC). All toxicology results were entered into a database (TOXBASE) along with the age and gender of apprehended drivers.

FINDINGS

Over a 10-year period (1995-2004), between 18% and 30% of all DUID suspects had measurable amounts of THC in their blood (> 0.3 ng/ml) either alone or together with other drugs. The mean age [+/- standard deviation (SD)] of cannabis users was 33 +/- 9.4 years (range 15-66 years), with a strong predominance of men (94%, P < 0.001). The frequency distribution of THC concentrations (n = 8794) was skewed markedly to the right with mean, median and highest values of 2.1 ng/ml, 1.0 ng/ml and 67 ng/ml, respectively. The THC concentration was less than 1.0 ng/ml in 43% of cases and below 2.0 ng/ml in 61% of cases. The age of offenders was not correlated with the concentration of THC in blood (r = -0.027, P > 0.05). THC concentrations in blood were higher when this was the only psychoactive substance present (n = 1276); mean 3.6 ng/ml, median 2.0 ng/ml compared with multi-drug users; mean 1.8 ng/ml, median 1.0 ng/ml (P < 0.001). In cases with THC as the only drug present the concentration was less than 1.0 ng/ml in 26% and below 2.0 ng/ml in 41% of cases. The high prevalence of men, the average age and the concentrations of THC in blood were similar in users of illicit drugs (non-traffic cases).

CONCLUSIONS

The concentration of THC in blood at the time of driving is probably a great deal higher than at the time of sampling (30-90 minutes later). The notion of enacting science-based concentration limits of THC in blood (e.g. 3-5 ng/ml), as discussed in some quarters, would result in many individuals evading prosecution. Zero-tolerance or limit of quantitation laws are a much more pragmatic way to enforce DUID legislation.

Effect of chronic ethanol exposure on the hepatotoxicity of ecstasy in mice: an ex vivo study

3,4-Methylenedioxymethamphetamine (MDMA) is frequently consumed at "rave" parties by polydrug users that usually take this drug in association with ethanol. In addition, many young people are repeatedly exposed to ethanol, which likely leads to tolerance phenomena. Both compounds are metabolized in the liver, with formation of hepatotoxic metabolites, which gives high relevance to the evaluation of their putative toxicological interaction. Therefore, the aim of this study was to evaluate the toxicity induced by 0.8 and 1.6 mM MDMA to freshly isolated hepatocytes obtained from ethanol-treated mice whose tap drinking water was replaced by a 5% ethanol solution for 1 week and, afterwards, by a 12% ethanol solution for 8 weeks (ethanol group) comparatively to non-treated animals (non-ethanol group). The hepatocytes were incubated under normothermic and hyperthermic conditions in order to simulate in vitro the hyperthermic response induced in vivo by MDMA, a condition that has been recognized as a life-threatening effect associated with MDMA exposure and implicated in its hepatotoxicity. Six mice treated under the same protocol as the ethanol group were used for histological analysis, and compared to non-ethanol-treated animals. The pre-treatment of mice with ethanol caused a significant decrease in the hepatocytes yield in the isolation procedure comparatively to the non-ethanol group, which can be explained by an increase in collagen deposition along the hepatic parenchyma as observed in the histological analysis. The initial cell viability of hepatocytes suspensions was similar between ethanol and non-ethanol groups. However, the ethanol group showed a higher GSH oxidation rate, which was enhanced under hyperthermia. Additionally, a concentration-dependent MDMA-induced loss of cell viability and ATP depletion was observed for both groups, at 41 degrees C. In conclusion, the repeated treatment with ethanol seems to increase the vulnerability of freshly isolated mice hepatocytes towards pro-oxidant conditions, as ascertained by the increase in collagen deposition, lower hepatocyte yield and decreased glutathione levels. However, MDMA toxicity to the isolated hepatocytes was independent of ethanol pre-treatment, while significantly dependent on incubation temperature.

Driving behavior under the influence of cannabis or cocaine

OBJECTIVE

The purpose of this study is first to describe perceptions of driving under the influence of cannabis or cocaine among clients in treatment and, second, to assess whether these perceptions are related to the frequency of driving under the influence of cannabis or cocaine.

METHODS

A questionnaire was administered to clients in treatment for abuse of either cocaine or cannabis, many of whom also had a problem with alcohol; additional groups of clients consisted of those in smoking cessation and gambling programs (N = 1021). Open-ended and close-ended questions were used to assess self-reported effects of cannabis or cocaine on driving and frequency of driving under the influence of cannabis, cocaine, or alcohol.

RESULTS

Two dimensions of driving behavior under the influence of cocaine or cannabis were found in both qualitative and quantitative analyses: 1) physical effects and 2) reckless styles of driving. Common physical effects for both drugs were heightened nervousness, greater alertness, and poorer concentration. In terms of driving behavior, cautious or normal driving was commonly reported for cannabis, whereas reckless or reduced driving ability was frequently reported for cocaine. When comparing negative physical effects and reckless style of driving with frequency of driving under the influence of cannabis or cocaine, increased negative physical effects from cannabis were inversely related to frequency of driving under the influence of cannabis (p = .001), but other relationships were not significant.

CONCLUSIONS

The findings indicate that both cannabis and cocaine have detrimental but different effects on driving. The negative physical effects of cannabis may reduce the likelihood of driving under the influence of cannabis.

Prevalence of psychoactive substances in truck drivers in the Nord-Pas-de-Calais region (France)

A previous study conducted in 1995 showed that psychoactive drug use by workers was higher in safety/security workstations than in the rest of the labour force. In order to verify this finding, we conducted a new study in 2003-2004 in the Nord-Pas-de-Calais region, restricted to truck drivers. The aim of this study was to allow harmonizing the professional practice of the occupational physicians, proposing drug prevention and drug testing policies, validating the analytical methods and the guidelines in case of positive testing results. One thousand truck drivers were studied. Urines were tested for amphetamines, cannabinoids, cocaine, opiates, benzodiazepines, buprenorphine and methadone by immunoassay. Urine ethanol determinations were performed by an ADH method. Positive urines for drugs of abuse, methadone or buprenorphine were then tested by gas chromatography or liquid chromatography coupled to mass spectrometry. Out of the 1000 drivers, cannabinoids were detected in 85 cases, opiates in 41 cases, amphetamines in 3 cases and cocaine in only one case. Buprenorphine was detected in 18 cases, methadone in 5 cases and benzodiazepines in 4 cases. Urine ethanol was positive in 50 cases. We found only one case with 6-monoacetylmorphine. Other positive opiates were metabolites of antitussives. The relatively low number of benzodiazepine positive urines could be explained by the lack of sensitivity of the test we used. All these results confirm those of the previous study for cannabinoids and ethanol in safety/security workstations. Positive results for methadone and buprenorphine are eight times higher than in the general population. In conclusion, the authors think that it will be of a great interest to test urine of truck drivers for other classes of psychoactive drugs, using a liquid chromatography-mass spectrometry method.

Drug use in motor vehicle drivers presenting to an Australian, adult major trauma centre

OBJECTIVES

To determine the drug use in injured Victorian drivers involved in motor vehicle collisions and subsequently transported to a major adult trauma centre in Victoria.

METHODS

A blood sample was obtained from patients who had been taken to The Alfred Emergency & Trauma Centre (Prahran, Vic., Australia) following a motor vehicle collision. This was performed at the same time and under the same law as compulsory blood screening in Victoria (Section 56 of the Road Safety Act). Four hundred and thirty-six specimens were analysed. Blood stored in vacutainer tubes containing preservative were screened for drugs using enzyme-linked immunosorbent assay and gas chromatography-mass spectometry analysis. Medically administered drugs were excluded from the results.

RESULTS

Four hundred and thirty-six specimens were analysed. Metabolites of cannabis were the most commonly found drug (46.7%), the active form of cannabis (Delta9-tetrahydrocannabinol) was found in 33 specimens (7.6%). The next most prevalent drugs were benzodiazepines (15.6%), opiates (11%), amphetamines (4.1%) and methadone (3%). Cocaine was detected in 1.4% of cases. Of the motor vehicle collisions 66% involved males and females of 15-44 years old and Delta9-tetrahydrocannabinol was almost exclusively found in this age group. In motor vehicle collisions involving older drivers there was an increasing use of benzodiazepines. In women >65 years old 30% were positive for benzodiazepines.

CONCLUSIONS

Drug usage found in this group of injured drivers was disturbingly high. The introduction of further initiatives to decrease the prevalence of drug use in motor vehicle drivers is required.

Drugs in oral fluid in randomly selected drivers

There were 13,176 roadside drug tests performed in the first year of the random drug-testing program conducted in the state of Victoria. Drugs targeted in the testing were methamphetamines and Delta(9)-tetrahydrocannabinol (THC). On-site screening was conducted by the police using DrugWipe, while the driver was still in the vehicle and if positive, a second test on collected oral fluid, using the Rapiscan, was performed in a specially outfitted "drug bus" located adjacent to the testing area. Oral fluid on presumptive positive cases was sent to the laboratory for confirmation with limits of quantification of 5, 5, and 2 ng/mL for methamphetamine (MA), methylenedioxy-methamphetamine (MDMA), and THC, respectively. Recovery experiments conducted in the laboratory showed quantitative recovery of analytes from the collector. When oral fluid could not be collected, blood was taken from the driver and sent to the laboratory for confirmation. These roadside tests gave 313 positive cases following GC-MS confirmation. These comprised 269, 118, and 87 cases positive to MA, MDMA, and THC, respectively. The median oral concentrations (undiluted) of MA, MDMA, and THC was 1136, 2724, and 81 ng/mL. The overall drug positive rate was 2.4% of the screened population. This rate was highest in drivers of cars (2.8%). The average age of drivers detected with a positive drug reading was 28 years. Large vehicle (trucks over 4.5 t) drivers were older; on average at 38 years. Females accounted for 19% of all positives, although none of the positive truck drivers were female. There was one false positive to cannabis when the results of both on-site devices were considered and four to methamphetamines.

Prevalence of alcohol and illicit drugs in blood specimens from drivers involved in traffic law offenses. Systematic review of cross-sectional studies

OBJECTIVE

To determine which is the reported prevalence of alcohol and illicit drugs in blood specimens from drivers involved in traffic law offenses worldwide.

METHODS

The search was performed by using several international biomedical databases. In order to reduce publication bias, additional publications were identified using further sources of information. The present review includes cross-sectional studies published between 1990 and 2005 in English, Spanish, German, Portuguese, and Italian. Only studies based on the analysis of blood specimens and chromatographic quantification of drugs were included.

RESULTS

Forty-nine studies fulfilled the inclusion criteria. Eighteen were excluded considering practical reasons regarding limitations for a reliable interpretation of their results. Alcohol appears to be still the predominant substance, with the consideration that among drivers primarily suspected of DUID, cannabinoids are more prevalent. Among the illicit drugs, cannabinoids are the most commonly found substance. Certain trends could be identified, e.g., very low prevalence of cocaine in reports from Nordic countries, a high prevalence of amphetamines between Norwegian and Swedish studies, and low rates of THC among Australian studies.

CONCLUSION

The results of this study should be regarded as an attempt to obtain more reliable data concerning the prevalence of alcohol and illicit drugs among drivers. To obtain a better assessment of the real current role of alcohol and drugs (illicit and medications), it seems strongly necessary to update the case-control study conducted by Borkenstein et al. in 1964, including now blood analyses of the whole spectrum of substances that can impair drivers.

Sonolência diurna excessiva em pré-vestibulandos

OBJETIVO: O sono é um fenômeno que interfere nos aspectos cognitivos. O objetivo deste estudo foi avaliar a prevalência da sonolência diurna excessiva (SDE) em pré-vestibulandos de Campo Grande, MS. MÉTODOS: Foram entrevistados 378 alunos com a escala de sonolência Epworth (ESE). As variáveis foram: sexo, uso esporádico de bebidas alcoólicas e fumo, relato de sinais e sintomas depressivos, renda familiar total dos membros do lar e idade. Foram empregados os testes qui-quadrado e de análise de variância. RESULTADOS: Em relação ao gênero, 50,3% eram homens e 49,7% mulheres; 39,2% ingeriam álcool; 6,6% fumavam e 33% já tinham tido depressão na vida. Entre os alunos, 55,8% tinham SDE, 5,3% eram indicativos de ter distúrbio respiratório ou síndrome da apnéia do sono. Foram detectadas associações entre as variáveis consumo de álcool e tabagismo, em relação à ESE. CONCLUSÕES: Foi alta a prevalência de SDE, sendo detectadas associações entre as variáveis uso esporádico de álcool e fumo, em relação à ESE. Novos estudos devem ser realizados a fim de prevenir as alterações cognitivas entre os pré-vestibulandos que apresentam SDE ou outro distúrbio do sono.

Roadside detection of impairment under the influence of ketamine--evaluation of ketamine impairment symptoms with reference to its concentration in oral fluid and urine

Although there are many roadside testing devices available for the screening of abused drugs, none of them can be used for the detection of ketamine, a popular abused drug in Hong Kong. In connection to local drug driving legislation, effective roadside detection of ketamine in suspected drug-impaired drivers has to be established. According to the drug evaluation and classification program (DEC), ketamine is classified in the phencyclidine (PCP) category. However, no study has been performed regarding the signs and symptoms exhibited by users under the influence of ketamine. In a study to develop a protocol for effective roadside detection of drug-impaired drivers, 62 volunteers exiting from discos were assessed using field impairment tests (FIT) that included measurements of three vital signs (i.e. body temperature, pulse rate and blood pressure), three eye examinations [pupil size, lack of convergence (LOC) and horizontal gaze nystagmus (HGN)] and four divided attention tests (Romberg, one-leg stand, finger-to-nose and walk-and-turn tests). Subsequent laboratory analysis of oral fluid and urine samples from the participants revealed the presence of common abused drugs in both the urine and oral fluid samples of 55 subjects. The remaining 7 subjects with no drug in their oral fluid samples were used as drug-free subjects. In addition, 10 volunteers from the laboratory who were regarded as drug-free subjects were also assessed using the same FIT. Among the 62 volunteers, 39 of them were detected with ketamine in their oral fluid. Of these ketamine users, 21 of them (54%) with only ketamine found in their oral fluid samples while the rest (18 subjects) of them had other drugs (i.e. MA, MDMA, benzodiazepines and/or THC) in addition to ketamine. Of the 21 ketamine-only users, 15 of them (71%) were successfully identified by FIT. It was found that when salivary ketamine concentrations were greater than 300 ng/mL, signs of impairment became evident, with over 90% detection rate using the FIT. By comparing the FIT observations on the 21 ketamine-only users with the drug-free subjects, the typical signs and symptoms observable for subjects under the influence of ketamine included LOC, HGN, elevated pulse rate and in general, failing the divided attention tests, especially the walk-and-turn and one-leg stand.

The acute effects of d-amphetamine and methamphetamine on attention and psychomotor performance

RATIONALE

It is not clear how the deleterious effects of amphetamines on driving performance are mediated in terms of select cognitive processes.

OBJECTIVES

The current three separate experiments assessed the acute effects of an oral dose of either 0.42-mg/kg d-amphetamine, d,l-methamphetamine and d-methamphetamine on driving-related cognitive functions in a total of 60 healthy non-fatigued adults.

MATERIALS AND METHODS

Three separate repeated measures counterbalanced, double-blind, placebo-controlled designs were employed in which 20 volunteers completed two treatment conditions, either d-amphetamine, d,l-methamphetamine or d-methamphetamine and placebo. Performance was assessed on a range of attentional, psychomotor and perceptual speed tasks.

RESULTS

Mean blood concentrations at 120-, 170- and 240-min postdrug administration were 83, 98 and 96 ng/ml, respectively, for d-amphetamine, 90, 95 and 105 ng/ml, respectively, for d,l-methamphetamine and 72, 67 and 59 ng/ml, respectively, for d-methamphetamine. The amphetamines, in general, improved various aspects of attention (Digit Vigilance, Digit Symbol Substitution Test and Movement Estimation Performance) with some evidence to suggest possible enhancement in psychomotor functioning (Tracking ability) and perceptual speed (Inspection Time).

CONCLUSIONS

The current series of studies primarily provides evidence of low-level amphetamine-related enhancement of function; however, it also provides evidence of less conservative movement estimation that might contribute to amphetamine-related road fatalities.

Relationship between THC concentration in blood and impairment in apprehended drivers

OBJECTIVE

The most important psychoactive ingredient in cannabis, Delta (9)-tetrahydrocannabinol (THC) is one of the most frequently detected substances in blood samples from suspected impaired drivers in Norway. There is growing concern over possible links between the use of cannabis and increased risk of motor-vehicle crashes. Experimental studies have provided useful information on the role of THC and dose-effect relations with respect to psychomotor performance. The main purpose of the present study was to investigate whether a physician's judgment on impairment in a real-life setting among suspected drugged drivers, was related to blood THC concentration.

METHODS

In Norway a police physician performs a clinical test for impairment (CTI) shortly after apprehension. The Norwegian Institute of Public Health analyze blood samples from all drivers suspected of driving under the influence of non-alcoholic drugs. In the present study 589 samples from approximately 30,000 cases of suspected drug impaired driving from the period 1997-99, contained THC as the only drug. In 456 of these cases a conclusion of the CTI was available.

RESULTS

230 (54%) drivers were considered not impaired and 226 (46%) impaired. Impaired drivers had higher blood THC concentration than the drivers who were judged as not impaired (median; 2.5 ng/mL (range; 0.3-45.3 ng/mL) vs 1.9 ng/mL (range; 0.32-24.8 ng/mL), (p < 0.05). Furthermore, drivers with blood THC concentrations above 3 ng/mL had an increased risk for being judged impaired compared to drivers with lower concentration ranges.

CONCLUSION

The relationship between the concentration of THC in blood and risk of being assessed impaired found in this cross-sectional study of suspected drugged drivers, supports findings from previous experimental studies of concentration related effects of THC on psychomotor performance and driving skills.

Sideswipe injuries to the elbow in Western Australia

OBJECTIVE

To examine the conditions leading to sideswipe injury of the upper limb in motor vehicle accidents and to highlight the severity of these injuries.

DESIGN AND SETTING

Prospective study of upper-limb sideswipe injuries in patients admitted to Royal Perth Hospital, Western Australia, between August 2003 and January 2005.

PARTICIPANTS

Eleven patients sustaining sideswipe injuries to the upper limb.

MAIN OUTCOME MEASURES

Accident pattern, type of injury, surgical management, complications, and functional and employment implications.

RESULTS

Ten patients required open reduction and internal fixation for open fractures of the humerus, ulna and radius, and nine underwent additional surgical procedures including nerve, artery and tendon repair, and free flaps and split-skin grafting. The injury severity scores ranged from 9 to 25. The severity of injuries led to extensive functional deficits in eight patients, affecting employment prospects in seven.

CONCLUSION

Appropriate educational programs, legislation and improvements in traffic conditions, especially in rural areas, as well as changes in current car design, could contribute to preventing these devastating and complex injuries.

Injury associated with methamphetamine use: a review of the literature

This paper reviews the literature exploring issues around methamphetamine and injury. There was a paucity of peer reviewed quantitative research and a lack of large scale epidemiological studies. Further sources described cases and others described injury risk as part of an overall review of methamphetamine misuse. Thus, a number of limitations and potential biases exist within the literature. The main areas where associations were noted or extrapolated with methamphetamine use and injury were around driving and violence. Other associations with injury related to methamphetamine manufacture. There was also circumstantial evidence for third party injury (that is injury to those not specifically involved in drug use or drug manufacture); however, the available data are inadequate to confirm these associations/risks.

Relapse to driving under the influence (DUI): A review

Driving under the influence (DUI) is a major public health problem. In 2003, there were 17,401 alcohol-related crash fatalities. Although there has been a large decrease in the fatality rates over the past two decades, further progress has stalled in recent years. This plateau in the injury and death rates resulting from impaired driving has been attributed, in part, to the persistent or repeat DUI offender. Broadly defined, repeat offenders are those individuals who, following an initial DUI arrest, relapse to driving under the influence of alcohol and other drugs. In this paper, we first provide a brief overview of several models of DUI relapse. We then review the empirical literature on DUI relapse, the data describing characteristics of first-time and repeat DUI offenders, and, especially, studies that have evaluated the impact of legal sanctions and rehabilitation programs on subsequent DUI behavior. The data reveal that DUI offenders are a heterogeneous group, and that simple models relying on only one or two behavioral domains (e.g., driving characteristics, demographics) to explain DUI relapse are insufficient to account for the DUI behavior of offenders. To advance our understanding of DUI relapse, we argue for development and testing of multifactorial models focusing on the interplay of legal, social and psychological factors that describe and explain relapse among DUI offenders. By recognizing the heterogeneity within the offender population it will be easier for researchers and clinicians to identify subgroups that are at high-risk for relapse and which should be targeted by prevention and intervention programs.

Cannabis intoxication and fatal road crashes in France: population based case-control study

OBJECTIVES

To evaluate the relative risk of being responsible for a fatal crash while driving under the influence of cannabis, the prevalence of such drivers within the driving population, and the corresponding share of fatal crashes.

DESIGN

Population based case-control study.

PARTICIPANTS

10 748 drivers, with known drug and alcohol concentrations, who were involved in fatal crashes in France from October 2001 to September 2003.

MAIN OUTCOME MEASURES

The cases were the 6766 drivers considered at fault in their crash; the controls were 3006 drivers selected from the 3982 other drivers. Positive detection of cannabis was defined as a blood concentration of Delta9tetrahydrocannabinol of over 1 ng/ml. The prevalence of positive drivers in the driving population was estimated by standardising controls on drivers not at fault who were involved in crashes resulting in slight injuries.

RESULTS

681 drivers were positive for cannabis (cases 8.8%, controls 2.8%), including 285 with an illegal blood alcohol concentration (> or = 0.5 g/l). Positive cannabis detection was associated with increased risk of responsibility (odds ratio 3.32, 95% confidence interval 2.63 to 4.18). A significant dose effect was identified; the odds ratio increased from 2.18 (1.22 to 3.89) if 0 < Delta9tetrahydrocannabinol < 1 ng/ml to 4.72 (3.04 to 7.33) if Delta9tetrahydrocannabinol > or = 5 ng/ml. The effect of cannabis remains significant after adjustment for different cofactors, including alcohol, with which no statistical interaction was observed. The prevalence of cannabis (2.9%) estimated for the driving population is similar to that for alcohol (2.7%). At least 2.5% (1.5% to 3.5%) of fatal crashes were estimated as being attributable to cannabis, compared with 28.6% for alcohol (26.8% to 30.5%).

CONCLUSIONS

Driving under the influence of cannabis increases the risk of involvement in a crash. However, in France its share in fatal crashes is significantly lower than that associated with positive blood alcohol concentration.

Drugs and chronic alcohol abuse in drivers

Blood specimens from 210 drivers (179 male and 31 female) apprehended in Luxembourg from autumn 2001 to spring 2002 and requested for the determination of their blood alcohol concentration (BAC) were tested for medicinal drugs, illicit drugs, and chronic alcohol abuse (by quantification of the carbohydrate-deficient transferrin: CDT). These additional analyses were performed anonymously and with permission of state prosecutor. The 22.8% had consumed medicinal drugs, with benzodiazepines and antidepressants (10.9 and 7.6%, respectively) as main psychoactive classes. Cannabis was the most detected illicit drug (9.5%) but only one in three had THC detectable in their blood. Association of two or more psychoactive substances (poly-drug use) was observed in 27.6% of drivers (90.6% of drug consumers). On the basis of CDT values, 29.5% of drivers investigated were assumed to be chronic alcohol abusers. Statistical analysis revealed that chronic alcohol abuse and medicinal psychoactive drugs were associated with significantly higher BAC. Medicinal psychoactive drugs were clearly associated with poly-drug use, and were furthermore detected at supra-therapeutic levels in 34.9%.

Sleep habits, sleepiness and accidents among truck drivers

OBJECTIVE: To evaluate the quality of sleep, shift work, alcohol and psychostimulant drug use, and the prevalence of accidents among truck drivers. METHOD: Data were collected using a demographic questionnaire, the Epworth Sleepiness Scale (ESS) and the Pittsburgh sleep quality index (PSQI). Statistical analysis was conducted using the Student t, chi-square, Pearson and Fisher tests. RESULTS: 43.2% of the drivers drove over 16 h a day, and 2.9% worked shifts. Mean number of sleep hours/day was 5.97±1.47; 23.8% slept <5 hours; 50.9% made use of alcohol, 95.6% of caffeine, and 11.1% of amphetamines. Mean PSQI was 4.95±2.56; 35.4% had a PSQI >5; 23 subjects snored more than three times a week (11.1%). Mean ESS was 6.56±4.2; 21.7% had a score >10. In the preceding five years, 27 drivers (13.1%) were involved in accidents, 5 of which resulted in injuries and 3 in deaths. CONCLUSION: Results showed a high prevalence of sleep disorders, use of alcohol and psychostimulant drugs, and accidents.

The relationship between performance on the standardised field sobriety tests, driving performance and the level of Δ9-tetrahydrocannabinol (THC) in blood

The consumption of Delta9-tetrahydrocannabinol (THC) as cannabis has been shown to result in impaired and culpable driving. Testing drivers for the presence of THC in blood is problematic as THC and its metabolites may remain in the blood for several days following its consumption, even though the drug may no longer have an influence on driving performance. In the present study, the aim was to assess whether performance on the standardised field sobriety tests (SFSTs) provides a sensitive measure of impaired driving behaviour following the consumption of THC. In a repeated measures design, 40 participants consumed cigarettes that contained either 0% THC (placebo), 1.74% THC (low dose) or 2.93% THC (high dose). For each condition, after smoking a cigarette, participants performed the SFSTs on three occasions (5, 55 and 105 min after the smoking procedure had been completed) as well as a simulated driving test on two occasions (30 and 80 min after the smoking procedure had been completed). The results revealed that driving performance was not significantly impaired 30 min after the consumption of THC but was significantly impaired 80 min after the consumption of THC in both the low and high dose conditions. The percentage of participants whose driving performance was correctly classified as either impaired or not impaired based on the SFSTs ranged between 65.8 and 76.3%, across the two THC conditions. The results suggest that performance on the SFSTs provides a moderate predictor of driving impairment following the consumption of THC and as such, the SFSTs may provide an appropriate screening tool for authorities that wish to assess the driving capabilities of individuals suspected of being under the influence of a drug other than alcohol.

An evaluation of the sensitivity of the standardised field sobriety tests to detect the presence of amphetamine

RATIONALE

The Standardised Field Sobriety Tests (SFSTs), designed and validated to assess impairment associated with alcohol intoxication, are currently being employed by the Victoria Police (Australia) for the identification of driving impairment associated with drugs other than alcohol.

OBJECTIVES

The aim of this study was to evaluate whether the SFSTs are a sensitive measure for identifying the presence of dexamphetamine and methamphetamine.

METHODS

Three studies each employed a repeated-measures, counterbalanced, double-blind placebo-controlled design. In each study, 20 healthy volunteers completed two treatment conditions: either 0.42 mg/kg d,l-dexamphetamine and placebo, 0.42 mg/kg d,l-methamphetamine and placebo, or 0.42 mg/kg d-methamphetamine and placebo. Performance was assessed using the SFSTs, consisting of the Horizontal Gaze Nystagmus test, the Walk and Turn test, and the One Leg Stand test. Blood and saliva samples were obtained before and immediately after the administration of the SFSTs (120 and 170 min post drug administration).

RESULTS

At 120 and 170 min post drug administration, d,l-dexamphetamine blood levels were 83.16 and 98.42 ng/ml, respectively; d,l-methamphetamine levels were 90 and 95 ng/ml, respectively; and d-methamphetamine blood levels were 72 and 67 ng/ml, respectively. None of the three amphetamine doses impaired performance on the SFSTs. Using the SFSTs, the presence of dexamphetamine was identified in 5% of cases, d-methamphetamine in 5%, and d,l-methamphetamine in 0% of cases.

CONCLUSIONS

Under these conditions, the SFSTs are not a sensitive measure for detecting the presence of low levels of amphetamine.

Alcohol and drugs in drivers fatally injured in traffic accidents in Sweden during the years 2000–2002

During the years 2000-2002, alcohol, pharmaceuticals and illicit drugs were analysed in blood samples from fatally injured drivers in Sweden. The total number of drivers was 920 and in 855 of these, corresponding to 93%, a toxicological investigation was performed. About 85% of the drivers were men and 15% were women. All but three women (96%) were car drivers while the corresponding figure for men was about 78% and about 13% were motorcyclists. The number of positive cases increased from 38.9% in year 2000 to 45.9% in year 2002 and alcohol was the most common drug with frequencies of 19.8%, 25.0% and 21.8% for the studied years 2000, 2001 and 2002, respectively. The median blood alcohol concentration ranged from 1.6 to 2.0mg/mL for men and from 1.2 to 1.8 mg/mL for women. There was a decrease in cases where alcohol was the only drug detected, from 52 out of 58 cases (90%) in year 2000 to 41 out of 61 cases (67%) in 2002. At the same time there was an increase, from 5.4% to 10.0% of illicit drugs, mainly amphetamine, and the cases with multiple drug intake increased from 10% to 26%. The prevalence of pharmaceuticals as the only drug or drugs detected decreased from 14.0% to 10.4% and in the majority of these cases the drug concentrations were within the therapeutic range.

An evaluation of the sensitivity of the Standardised Field Sobriety Tests (SFSTs) to detect impairment due to marijuana intoxication

The Standardised Field Sobriety Tests (SFST) were developed to test for alcohol intoxication but are currently being used by the State Police of Victoria (Australia) to test for driving impairment associated with drugs other than alcohol. The aim of the present study was to assess whether the SFSTs provide a sensitive measure of impairment following the consumption of a drug other than alcohol: delta-9-tetrahydrocannabinol (THC or cannabis). In a repeated-measures design, 40 participants consumed cigarettes that contained either 0% THC (placebo), 1.74% THC (low dose) or 2.93% THC (high dose). For each condition, after smoking a cigarette, participants performed the SFSTs on three occasions: 5 min (Time 1), 55 min (Time 2) and 105 min (Time 3) after the smoking procedure had been completed. The results revealed that there was a positive relationship between the dose of THC administered and the number of participants classified as impaired based on the SFSTs. Results also revealed that the percentage of participants classified as impaired decreased from Time 1 to Time 3 and that the addition of a new sign, head movements or jerks (HMJ), increased the percentage of participants classified as impaired in both the low and high THC conditions. These findings suggest that impaired performance on the SFSTs is positively related to the dose of THC administered and that the inclusion of HMJ as a scored sign in the SFSTs improves their predictive validity when testing for THC intoxication.