The effect of d-methamphetamine on simulated driving performance

OBJECTIVES

Methamphetamine is considered to be one of the most popularly abused drugs by drivers; however, its exact effect on driving and driving behaviour has yet to be thoroughly investigated. This being despite methamphetamine's increased prevalence in injured and deceased drivers.

METHODS

Twenty healthy recreational illicit stimulant users (10 male and 10 female), aged between 21 and 32 years (mean = 25.4 years, SD = 3.3 years) attended two testing sessions involving oral consumption of 0.42 mg/kg d-methamphetamine or a matching placebo. The drug administration was counter-balanced, double-blind, and medically supervised. At each session driving, performance was assessed 2.5 h post drug administration.

RESULTS

d-methamphetamine (0.42 mg/kg) did not significantly impair overall simulated driving performance 2.5 h post drug administration. At the individual driving variable level, participants in the d-methamphetamine condition were observed to be driving slower when an emergency situation occurred (T = 44, p < 0.05), but interestingly, participants in both conditions recorded average speeds in excess of the speed limit (100 km/h) when the emergency situations occurred. The d-methamphetamine condition did also produce four times more infringements where participants did not stop at red traffic light in comparison to the placebo, but this effect was only evident at a trend level (T = 7, p = 0.11).

CONCLUSIONS

The findings presented herein suggest that d-methamphetamine administered at the levels supplied did not impair driving performance in a manner consistent with epidemiological evidence. Further research is certainly required to elucidate the effects of various doses of methamphetamine, alone and in combination with other legal and illicit substances.

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.

The involvement of drugs in drivers of motor vehicles killed in Australian road traffic crashes

A multi-center case-control study was conducted on 3398 fatally-injured drivers to assess the effect of alcohol and drug use on the likelihood of them being culpable. Crashes investigated were from three Australian states (Victoria, New South Wales and Western Australia). The control group of drug- and alcohol-free drivers comprised 50.1% of the study population. A previously validated method of responsibility analysis was used to classify drivers as either culpable or non-culpable. Cases in which the driver "contributed" to the crash (n=188) were excluded. Logistic regression was used to examine the association of key attributes such as age, gender, type of crash and drug use on the likelihood of culpability. Drivers positive to psychotropic drugs were significantly more likely to be culpable than drug-free drivers. Drivers with Delta(9)-tetrahydrocannabinol (THC) in their blood had a significantly higher likelihood of being culpable than drug-free drivers (odds ratio (OR) 2.7, 95% CI 1.02-7.0). For drivers with blood THC concentrations of 5 ng/ml or higher the odds ratio was greater and more statistically significant (OR 6.6, 95% CI 1.5-28.0). The estimated odds ratio is greater than that for drivers with a blood alcohol concentration (BAC) of 0.10-0.15% (OR 3.7, 95% CI 1.5-9.1). A significantly stronger positive association with culpability was seen with drivers positive to THC and with BAC > or =0.05% compared with BAC > or =0.05 alone (OR 2.9, 95% CI 1.1-7.7). Strong associations were also seen for stimulants, particularly in truck drivers. There were non-significant, weakly positive associations of opiates and benzodiazepines with culpability. Drivers positive to any psychoactive drug were significantly more likely to be culpable (OR 1.8, 95% CI 1.3-2.4). Gender differences were not significant, but differences were apparent with age. Drivers showing the highest culpability rates were in the under 25 and over 65 age groups.

Dose related risk of motor vehicle crashes after cannabis use

The role of Delta(9)-tetrahydrocannabinol (THC) in driver impairment and motor vehicle crashes has traditionally been established in experimental and epidemiological studies. Experimental studies have repeatedly shown that THC impairs cognition, psychomotor function and actual driving performance in a dose related manner. The degree of performance impairment observed in experimental studies after doses up to 300 microg/kg THC were equivalent to the impairing effect of an alcohol dose producing a blood alcohol concentration (BAC) >/=0.05 g/dl, the legal limit for driving under the influence in most European countries. Higher doses of THC, i.e. >300 microg/kg THC have not been systematically studied but can be predicted to produce even larger impairment. Detrimental effects of THC were more prominent in certain driving tasks than others. Highly automated behaviors, such as road tracking control, were more affected by THC as compared to more complex driving tasks requiring conscious control. Epidemiological findings on the role of THC in vehicle crashes have sometimes contrasted findings from experimental research. Case-control studies generally confirmed experimental data, but culpability surveys showed little evidence that crashed drivers who only used cannabis are more likely to cause accidents than drug free drivers. However, most culpability surveys have established cannabis use among crashed drivers by determining the presence of an inactive metabolite of THC in blood or urine that can be detected for days after smoking and can only be taken as evidence for past use of cannabis. Surveys that established recent use of cannabis by directly measuring THC in blood showed that THC positives, particularly at higher doses, are about three to seven times more likely to be responsible for their crash as compared to drivers that had not used drugs or alcohol. Together these epidemiological data suggests that recent use of cannabis may increase crash risk, whereas past use of cannabis does not. Experimental and epidemiological research provided similar findings concerning the combined use of THC and alcohol in traffic. Combined use of THC and alcohol produced severe impairment of cognitive, psychomotor, and actual driving performance in experimental studies and sharply increased the crash risk in epidemiological analyses.

Injury risk associated with cannabis and cocaine use

The purpose of this paper is to review the results and limitations of studies of injury risks associated with cannabis and cocaine use. Three types of fatal and non-fatal injuries are considered: injuries due to collisions, intentional injuries and injuries in general. Four types of studies were reviewed: (I) laboratory studies, (II) descriptive and analytic epidemiological studies on the prevalence of cannabis or cocaine use through drug testing of those injured, (III) studies of non-clinical samples, and (IV) studies of clinical samples of drug users. The research that utilized drug tests showed similar proportions testing positive for cannabis in fatal and non-fatal injury groups, and for collisions, violence and injuries in general. By contrast, large differences in the average proportions testing positive for cocaine were found among these same injury groups. For example, 28.7% of people with intentional injuries (primarily homicides) tested positive for cocaine, while 4.5% of injured drivers tested positive. Studies of non-clinical samples have shown that both cannabis and cocaine use are related to intentional injuries and injuries in general. Results indicate higher risk for all types of injuries among cannabis and cocaine clients in treatment. Strengths and limitations of the different types of studies are discussed. More rigorous studies are needed which should focus on ruling out alternative explanations for relationships between drug use and injuries.

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

The incidence of alcohol and drugs in fatally injured drivers were determined in three Australian states; Victoria (VIC), New South Wales (NSW) and Western Australia (WA) for the period of 1990-1999. A total of 3398 driver fatalities were investigated which included 2609 car drivers, 650 motorcyclists and 139 truck drivers. Alcohol at or over 0.05 g/100ml (%) was present in 29.1% of all drivers. The highest prevalence was in car drivers (30.3%) and the lowest in truckers (8.6%). WA had the highest rate of alcohol presence of the three states (35.8%). Almost 10% of the cases involved both alcohol and drugs. Drugs (other than alcohol) were present in 26.7% of cases and psychotropic drugs in 23.5%. These drugs comprised cannabis (13.5%), opioids (4.9%), stimulants (4.1%), benzodiazepines (4.1%) and other psychotropic drugs (2.7%). 8.5% of all drivers tested positive for Delta(9)-tetrahydrocannabinol (THC) and the balance of cannabis positive drivers were positive to only the 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) metabolite. The range of THC blood concentrations in drivers was 0.1-228 ng/ml, with a median of 9 ng/ml. Opioids consisted mainly of morphine (n=84), codeine (n=89) and methadone (n=33), while stimulants consisted mainly of methamphetamine (n=51), MDMA (n=6), cocaine (n=5), and the ephedrines (n=61). The prevalence of drugs increased over the decade, particularly cannabis and opioids, while alcohol decreased. Cannabis had a larger prevalence in motorcyclists (22.2%), whereas stimulants had a much larger presence in truckers (23%).

Alcohol, illicit drugs and medicinal drugs in fatally injured drivers in Spain between 1991 and 2000

The aim of this study was to assess the presence of alcohol, illicit drugs and medicinal drugs among Spanish drivers involved in fatal road accidents between 1991 and 2000. Samples were obtained for 5745 drivers killed in road accidents from January 1991 to December 2000. Of the samples, 91.7% represented males and 8.3% females; 40.7% were under 30 years of age, 31.9% were under 31-50 years of age, 19.5% were over 51 years of age, and for 7.9% the age was unknown. Between 1991 and 2000, some type of psychoactive substance was detected among 50.1% of those drivers killed in road accidents, this being mainly alcohol (43.8%) and, less frequently, illicit drugs (8.8%) and medicinal drugs (4.7%). In all the cases, in which alcohol was detected, combined use with other substances accounted for only 12.5%, whilst in the case of illicit and medicinal drugs, figures representing combined use with other substances were 75.6% for the former and 65.8% for the latter. For one in every three cases (32.0%), a blood alcohol level over 0.8 g/l was recorded; cocaine (5.2%), opiates (3.2%) and cannabis (2.2%) were the three illicit drugs most frequently detected. Among medicinal drugs, were benzodiazepines (3.4%), anti-depressant drugs (0.6%) and analgesics (0.4%). The results show the frequent presence of psychoactive substances, particularly alcohol, among Spanish motor vehicle users involved in fatal road accidents. It should be pointed out that illicit and medicinal drugs in combination with other substances were a common feature.

Methamphetamine use in trauma patients: a population-based study

BACKGROUND

There are indications that methamphetamine production and illicit use are increasing. We investigated the epidemiology of methamphetamine use in trauma patients in an area of heavy methamphetamine prevalence.

STUDY DESIGN

This was a retrospective population-based review. We reviewed toxicology and alcohol test results in trauma patients admitted to the University of California, Davis, between 1989 and 1994 to the only trauma center serving a population of 1.1 million.

RESULTS

Positive methamphetamine rates nearly doubled between 1989 (7.4%) and 1994 (13.4%), compared with a minimal increase in cocaine rates (5.8% to 6.2%) and a decrease in blood alcohol rates (43% to 35%). Methamphetamine-positive patients were most likely to be Caucasian or Hispanic; cocaine-positive patients were most likely to be African American. Methamphetamine-positive patients were most commonly injured in motor vehicle collisions or motorcycle collisions; cocaine-positive patients were most commonly injured by assaults, gunshot wounds, or stab wounds. Cocaine positivity and alcohol positivity predicted a decreased need for emergency surgery and cocaine positivity predicted a decreased need for admission to the ICU.

CONCLUSIONS

Methamphetamine use in trauma patients increased markedly in our region between 1989 and 1994, alcohol rates decreased, and cocaine rates remained unchanged. Methamphetamine-positive patients had mechanisms of injury similar to those of alcohol-positive patients, so injury prevention strategies for methamphetamine should be patterned after strategies designed for alcohol.

Alcohol use among fatally injured drivers in Spain

Blood from 285 fatally injured drivers in Northern Spain was collected and tested for the presence of alcohol and drugs. Alcohol was detected in 50.5% of all fatalities. Alcohol alone was detected in 44.2% of all samples and in the remaining 6.3% another substance was found together with alcohol. Blood alcohol concentration was classified in different levels. It has been observed that in 35.4% of the cases the blood alcohol level was > or = 0.8 g/l, the legal limit in Spain for car drivers. Alcohol together with other substances was encountered in 18 cases, with medication in 22.2% (4 out of 18), alcohol with illegal drugs in 66.6% of the cases (12 out of 18), and alcohol with medicines and illegal drugs in 11.1% (2 out of 18). Cocaine was the most commonly detected drug. The study shows how widespread the incidence of a high level of alcohol concentration among drivers involved in fatal accidents in Spain.

Incidence of xenobiotics among drivers killed in single-vehicle crashes

The authors have performed a study of single-vehicle crashes (SVCs) in order to verify a correlation between the loss of vehicle control and the presence of drugs in the body. Overall, 129 cases were recorded and occurred in the catchment area of the Institute of Legal Medicine in Milan between 1986 to 1996. Among the 129 cases under study, respectively 121 men and eight women, 101 were car-drivers and 28 motor-cyclists. The median age was equal to 29 years, while the average age to 32.0 years (range 15-65 years). Fifty eight cases (45.0%) were "positive" for the presence of ethanol > or = 0.8 g/l or other drugs. The sample of "positive cases" was studied according to sex, age, day, hour and type of vehicle. Considering the cases with presence of ethanol, although under the legal limit (20 cases), the total amount of cases (78) becomes even more consistent. The amount of ethanol was found to be respectively 0.34 g/l in daily drivers and 0.87 g/l in nightly drivers (p < 0.01). Our considerations confirm the importance of toxicological analyses in the forensic investigation of traffic deaths being the sample under study recorded following criteria which minimised other possible factors effecting road accidents.