Drugs, alcohol and road accidents in Tasmania

The effect of cannabis compared with alcohol on driving

The prevalence of both alcohol and cannabis use and the high morbidity associated with motor vehicle crashes has lead to a plethora of research on the link between the two. Drunk drivers are involved in 25% of motor vehicle fatalities, and many accidents involve drivers who test positive for cannabis. Cannabis and alcohol acutely impair several driving-related skills in a dose-related fashion, but the effects of cannabis vary more between individuals than they do with alcohol because of tolerance, differences in smoking technique, and different absorptions of Delta(9)-tetrahydrocannabinol (THC), the active ingredient in marijuana. Detrimental effects of cannabis use vary in a dose-related fashion, and are more pronounced with highly automatic driving functions than with more complex tasks that require conscious control, whereas alcohol produces an opposite pattern of impairment. Because of both this and an increased awareness that they are impaired, marijuana smokers tend to compensate effectively while driving by utilizing a variety of behavioral strategies. Combining marijuana with alcohol eliminates the ability to use such strategies effectively, however, and results in impairment even at doses which would be insignificant were they of either drug alone. Epidemiological studies have been inconclusive regarding whether cannabis use causes an increased risk of accidents; in contrast, unanimity exists that alcohol use increases crash risk. Furthermore, the risk from driving under the influence of both alcohol and cannabis is greater than the risk of driving under the influence of either alone. Future research should focus on resolving contradictions posed by previous studies, and patients who smoke cannabis should be counseled to wait several hours before driving, and avoid combining the two drugs.

Benzodiazepine drugs in Australia: associated mortality and morbidity

The use of benzodiazepine drugs in Australia results not only in widespread therapeutic benefits but also in harmful outcomes at both an individual and societal level. Accurate measurement of the level of harm has been precluded by a lack of robust data relating to the use of these drugs and to the resulting adverse consequences. This paper examines existing mortality and morbidity data, comments upon the available data sources and recommends areas where research is needed in order to clarify the relationship between the use of benzodiazepines and associated adverse effects.

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.

A review of drug use and driving: epidemiology, impairment, risk factors and risk perceptions

The existing literature on the prevalence of drug driving, the effects of drugs on driving performance, risk factors and risk perceptions associated with drug driving was reviewed. The 12-month prevalence of drug driving among the general population is approximately 4%. Drugs are detected commonly among those involved in motor vehicle accidents, with studies reporting up to 25% of accident-involved drivers positive for drugs. Cannabis is generally the most common drug detected in accident-involved drivers, followed by benzodiazepines, cocaine, amphetamines and opioids. Polydrug use is common among accident-involved drivers. Studies of impairment indicate an undeniable association between alcohol and driving impairment. There is also evidence that cannabis and benzodiazepines increase accident risk. The most equivocal evidence surrounds opioids and stimulants. It is apparent that drugs in combination with alcohol, and multiple drugs, present an even greater risk. Demographically, young males are over-represented among drug drivers. Although there is an association between alcohol use problems and drink driving, it is unclear whether such an association exists between drug use problems and drug driving. Evidence surrounding psychosocial factors and driving behaviour is also equivocal at this stage. While most drivers perceive drug driving to be dangerous and unacceptable, there is less concern about impaired driving among drug drivers and drink drivers than from those who have not engaged in impaired driving. Risk perceptions differ according to drug type, with certain drugs (e.g. cannabis) seen as producing less impairment than others (e.g. alcohol). It is concluded that drug driving is a significant problem, both in terms of a general public health issue and as a specific concern for drug users.

The role of captodiamine in the withdrawal from long-term benzodiazepine treatment

BACKGROUND AND OBJECTIVES

Discontinuation of benzodiazepines can be associated with the emergence of a withdrawal syndrome which compromises successful termination of treatment. The objective of the present study was to evaluate whether a six week administration of captodiamine during benzodiazepine discontinuation could prevent emergence of a benzodiazepine withdrawal syndrome and thus facilitate discontinuation of these drugs.

SUBJECTS AND METHODS

A controlled, randomised, double-blind trial of captodiamine versus placebo was conducted in 81 subjects presenting mild to moderate anxiety and treated for at least 6 months with a stable dose of benzodiazepine. Each subject was gradually weaned from benzodiazepines over a 14 day period using a tapering dose schedule and received captodiamine (150 mg/d) or placebo for 45 days from the beginning of the weaning period.

OUTCOME MEASURES

The primary outcome criterion was the extent of withdrawal symptoms assessed using the Tyrer Benzodiazepine Withdrawal Symptom Questionnaire. Secondary outcome criteria were; self-evaluation of tension, anxiety, drowsiness and slowing of physical and mental performance using visual analogue scales; quality of sleep using the Spiegel questionnaire; anxiety using the Hamilton Anxiety Rating Scale; and cognitive function using a driving stimulation test.

RESULTS

Analysis of the primary study criterion revealed a statistically significant difference (p < 0.0001) in the emergence of withdrawal symptoms between the two groups in favour of captodiamine at two, six and eight weeks following initiation of therapy. These results were supported by significant beneficial effects of captodiamine on the majority of secondary outcome measures. The switch to captodiamine was associated with an improvement in vigilance, which may be an advantage for the overall safety of the anxiolytic treatment, for example with regard to road safety. Discontinuation of captodiamine was not associated with the emergence of rebound anxiety.

CONCLUSION

Captodiamine represents an interesting strategy for achieving benzodiazepine substitution with a low risk of dependence or impairment of cognitive function. Further clinical studies addressing the anxiolytic activity and safety of captodiamine in such subjects are merited.

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.

The interactive effects of alcohol and temazepam on P300 and reaction time

The present research investigated the separate and interactive effects of the minor tranquilizer, temazepam, and a low dose of alcohol on the amplitude and latency of P300 and on reaction time. Twenty-four participants completed four drug treatments in a repeated measures design. The four drug treatments, organised as a fully repeated 2 x 2 design, included a placebo condition, an alcohol only condition, a temazepam only condition, and an alcohol and temazepam combined condition. Event-related potentials were recorded from midline sites Fz, Cz, and Pz within an oddball paradigm. The results indicated that temazepam, with or without the presence of alcohol, reduced P300 amplitude. Alcohol, on the other hand, with or without the presence of temazepam, affected processing speed and stimulus evaluation as indexed by reaction time and P300 latency. At the low dose levels used in this experiment alcohol and temazepam appear not to interact, which suggests that they affect different aspects of processing in the central nervous system.

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.

Physical and mental health problems associated with the use of alcohol and drugs

The nature and extent of treated health problems in patients with problems related to the use of alcohol and drugs (including both licit and illicit drugs) were compared with the morbidity levels of all patients treated for all conditions in Canada. The morbidity experience of all patients with alcohol or drug (A/D) diagnoses treated as inpatients (n = 52,200 cases) in all Ontario hospitals in 1985-1986 (based on Hospital Medical Records Institute [HMRI] data) was compared with that of the total population of all inpatients treated in all Canadian hospitals using age-sex standardized morbidity ratios (SMR) and adjusting for multiple diagnoses. Of A/D cases, 32% were admitted with a primary A/D diagnosis and 68% with a secondary A/D diagnosis; 17% of A/D cases had multiple A/D diagnosis. On average, cases with a primary A/D diagnosis had 29% more diagnoses per case than all cases treated in Ontario. SMRs were highest for cases with diagnoses relating to the use or misuse of licit drugs (SMR = 13.32 and 3.51 for those with primary and secondary drug diagnoses, respectively), intermediate for illicit drug cases (SMR = 8.87 vs. 4.74 for primary and secondary diagnoses, respectively), and lowest for patients with alcohol diagnoses (SMR = 6.68 and 4.12 for primary and secondary diagnoses, respectively). Excess morbidity for alcohol cases affected more diagnostic categories and body systems, being at a higher level than for drug cases. Alcohol or drug cases had particularly high SMRs for mental disorders, infectious and parasitic conditions, and injury and poisoning diagnoses. Alcohol or drug cases had reduced reproductive morbidity: for complications of pregnancy, childbirth, and the puerperium, SMR = 0.04 to 0.24 for cases with primary A/D diagnoses and SMR = 0.12 to 0.89 for those with secondary A/D diagnoses. Cases with drug diagnoses had a considerable reduction in SMR for certain conditions originating in the perinatal period: SMR = 0.0 for cases with primary drug diagnoses and SMR = 0.0 for secondary illicit drug diagnoses cases and SMR = 0.18 for secondary licit drug diagnoses cases.

Visual search and urban driving under the influence of marijuana and alcohol

The purpose of the present study was to assess the effects of low doses of marijuana and alcohol, and their combination, on visual search at intersections and on general driving proficiency in the City Driving Test. Sixteen recreational users of alcohol and marijuana (eight males and eight females) were treated with these substances or placebo according to a balanced, 4-way, cross-over, observer- and subject-blind design. On separate evenings, subjects received weight-calibrated doses of THC, alcohol or placebo in each of the following treatment conditions: alcohol placebo + THC placebo, alcohol + THC placebo, THC 100 &mgr;g/kg + alcohol placebo, THC 100 &mgr;g/kg + alcohol. Alcohol doses administered were sufficient for achieving a blood alcohol concentration (BAC) of about 0.05 g/dl. Initial drinking preceded smoking by one hour. The City Driving Test commenced 15 minutes after smoking and lasted 45 minutes. The test was conducted over a fixed route within the city limits of Maastricht. An eye movement recording system was mounted on each subject's head for providing relative frequency measures of appropriate visual search at intersections. General driving quality was rated by a licensed driving instructor on a shortened version of the Royal Dutch Tourist Association's Driving Proficiency Test. After placebo treatment subjects searched for traffic approaching from side streets on the right in 84% of all cases. Visual search frequency in these subjects did not change when they were treated with alcohol or marijuana alone. However, when treated with the combination of alcohol and marijuana, the frequency of visual search dropped by 3%. Performance as rated on the Driving Proficiency Scale did not differ between treatments. It was concluded that the effects of low doses of THC (100 &mgr;g/kg) and alcohol (BAC < 0.05 g/dl) on higher-level driving skills as measured in the present study are minimal. Copyright 2001 John Wiley & Sons, Ltd.

Marijuana, alcohol and actual driving performance

The objective of the current study was to assess the separate and combined effects of marijuana and alcohol on actual driving performance. Eighteen subjects were treated with drugs and placebo according to a balanced, 6-way, crossover design. On separate evenings they were given weight calibrated Delta(9)-tetrahydrocannabinol (THC) doses of 0, 100 and 200 &mgr;g/kg with and without an alcohol dose sufficient for achieving blood alcohol concentrations (BAC) of 0.04 g/dl while performing a Road Tracking and Car Following Test in normal traffic. Main outcome measures were standard deviation of lateral position (SDLP), time driven out of lane (TOL), reaction time (RT) and standard deviation of headway (SDH). Both THC doses alone, and alcohol alone, significantly impaired the subjects performances in both driving tests. Performance deficits were minor after alcohol and moderate after both THC doses. Combining THC with alcohol dramatically impaired driving performance. Alcohol combined with THC 100 and 200 &mgr;g/kg produced a rise in SDLP the equivalent of that associated with BAC=0.09 and 0.14 g/dl, respectively. Mean TOL rose exponentially with SDLP. Relative to placebo mean RT lengthened by 1.6 s under the combined influence of alcohol and THC 200 &mgr;g/kg. Changes in SDH ranged between 0.9 and 3.8 m. Low doses of THC moderately impair driving performance when given alone but severely impair driving performance in combination with a low dose of alcohol. Copyright 2000 John Wiley & Sons, Ltd.

Medications as risk factors for farm injury

A case-control study was used to determine whether cases of farm injury were more likely than controls to have been regularly exposed to certain types of medication including those that cause side effects which may predispose to injury. Persons reporting an injury (n = 176) were identified in a population-based mail survey of people on 1364 Ontario farms, and compared to people without injuries using a 4:1 control: case ratio. Bivariate, stratified, and multivariable analyses were used to quantify the strength of associations between exposures to certain medications and the occurrence of farm injury. Those who regularly used certain types of medication were separated into two groups: people who used the medications in isolation, and those who used the medications in combination with other medications. Response to the survey was 77.3% among cases and 82.6% among controls. Strong and statistically significant increases in risk for injury were observed in association with the regular use of stomach remedies or laxatives by males (OR 2.8; 95% CI: 1.0,7.7), and regular use of heart of circulatory medications by men over the age of 45 (OR 4.2; 95% CI: 1.2,14.7). The identified associations remained after adjustment for age, co-morbidity, tillable farm acreage, education, income, alcohol consumption and tobacco use. Several possible explanations for the occurrence of the identified associations, other than the etiological hypothesis originally advanced, are discussed.

P300 and traffic scenes: the effect of temazepam

The present research investigated the effects of a minor tranquillizer (temazepam) on P300 in a paradigm that may be relevant for traffic behaviour. Because accident scenes have not been used previously in P300 research, Experiment 1 (n = 8) examined whether the P300 elicited by safe traffic scenes and scenes of imminent road accidents were sensitive to the probability of occurrence. Event-related potentials were recorded from C3, Cz, C4, P3, Pz and P4 within an oddball paradigm. The type of stimulus to which subjects responded (pictures of imminent accidents or safe road scenes) was crossed with the probability (0.1 or 0.5) of the relevant (to which a response was required) event. The results indicated that P300 amplitude increased with decreasing probability of the relevant stimulus and that P300 was most pronounced at Pz. Experiment 2 (n = 12) employed a drug treatment (10 mg temazepam) and a placebo treatment (100 mg Vitamin E). An oddball paradigm with a probability of the relevant stimulus of 0.1 was used and P300 was recorded from Cz, C3, C4, Pz, P3 and P4. Generally, the ingestion of temazepam decreased P300 amplitude and increased P300 latency at all sites. Reaction time, on the other hand, was not influenced by drug administration. The data demonstrate the clear effect of minor tranquillizers on the psychological processes associated with P300.

Automated screening procedure using gas chromatography-mass spectrometry for identification of drugs after their extraction from biological samples

A novel analytical screening procedure has been developed, using computer-controlled gas chromatography-mass spectrometry (GC-MS), to detect 120 drugs of interest to road safety. This paper describes GC-MS methodology suitable for use on extracts of biological origin, while extraction procedures will be the subject of a future communication. The method was devised to identify drugs in extracts of blood samples, as part of an investigation into the involvement of drugs, other than alcohol, in road accidents. The method could be adapted to screen for other substances. The method depends on a "macro" program which was written to automate the search of GC-MS data for target drugs. The strategy used was to initially search for each drug in the database by monitoring for a single characteristic ion at the expected retention time. If a peak is found in this first mass chromatogram, a peak for a second characteristic ion is sought within 0.02 min of the first and, if found, the ratio of peak areas calculated. Probable drug identification is based on the simultaneous appearance of peaks for both characteristic ions at the expected retention time and in the correct ratio. If the ratio is outside acceptable limits, a suspected drug (requiring further investigation) is reported. The search macro can use either full mass spectra or, for enhanced sensitivity, data from selected ion monitoring (which requires switching between groups of ions during data acquisition). Quantitative data can be obtained in the usual way by the addition of internal standards.

Behavioral correlates and staff recognition of alcohol use in a university hospital trauma service

Hospital course and admission blood alcohol levels were compared in 242 consecutive adult trauma admissions. A 33% overall intoxication rate was found. Intoxicated patients were more likely to be young, male, and Hispanic or black and to be involved in fights, stabbings, and automobile accidents in which they were presumed to be at fault. These patients were also more likely to manifest disruptive behavior in the emergency room. Disruptive behavior on the ward was not correlated with alcohol intoxication at admission, but was correlated with the history of head injury. Staff recognition of intoxication was high, but only about 7% of the patients who were intoxicated at admission were referred to alcohol treatment programs. More frequent referrals for such treatment might decrease trauma center admissions and the high costs associated with them.

Attitudes to alcoholism in a Sydney teaching hospital

The physical and psychosocial tolls that are attributable to alcohol are well-documented. However, our community has been slow to respond to this serious problem. A survey of attitudes to alcoholism at a Sydney teaching hospital found an acceptance of the disease model and an acknowledgement of alcohol as Australia's main problem drug. The vast majority of respondents felt that the National Campaign against Drug Abuse had paid inadequate attention to alcohol.

Prescribing of noncontraceptive estrogens and progestins in the United States, 1974-86

This paper describes changes in the prescribing of noncontraceptive estrogens and progestins, using data from pharmaceutical marketing surveys. The number of estrogen prescriptions decreased from 1975 to 1980, and then increased through 1986. Progestin use has increased since 1982; concomitant use of estrogens and progestins increased over time and was common in 1986. The trends suggest that the use of estrogens, particularly the combined use of estrogens and progestins, will continue to increase.

Blood alcohol measurements in the emergency department: who needs them?

We surveyed North Carolina emergency physicians to determine current medical practices regarding the use of blood alcohol concentrations using a hypothetical scenario. Most physicians (88 per cent) would not have obtained blood alcohol concentrations in a patient who had alcohol on his breath but was coherent and cooperative. For marginally impaired patients, more liberal use of blood alcohol concentrations and explicit instructions to avoid driving while impaired might improve patient care and promote highway safety.