Alcohol Impairment Research Articles

Toking and driving: Characteristics of Canadian university students who drive after cannabis use—an exploratory pilot study

Cannabis use is increasingly prevalent among young adults in Canada. Due to cannabis’ impairment effects, driving under the influence of cannabis has recently developed into a traffic-safety concern, yet little is known about the specific circumstances and factors characterizing this behavior among young people. In this study, we interviewed a sample of university students (n = 45; age 18–28 years) in Toronto who had driven a car after cannabis use in the past year. The study collected information on respondents’ sociodemographic characteristics, cannabis and other drug use, cannabis use and driving (CUD) experiences, law enforcement and accident exposure, perceptions of cannabis and alcohol impairment effects as well as future anticipated substance use and driving behaviors. Results indicated that: CUD originated primarily from social settings; that impairment risks from cannabis were perceived to be low; and that the level of anticipated future CUD was high. Furthermore, high frequency of CUD in the past year was associated with high frequency of cannabis use. Interventions aiming at CUD among young people need to be anchored in the specific sociocultural settings of this behavior; targeted information needs to address cannabis’ impairment potential for driving; possibilities for harm-reduction measures for CUD need to be considered.

Behavioral Effects of Driver Distraction and Alcohol Impairment

There remains some debate regarding secondary task distractions, such as cell phones, as a risk factor in traffic crashes and their relative risk compared to existing factors, such as engagement in common in-vehicle tasks and alcohol impairment. Moreover, studies of driver impairment often investigate single risk factors rather than combined factors (e.g. distraction task while drunk). This study compared non-distracted driving in a motion-based driving simulator to distracted driving (hands-free cell phone conversations, common in-vehicle tasks) either while sober or combined with alcohol (BAC 0.08). The results indicated that during a car following scenario, drivers engaged in the conversations or completing in-vehicle tasks were more impaired than drivers that were not involved in any distraction task. Indeed, both the cell phone and in-vehicle sources of distraction were generally more impairing than intoxication at the legal limit.

Alcohol-induced impairment and enhancement of memory: A test of the interference theory

Many studies have found cognitive deficits related to alcohol consumption. However, few studies have studied cognitive performance when alcohol was administered after the to-be-remembered information was presented with memory testing occurring when participants are once again sober. The present study examined effects of alcohol on cognitive performance using a prose recall task during acute intoxication and a post-trial recall task for prose passages that had been presented before intoxication. Fifty-one men were given either 2.0 g/kg of 100 proof (50% absolute ethanol) vodka or a placebo. In the present study, evidence was found of acute alcohol impairment in prose memory, along with alcohol facilitation of memory on a post-trial task.

Are bad drivers more impaired by alcohol?: Sober driving precision predicts impairment from alcohol in a simulated driving task

The contribution of driver experience to risk for alcohol-related crashes is based on the tacit assumption that driver experience contributes to driver skill which could mediate the impairing effects of alcohol on driving performance. Surprisingly, few studies of alcohol effects on simulated driving performance have examined the role of driver skill as a mediator of the intensity of alcohol impairment. The present study examined the degree to which individual differences in driving skill mediated the intensity of impairment produced by a moderate dose of alcohol in a group of young adult drivers. Twenty-eight participants were familiarized with a simulated driving road test. After determining their baseline skill level, participants’ driving performance was re-tested under either an active dose of alcohol (0.65 g/kg) or a placebo. Results showed that alcohol reduced driving precision, as evident by the increased within-lane deviation observed under the drug. Moreover, those individuals with poorer baseline skill levels showed the greater impairments in response to alcohol. The results highlight the importance of understanding interactions between driver skill level and the effects of alcohol and possibly other drugs.

Compensating for alcohol-induced impairment of control: effects on inhibition and activation of behavior

Studies have shown that expectations of alcohol-induced impairment can produce adaptive responses to alcohol that reduce the degree of behavioral impairment displayed. However, compensatory effects have been variable for cognitive and psychomotor tasks. Using a model-driven approach to understanding behavioral control, the present study examined compensatory and impairment effects following the expectation and actual administration of alcohol on the ability to inhibit and activate behavior. Social drinkers (N=17) performed a cued go/no-go task that required quick responses to go targets and inhibition of responses to no-go targets under four conditions: no treatment, alcohol expectancy (placebo), 0.45 g/kg alcohol, and 0.65 g/kg alcohol. Inhibitory and activational aspects of behavioral control were impaired by both active doses of alcohol. Alcohol slowed response activation and increased failures to inhibit responses in a dose-dependent manner. Subjects also displayed a small, but statistically significant, compensatory improvement in inhibitory control in response to the expectation of alcohol. Moreover, individual differences in the compensatory response were related to differences in alcohol impairment. Those who displayed greater compensatory responses to placebo displayed the least impairment in response to alcohol. By modeling behavioral control as the net effect of countervailing activational and inhibitory influences, the study suggests that fundamental mechanisms of control might not display uniform compensatory reactions to alcohol-related cues. Greater consideration of how alcohol-related expectancies shape behaviors under the drug should lead to a better understanding of individual differences with respect to risk for alcohol abuse.

Temporal factors in motor vehicle crash deaths

Objective: To summarize fatal motor vehicle crash deaths in the United States by time of day, day of week, month, and season, and to determine why some days of the...

Trends in Motorcycle Fatalities Associated With Alcohol-Impaired Driving—United States, 1983-2003

Motorcycles are the most dangerous type of motor vehicle to drive. These vehicles are involved in fatal crashes at a rate of 35.0 per 100 million miles of travel, compared with a rate of 1.7 per 100 million miles of travel for passenger cars. The National Highway Traffic Safety Administration (NHTSA) has reported increasing numbers of motorcycle deaths associated with alcohol-impaired driving in recent years, especially among persons aged > or =40 years. To determine trends by age group in motorcycle fatalities overall and in those involving alcohol impairment, CDC analyzed data from the NHTSA Fatality Analysis Reporting System (FARS) for 1983, 1993, and 2003. This report summarizes the results of that analysis, which indicated that, during 1983-2003, the overall prevalence of elevated blood alcohol concentrations (BACs) among motorcycle drivers who died in crashes declined; however, the peak rate of death among alcohol-impaired motorcycle drivers shifted from those aged 20-24 years to those aged 40-44 years. Strong enforcement of existing BAC laws, together with other public health interventions aimed at motorcyclists, might reduce the crash mortality rate, especially among older drivers.

Visual–spatial attention in alcoholics and illicit stimulant abusers: effects of nicotine replacement

Reports of alcohol or illicit drug-related cognitive impairments have frequently disregarded the potentially confounding effects of smoking status and nicotine withdrawal on these measures. This study addressed this issue by measuring visual–spatial attention via an adaptation of the Posner paradigm in three groups of tobacco smokers: controls without a history of alcoholism or illicit drug use ( n=27; 20 male), chronic alcoholics ( n=22; 18 male), and illicit stimulant abusers ( n=36; 21 male). Throughout testing, nicotine levels were stabilized by the double-blind administration of a high (14 or 21 mg) or low (7 mg) dose transdermal nicotine patch. A significant effect of group was observed for number of correct responses to restriction trials ( F=5.48, 2/79 df; p=.006). Performance was normalized in the illicit stimulant group, and alcoholic participants exhibited superior performance relative to both illicit stimulant abusers ( p=.002) and controls ( p=.01). These findings support the hypothesis that nicotine may have a compensatory or normalizing effect on attentional functions in substance abusers. Whether these results reflect the central nervous system-activating effects of nicotine or merely alleviation of nicotine withdrawal is a topic of ongoing research.

Allostasis and dysregulation of corticotropin-releasing factor and neuropeptide Y systems: implications for the development of alcoholism

Alcoholism is a chronic relapsing disorder, accompanied by alterations in psychological and physiological functioning, which reaches an addictive state where an individual demonstrates uncontrollable compulsive alcohol drinking and impairment in social and occupational functioning. Withdrawal is one of the defining characteristics of dependence, characterized by impaired physiological function and enhanced negative affect, and is thought to be a major contributing factor to relapse. The negative emotional aspects of withdrawal appear to be more involved in continued alcohol craving because physical withdrawal symptoms are not highly correlated with relapse in alcoholics. Allostasis describes maintaining stability outside the homeostatic range by varying the internal milieu to match environmental demands. This concept has been applied to neurobiological models of drug addiction and is thought to contribute to the vulnerability of drug addicts to relapse, as addicts continue to use drugs in order to maintain their psychological state within a homeostatic range. With regard to alcohol, two neuropeptides appear to be involved in the regulation of alcohol-related stress, corticotropin-releasing factor (CRF), which is associated with an increased stress response and negative affect, and neuropeptide Y (NPY), a neuropeptide with anxiolytic properties. The hypothesis to be developed in the present review is that a dysregulation of the CRF and NPY systems significantly contributes to the motivational basis of continued alcohol-seeking behavior during alcohol dependence. It appears that increases in CRF contribute to the negative affective state that is strongly associated with alcohol withdrawal, and NPY provides a motivational basis to consume alcohol because the anxiolytic effects of alcohol, which are strongly associated with relapse, appear to be regulated in part by this neuropeptide.

Alcohol impairment of behavior in men and women: a reply to the commentaries

Alcohol impairment of behavior in men and women: a reply to the commentaries

Cognitive impairment and diffuse white matter atrophy in alcoholics

Objective Diffuse brain white matter atrophy is often seen in chronic alcoholics, but its relation with cognitive impairment remains to be solved. In order to address this issue, in alcoholics with cognitive impairment at different levels, we studied relations of the central sensory conduction time (CSCT) or brain magnetic resonance imaging (MRI) findings with the cognitive function. Methods Subjects were 35 alcoholics with mild cognitive impairment (mini-mental state examination score, MMSE, ≥24; mean±SD, 27.7±1.9), 12 with moderate to severe cognitive impairment (MMSE<24; 20.3±2.7), 15 with Alzheimer's disease (AD) (MMSE, 18.9±4.3) (disease control) and 20 healthy volunteers (MMSE, 28.5±1.6) (normal control). Median nerve SEPs were recorded in the all subjects, and the latencies and amplitudes of their N9, N11, P13/14, N20 and P25 components were measured. The ventriculocranial ratio (VCR) and the width of cortical sulci were measured on MRIs. These physiological parameters and MRI findings were compared between the 4 groups of the subject, and correlations between those all features were also analyzed. Results CSCT and VCR were significantly greater in alcoholics with moderate to severe cognitive impairment than those in the other 3 groups. Pearson's product–moment correlation analyses of the alcoholics disclosed that both the CSCT and VCR had significant negative correlations with the MMSE score. Moreover, the CSCT and VCR were positively correlated. Conclusions Both physiological and morphological estimates of the white matter function (CSCT and VCR) had a significant correlation with the cognitive dysfunction. Significance The diffuse white matter atrophy may be one of the factors causing cognitive impairment in chronic alcoholics.

Alcohol impairment of behavior in men and women.

Studies have shown that alcohol impairs the ability to inhibit behavioral responses in humans and some evidence suggests that men might display greater impairment than women. The present study compared men and women in the degree to which a moderate dose of alcohol impaired their inhibitory control at comparable blood alcohol concentrations. Twelve male and 12 female adult social drinkers received a moderate dose of alcohol (0.65 g/kg) and a placebo in a counterbalanced order and performed a cued go/no-go task that measured the ability to inhibit and execute behavioral responses. When the behavioral response was pre-potent (i.e. instigated), men displayed greater impairment of inhibitory control under alcohol than women. Men also reported greater levels of subjective stimulation from alcohol compared with women, who reported more sedation from the drug. A gender difference in alcohol impairment of inhibitory control could account for observations that disinhibited and aggressive behaviors under alcohol are more pronounced in men than in women.

Compromised pontocerebellar and cerebellothalamocortical systems: speculations on their contributions to cognitive and motor impairment in nonamnesic alcoholism.

Corticopontocerebellar and cerebellothalamocortical circuits underlie a wide range of neuropsychological processes compromised by alcoholism. The analyses herein tested whether abnormalities of volumes of brain structures forming nodes of these separate feed-forward and feedback systems are selectively related to each other and whether any of these noncortical regions can account for cognitive and motor deficits occurring as sequelae of chronic alcoholism. Regional brain measures originated from our prior neuroimaging studies, showing in alcoholics significant volume deficits in the principal structures of interest: cerebellar hemispheres, vermis, pons, and thalamus as well as prefrontal, frontal, and parietal cortex. Neuropsychological functions targeted for analysis-problem solving, visuospatial ability, and static postural stability-showed 0.6 to 1.6 SD deficits in these alcoholic men. In alcoholics, the patterns of correlations were consistent with dissociation of thalamic and pontine circuitry. Pontine and thalamic volumes were not correlated with each other. Pontine volumes correlated with white matter volumes of anterior superior vermis and gray and white matter volumes of the cerebellar hemispheres but not with cortical regional volumes. Thalamic volumes correlated with gray matter volumes of the cerebellar hemispheres, parietal cortex, and inferior posterior vermian lobule, which itself correlated with parietal, prefrontal, and frontal cortical volumes. Controls did not show these correlational patterns. Brain structure-function relationships in alcoholics examined with multiple regression identified anterior vermian but not prefrontal or parietal volume as a unique predictor of balance scores; vermian and thalamic but not prefrontal cortical volumes as predictors of card sorting scores; and cerebellar hemispheric white matter but not parietal cortical volume as a predictor of visuospatial ability. Each major node of frontocerebellar circuitry shows volume deficits in alcoholics but can be independently compromised. Disruption of these circuits may underlie alcoholism-related neuropsychological deficits, either by abnormalities present in individual nodes or by disconnection via interruption of selective circuitry.

Preresponse cues reduce the impairing effects of alcohol on the execution and suppression of responses.

The present study examined the effects of alcohol on the ability to execute and inhibit behavior in a context in which preliminary information signaled the likelihood that a response should be executed or suppressed. Social drinkers (N = 12) performed a cued go/no-go task that required quick responses to go targets and suppression of responses to no-go targets. Performance was tested under 3 doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Alcohol had no effect on inhibition and execution when cues correctly signaled these actions. By contrast, alcohol impaired inhibition and execution in a dose-dependent manner when cues incorrectly signaled actions. These findings are consistent with a resource limitation account of alcohol impairment. Language: en

Views of U.S. drivers about driving safety

Problem: To assess how drivers view dangers on the highway, what motivates them to drive safely, how they say they reduce their crash and injury risk, and how they rate their own driving skills. Results: Most drivers rated their skills as better than average. The biggest motivating factor for safe driving was concern for safety of others in their vehicle, followed by negative outcomes such as being in a crash, increased insurance costs, and fines. The greatest threats to their safety were thought to be other drivers' actions that increase crash risk such as alcohol impairment or running red lights. In terms of reducing crashes and injuries, drivers tended to focus on actions they could take such as driving defensively or using seat belts. There was less recognition of the role of vehicles and vehicle features in crash or injury prevention. Impact on research, practice, and policy: Knowing how drivers view themselves and others, their concerns, and their motivations and techniques for staying out of trouble on the roads provides insight into the difficulty of changing driving practices.

Electrophysiological evidence of abnormal activation of the cerebral network of involuntary attention in alcoholism.

Increased distractibility is a common impairment in alcoholism, but objective evidence has remained elusive. Here, a task designed to investigate with event-related brain potentials (ERPs) the neural mechanism underlying distraction was used to show abnormal involuntary orienting of attention in chronic alcoholism. Fifteen alcoholics and 17 matched healthy controls were instructed to ignore auditory stimuli while concentrating in the discrimination of immediately following visual stimuli. The auditory sequences contained repetitive standard tones occasionally replaced by deviant tones of slightly higher frequency, or by complex novel sounds. Deviant tones and novel sounds distracted visual performance, i.e. increased reaction time to visual stimuli, similarly in patients and controls. Compared to controls, however, alcoholics showed ERP abnormalities, i.e. enhanced P3a amplitudes over the left frontal region, and a positive posterior deflection instead of the frontally distributed reorienting negativity (RON). The enhanced P3a to novelty and subsequent positive wave instead of RON in alcoholics suggests encoding into working memory of task-irrelevant auditory events and provides neurophysiological markers of impaired involuntary attention mechanisms in chronic alcoholism.

Concussion, alcohol, fatigue and performance impairment

Concussion, alcohol, fatigue and performance impairment

Effectiveness of Sobriety Checkpoints for Reducing Alcohol-Involved Crashes

The goal of sobriety checkpoints is to deter drinking and driving by systematically stopping drivers for assessment of alcohol impairment, thus increasing the perceived risk of arrest for alcohol-impaired driving. This review examines the effectiveness of random breath testing (RBT) checkpoints, at which all drivers stopped are given breath tests for blood alcohol levels, and selective breath testing (SBT) checkpoints, at which police must have reason to suspect the driver has been drinking before demanding a breath test. A systematic review of the effectiveness of sobriety checkpoints in reducing alcohol-involved crashes and associated injuries and fatalities was conducted using the methodology developed for the Guide to Community Preventive Services (Community Guide) . Substantial reductions in crashes were observed for both checkpoint types across various outcome measures and time periods. Results suggest that both RBT and SBT checkpoints can play an important role in preventing alcohol-related crashes and associated injuries.

Does caffeine counteract alcohol-induced impairment? The ironic effects of expectancy.

Studies have shown that expectations of alcohol-induced impairment can produce adaptive responses to alcohol that reduce the degree of behavioral impairment displayed. The present study tested psychomotor performance following combined caffeine and alcohol administration in 42 social drinkers (23 men). Subjects were led to expect either that caffeine would antagonize alcohol-induced impairment or that it would have no effect. The study tested the hypothesis that drinkers who expected an antagonist effect of caffeine would display greater alcohol impairment than those who expected no antagonist effect. Groups practiced a pursuit rotor task and received a moderate dose of alcohol (0.65 g/kg) combined with either 4.0 mg/kg caffeine or placebo caffeine. Some groups were led to expect that caffeine would counteract the impairing effect of alcohol and others were led to expect no counteracting effect. Psychomotor performance was then tested over a 3-hour period. In accord with the hypothesis, groups led to expect counteracting effects of caffeine displayed greater impairment than those led to expect no counteraction. Caffeine had no significant antagonist effect on alcohol impairment. The findings suggest that compensation for alcohol impairment occurs when drinkers hold clear expectations that the drug will disrupt performance. When no such clear expectation exists, no compensatory response occurs and the impairing effects of alcohol are observed.

An Analysis of in-Flight Impairment and Incapacitation in Fatal General Aviation Accidents (1990–1998)

In-flight impairment and incapacitation are defined as states wherein the pilot's ability to effectively control the aircraft is adversely affected. They are of special concern in general aviation given there may be no second pilot to take over the controls. The purpose of the present study was to examine the characteristics of fatal general aviation accidents associated with impairment and incapacitation. A comprehensive review of 2,696 fatal general aviation accidents from 1990–1998 using database records maintained by the NTSB and FAA yielded 216 accidents (8.01%) that had some form of impairment/incapacitation or physiological causes mentioned in the accident report. Impairment due to drugs ( n = 88, 40.7%) and alcohol ( n = 68, 31.5%) were the most common causes. Cardiovascular causes were cited in 12.03% (n = 26) of the cases. Significant relationships were observed between age and impairment/incapacitation due to alcohol, drugs, and cardiovascular causes. Some disparities were observed between the prevalence of alcohol in toxicology samples and alcohol impairment being cited in the accident report as a contributory factor. The analysis provides some insight into the possible causes of pilot impairment and incapacitation in general aviation. Education and risk management training may serve as effective interventions.