Cognitive performance measured on the ascending and descending limb of the blood alcohol curve

High-intensity drinking and hours spent drinking

BACKGROUND

High-intensity drinking (HID) is associated with negative consequences, but it remains unclear whether a time qualifier (i.e., time spent drinking) is needed to identify individuals at highest risk. To improve the measurement and conceptualization of HID, we examined the utility of adding a time qualifier to define what constitutes an occasion of HID using repeated daily surveys in a sample of young adults.

METHODS

Participants were selected from a nationally representative sample of 12th-grade students in the United States who participated in the Monitoring the Future (MTF) study in Spring 2018. In 2019 and 2020, young adults (at modal ages 19-20) responded to annual and daily (14 consecutive days per year) online surveys about their alcohol use.

RESULTS

When we compared moderate drinking days (less than 4/5 drinks for women/men), binge drinking days (4-7/5-9 drinks), and HID days (8+/10+ drinks), HID days had the longest duration of drinking (5.2 h), highest peak estimated blood alcohol concentration (eBAC, 0.30%), and greatest drinking pace (2.58 drinks/h). HID was associated with a greater number of negative consequences than either moderate or binge drinking; adjusting for time spent drinking did not impact this interpretation. HID was reported on 10.9% of days; when defined as 8/10+ drinks in 4 h or 2 h, HID was reported on 4.8% and 1.0% of days, respectively. Nearly all differences in eBAC and negative consequences persisted across drinking intensity despite the introduction of time constraints.

CONCLUSIONS

HID days were characterized by both a longer time spent drinking and a more rapid pace of drinking. Adding a time qualifier to the definition of HID would restrict variability by only describing the minority of days and does not improve the distinctions among levels of risk.

Characterising patterns of alcohol use among heavy drinkers: A cluster analysis utilising alcohol biosensor data

INTRODUCTION

Previous research has predominately relied on person-level or single characteristics of drinking episodes to characterise patterns of drinking that may confer risk. This research often relies on self-report measures. Advancements in wearable alcohol biosensors provide a multi-faceted objective measure of drinking. The current study aimed to characterise drinking episodes using data derived from a wearable alcohol biosensor.

METHODS

Participants (n = 45) were adult heavy drinkers who wore the Secure Continuous Remote Alcohol Monitoring (SCRAM) bracelet and reported on their drinking behaviours. Cluster analysis was used to evaluate unique combinations of alcohol episode characteristics. Associations between clusters and self-reported person and event-level factors were also examined in univariable and multivariable models.

RESULTS

Results suggested three unique clusters: Cluster 1 (most common, slowest rate of rise to and decline from peak), Cluster 2 (highest peak transdermal alcohol concentration and area under the curve) and Cluster 3 (fastest rate of decline from peak). Univariable analyses distinguished Cluster 1 as having fewer self-reported drinks and fewer episodes that occurred on weekends relative to Cluster 2. The effect for number of drinks remained in multivariable analyses.

DISCUSSION AND CONCLUSIONS

This is the first study to characterise drinking patterns at the event-level using objective data. Results suggest that it is possible to distinguish drinking episodes based on several characteristics derived from wearable alcohol biosensors. This examination lays the groundwork for future studies to characterise patterns of drinking and their association with consequences of drinking behaviour.

How much and how fast: Alcohol consumption patterns, drinking-episode affect, and next-day consequences in the daily life of underage heavy drinkers

BACKGROUND

Understanding how alcohol consumption patterns are associated with negative and positive outcomes can inform efforts to reduce negative consequences through modification of those patterns. This is important in underage drinkers, many of whom drink heavily despite negative consequences. Most work has focused on the amount of alcohol consumed, but amount provides limited information about consumption patterns compared to rate of consumption, or how fast individuals drink. We therefore examined associations of both amount and rate of consumption with negative and positive outcomes (immediate affective states and next-morning consequences) in daily life.

METHOD

Ninety-five college students aged 18-20 years completed ecological momentary assessment over 28 days. Participants reported number of standard drinks consumed and positive and negative affect hourly within drinking episodes. Estimated blood alcohol concentration (eBAC) values were used to create amount and rate of consumption indicators. Each morning after drinking, participants reported negative (e.g., blackout, hangover) and positive (e.g., new friend, making others laugh) consequences.

RESULTS

Within drinking episodes, multilevel models showed faster consumption was associated with reduced negative affect and both larger amount and faster consumption were associated with greater positive affect. Further, amount and rate were both associated with greater likelihood of a negative consequence the next morning. Rate, but not amount, was associated with more positive consequences.

CONCLUSIONS

Not only how much but also how fast individuals drink may be important for the positive and negative outcomes they experience. Interventions to reduce negative alcohol-related outcomes should consider not only amount, but also rate of consumption.

Rate of alcohol consumption in the daily life of adolescents and emerging adults

RATIONALE

Alcohol consumption in adolescents and emerging adults is a significant issue. However, our understanding of the topography of alcohol use within drinking episodes in this population is at a nascent stage.

OBJECTIVES

This study characterized rate of alcohol consumption in the daily lives of problem drinkers ages 16-24 years (N = 75). We examined whether AUD symptoms and the presence of peers, factors relevant to alcohol consumption in youth, were associated with rate of consumption.

METHODS

Ecological momentary assessment (EMA) was used (N_observations = 799). Rate of consumption was defined as change in estimated blood alcohol concentration (eBAC) relative to the start of the drinking episode. Piecewise multi-level modeling was used to test hypotheses. As a comparison, we examined whether indicators of quantity and frequency (Q-F) were associated with AUD symptoms and presence of peers.

RESULTS

For all participants, eBAC increased sharply early in the episode, then plateaued. Participants with more AUD symptoms or who were in the presence of peers had significantly steeper increases in eBAC over the early part of the episode. Participants with more AUD symptoms were also more likely to engage in binge-like behavior. For Q-F, only peak eBAC and peak number of standard drinks were associated with AUD symptoms, and not presence of peers.

CONCLUSIONS

Findings highlight the value of rate of consumption as an indicator of use in youth, one sensitive to the influence of relevant person-level and situational factors. Intervention efforts may benefit from targeting the speed at which youth drink.

Elevated rate of alcohol consumption in borderline personality disorder patients in daily life

RATIONALE

Borderline personality disorder (BPD) is highly associated with alcohol use disorder, but little is known about how BPD individuals consume alcohol or the immediate effects of their consumption. There is therefore a need for research investigating drinking behavior in BPD.

OBJECTIVES

The current study examined rate of alcohol consumption in BPD (N = 54) and community individuals (COM; N = 59) within ecologically valid drinking episodes. We hypothesized that rate of consumption would be elevated in BPD individuals. We further hypothesized that rate of consumption would be positively associated with subjective stimulation, but not sedation, and that stimulation would be associated with increased positive affect (PA) and reduced negative affect (NA).

METHODS

Ambulatory assessment was used to assess rate of consumption, subjective alcohol response, and affect in the moment (N observations = 3444). Rate of consumption was defined as change in estimated blood alcohol concentration (eBAC) relative to drinking episode start. Multilevel modeling was used to test hypotheses.

RESULTS

As hypothesized, BPD individuals demonstrated a faster increase in eBAC than COM individuals. Rate of consumption was associated with subjective stimulation, but not sedation, in both groups. Stimulation was associated with increased PA in both groups and reduced NA in the BPD group.

CONCLUSIONS

BPD individuals consumed alcohol more rapidly than COM individuals. Faster consumption may serve as a means for BPD individuals to maximize the rewarding pharmacological effects of alcohol and to increase positive and reduce negative affect.

A systematic review of the evidence for acute tolerance to alcohol - the "Mellanby effect"

OBJECTIVE

To review the evidence for "the Mellanby effect", that is, whether the response to a given blood alcohol concentration (BAC) is more marked when BAC is rising than at the same concentration when BAC is falling.

METHODS

We systematically searched the databases EMBASE, Medline, and Scopus up to and including December 2016 using text words "tolerance", "ascending", "descending" or "Mellanby" with Medline term "exp *alcohol/" or "exp *drinking behavior/" or equivalent. Articles were identified for further examination by title or abstract; full text articles were retained for analysis if they dealt with acute (within dose) alcohol tolerance in human subjects and provided quantitative data on both the ascending and descending parts of the BAC-time curve. Reference lists of identified works were scanned for other potentially relevant material. We extracted and analyzed data on the subjective and objective assessment of alcohol effects.

RESULTS

We identified and screened 386 unique articles, of which 127 full-text articles were assessed; one provided no qualitative results, 62 involved no human study, 25 did not consider acute tolerance within dose, and 13 failed to provide data on both ascending and descending BAC. We extracted data from the 26 remaining articles. The studies were highly heterogeneous. Most were small, examining a total of 770 subjects, of whom 564 received alcohol and were analyzed in groups of median size 10 (range 5-38), sometimes subdivided on the basis of drinking or family history. Subjects were often young white men. Doses of alcohol and rates of administration differed. Performance was assessed by at least 26 different methods, some of which measured many variables. We examined only results of studies which compared results for a given alcohol concentration (C) measured on the ascending limb (C_up) and the descending limb (C_down) of the BAC-time curve, whether in paired or parallel-group studies. When subjects were given alcohol in more than one session, we considered results from the first session only. Rating at C_down was better than at C_up for some measures, as expected if the Mellanby effect were operating. For example, subjects rated themselves less intoxicated on the descending limb than at the same concentration on the ascending limb in 12/13 trials including 229 subjects that gave statistically significant results. In 9 trials with a total of 139 subjects, mean difference could be calculated; weighted for study size, it was 29% [range 24-74%]. Willingness to drive was significantly greater in 4 of 6 studies including a total of 105 subjects; weighted mean difference increased by 207% [range 79-300%]. By contrast, measure of driving ability in three groups of a total of 200 trials in 57 subjects showed worse performance by a weighted mean of 96% [range 3-566%]. In three trials that tested inhibitory control (cued go or no-go response times), weighted mean performance was 30% [range 14-65%] worse on the descending limb.

CONCLUSIONS

The "Mellanby effect" has been demonstrated for subjective intoxication and willingness to drive, both of which are more affected at a stated ethanol concentration when BAC is rising than at the same concentration when BAC is falling. By contrast, objective measures of skills necessary for safe driving, such as response to inhibitory cues and skills measured on driving simulators, were generally worse on the descending part of the BAC-time curve for the same BAC.

Impaired perceptual judgment at low blood alcohol concentrations

Males and females show different patterns of cognitive impairment when blood alcohol concentrations (BACs) are high. To investigate whether gender differences persist at low BACs, cognitive impairment was tested in 21 participants (11 female, 10 male) using a brief computerized perceptual judgment task that provides error rate and response time data. Participants consumed a measured dose of alcohol (average peak BAC: females: 0.052 g/100 mL, males: 0.055 g/100 mL), and were tested at four time points spanning both the rising and falling limbs of the BAC curve, in addition to a prealcohol time point. Comparisons were made against performance of these same participants at equivalent time points in an alcohol-free control condition. Males and females displayed a trend toward slower responses and more errors, even when mildly intoxicated. These data indicate that cognitive function can be impaired at BACs that are below the legal limit for driving in most countries.

Effects of alcohol and blood alcohol concentration limb on sexual risk-taking intentions

OBJECTIVE

Although there have been numerous investigations of alcohol's relationship to sexual risk taking, the vast majority of these studies have not examined whether the biphasic nature of alcohol intoxication differentially influences risky sexual decisions. Thus, a laboratory study was conducted to investigate the effects of alcohol consumption and blood alcohol concentration (BAC) limb on sexual risk-taking intentions.

METHOD

Participants (N = 150; 51.3% male) were randomly assigned to consume alcoholic drinks (target peak BAC = .08%) or nonalcoholic drinks and then completed a hypothetical sexual risk assessment involving an opposite-gender new partner while on either the ascending BAC limb or descending BAC limb.

RESULTS

Alcohol intoxication resulted in increased sexual risk-taking intentions indirectly through its influence on perceived intoxication and, subsequently, sexual arousal. An interaction of beverage condition and BAC limb condition indicated that alcohol's effects on perceived intoxication varied significantly by limb, with those on the ascending limb reporting greater perceived intoxication than those on the descending limb.

CONCLUSIONS

Findings suggest that future research and prevention efforts would be better informed through a more comprehensive consideration of BAC limb effects on sexual risk behaviors. Moreover, results indicate that prevention programs should address in-the-moment states, such as perceived intoxication and sexual arousal, in interventions targeting risky sexual decision-making processes.

Later That Night: Descending Alcohol Intoxication and Men's Sexual Arousal

Although men often have sex when intoxicated, basic questions remain about how alcohol affects erection. It may depend on whether blood alcohol level is ascending or descending and whether the situation calls for maximizing or suppressing erection. Objective. To evaluate whether descending intoxication affects erection when men are instructed to maximize or suppress arousal. Method. Seventy-eight heterosexual men were randomized to intoxication (descending from .08% vs. no alcohol) and arousal instruction (maximize vs. suppress) conditions. Response to erotica was examined using penile plethysmography. Results. Compared to similarly instructed sober men, intoxicated men instructed to maximize exhibited less erection yet reported greater effort to maximize. Interestingly, intoxicated men instructed to suppress exhibited more erection than those instructed to maximize. In general, however, observed effects were modest. Conclusions. Findings suggest there is no simple answer regarding how alcohol affects sexual arousal. Descending intoxication, depending on context, appears to affect erection capacity and control.

Selectively attending to natural scenes after alcohol consumption: An ERP analysis

Alcohol effects on cognitive, emotional and behavioral processes have been linked to an impairment of attention. Because attention operates at the level of specific cognitive subsystems, recent studies demonstrated alcohol effects in specific post-perceptual processes such as response selection and working memory. Measuring event-related potentials, the present study focused on perceptual processes by utilizing a categorization task where participants had to decide whether briefly presented images contained an animal or not. Findings demonstrate an early differential ERP activity for target compared to non-target images, which was reduced after alcohol intoxication. Thus, alcohol intoxication had deleterious effects at the perceptual level of processing considered to reflect the interaction of top-down (category-related) and bottom-up (stimulus-driven) processes. In addition, post-perceptual processes were also impaired by alcohol intoxication.

Memory encoding and retrieval on the ascending and descending limbs of the blood alcohol concentration curve

RATIONALE

Little is known about acute effects of alcohol on memory encoding and retrieval on different limbs (ascending and descending) of the blood alcohol concentration (BAC) curve.

OBJECTIVES

This extensive experiment was designed to examine alcohol's effects on memory encoding and retrieval throughout a protracted drinking episode.

METHODS

In a 9-h session, male participants consumed either alcohol (1 ml/kg) or placebo (n = 32/32) over a period of 90 min and learned various materials in different memory tasks before, during, and after consuming the drinks, while their BAC levels were monitored. A week later, in a similar session, they were tested on learned materials before, during, and after drinking. Mood was assessed throughout both sessions.

RESULTS

Alcohol impaired recall of words more than recognition, and cued recall most severely. Perceptual priming and picture recognition were not affected by alcohol. Alcohol impaired encoding in cued recall, recognition of completed word fragments, and free recall regardless of limb, but impaired retrieval in word recognition only during the ascending BAC. Alcohol increased negative mood on the descending limb during the first session, and on the ascending limb during the second session.

CONCLUSIONS

Under naturalistic drinking conditions, alcohol's effects on memory depend on task, memory process, and limb of the BAC curve. The differential effects of alcohol on retrieval during the ascending and descending limbs demonstrate the importance of examining the differential effects on the two limbs.

Influence of physical attractiveness and alcohol on men's perceptions of potential sexual partners and sexual behavior intentions

The current research presents the results of 2 related experimental studies designed to evaluate the influence of physical attractiveness and a moderate dose of alcohol on men's perceptions of potential sexual partners and sexual behavior intentions. Analyses revealed significant effects of physical attractiveness on partner perceptions and sexual behavior intentions. Although no main effects of alcohol were observed, alcohol differentially moderated the relations between perceived risk and sexual behavior intentions by limb of absorption. Results suggest that greater attention should be focused on identifying the specific physical characteristics of a potential sexual partner--beyond attractiveness--that influence perceptions of risk and intentions to engage in safer sex behaviors and highlight the importance of assessing limb of absorption in evaluating the complex association between alcohol and risky sexual behavior.

Alcohol-induced impairment of inhibitory mechanisms involved in visual search

The present study examined the effects of alcohol on the ability to perform a cued target detection task that measured inhibition of return (IOR). IOR is a reflexive inhibitory mechanism that delays attention from returning to a previously attended location and has been shown to increase the efficiency of a visual search. Ten social drinkers performed the task under 3 alcohol doses: 0.0 g/kg (placebo), 0.45 g/kg, and 0.65 g/kg. The results showed both active alcohol doses reduced the IOR effect by shortening its duration of influence. The reduced duration of IOR under alcohol suggests that repeated searches in previously explored locations might be more likely under the drug, thereby reducing search efficiency.

Alcohol affects executive cognitive functioning differentially on the ascending versus descending limb of the blood alcohol concentration curve

BACKGROUND

Executive cognitive functioning (ECF), a construct that includes cognitive abilities such as planning, abstract reasoning, and the capacity to govern self-directed behavior, has been recently researched as an antecedent to many forms of psychopathology and has been implicated in alcohol-related aggression. This study was designed to examine whether differential ECF impairments can be noted on the ascending versus the descending limbs of the blood alcohol concentration curve.

METHODS

Forty-one male university students participated in this study. Twenty-one subjects were given 1.32 ml of 95% alcohol per kilogram of body weight, mixed with orange juice, and the remaining 20 were given a placebo. Participants were randomly assigned to either an ascending or descending blood alcohol group and were tested on six tests of ECF on their assigned limb. Subjective mood data were also collected.

RESULTS

Intoxicated participants on both limbs demonstrated ECF impairment; the descending-limb group showed greater impairment than their ascending-limb counterparts. Intoxicated subjects were significantly more anxious at baseline than placebo subjects. The introduction of this covariate nullified any significant differences in subjective mood found on either limb of the blood alcohol concentration curve, but ECF impairments remained robust.

CONCLUSIONS

Our results support the conclusion that alcohol negatively affects cognitive performance and has a differential effect on the descending versus the ascending limb of the blood alcohol concentration curve. The latter finding may have important ramifications relating to the detrimental consequences of alcohol intoxication.

Profile of acute tolerance to three sedative anxiolytics

Acute tolerance, defined as a decreasing drug effect relative to drug-plasma levels (DPL) over a period of minutes to a few hours, is pronounced following single doses of diazepam or pentobarbital. Both of these lipid-soluble drugs produce an early peak behavioral impairment and subsequent rapid recovery component that is followed by a much slower blood-drug rise time. These pronounced early peak effects were not shared by alcohol, and contribute significantly to the lack of correlation between impairment and DPL.

Schedule-controlled operant behavior of rats during 1,1,1-trichloroethane inhalation: relationship to blood and brain solvent concentrations

The central nervous system is the principal target of 1,1,1-trichloroethane (TRI), and several studies of this volatile solvent have demonstrated effects on learned animal behaviors. There have been few attempts, however, to quantitatively relate such effects to blood or target organ (brain) solvent concentrations. Therefore, Sprague-Dawley rats trained to lever-press for evaporated milk on a variable interval 30-s reinforcement schedule were placed in an operant test cage and exposed to clean air for 20 min, followed by a single concentration of TRI vapor (500-5000 ppm) for 100 min. Additional rats were exposed to equivalent TRI concentrations for 10, 20, 40, 60, 80, or 100 min to determine blood and brain concentration vs. time profiles. Inhalation of 1000 ppm slightly increased operant response rates, whereas 2000, 3500, and 5000 ppm decreased operant response rates in a concentration- and time-dependent manner. Accumulation of TRI in blood and brain was rapid and concentration dependent, with the brain concentration roughly twice that of blood. Plots of blood and brain TRI concentrations against operant performance showed responding in excess of control rates at low concentrations, and decreasing response rates as concentrations increased. Linear regression analyses indicated that blood and brain concentrations, as well as measures of time integrals of internal dose, were strongly correlated with operant performance. Neurobehavioral toxicity in laboratory animals, as measured by changes in operant performance, can therefore be quantitatively related to internal measures of TRI exposure to enhance its predictive value for human risk assessment.

The relation between alcohol and aggression: an integrated biopsychosocial conceptualization

The relation between acute alcohol consumption and aggressive behavior is a complex phenomenon that has been studied from a variety of different disciplines. This article reviews findings from both survey and experimental research. The influence of both situational and individual difference variables on the alcohol-aggression relation is discussed and the strengths and weaknesses of various methodological approaches are highlighted. Current theoretical perspectives of the alcohol-aggression relation are reviewed. An integrated heuristic framework of the alcohol-aggression relation also is outlined. This conceptualization involves both distal and proximal risk factors for problems with alcohol and violence, which include biological, psychological, interpersonal, and contextual influences. Research and treatment implications of this framework are also discussed. It is recommended that researchers attempt to measure variables from a variety of domains in order to obtain a better understanding of this complex phenomenon. Furthermore, it is emphasized that there is a clear need to further implement and assess primary and secondary prevention efforts and to design integrated and flexible approaches for individuals with alcohol and violence problems.

The effect of lorazepam on long-term verbal recall in heavy and light social drinkers

Two experiments investigated long-term verbal memory performance in groups of 20-year-old heavy (HSDs) and light social drinkers (LSDs), in the presence and absence of a pharmacological challenge (lorazepam 2 mg). In Experiment 1 (n = 13), a verbal learning task was presented visually and it was found that lorazepam significantly impaired delayed verbal recall performance in both groups. Experiment 2 (n = 14) assessed the effect of presenting the verbal learning task in the auditory compared to the visual modality. Both groups' performance on the delayed trials of the visually presented task was reduced in the lorazepam treatment. However, in the auditory presented task, lorazepam reduced 30-min delayed recall performance in the HSDs but not in the LSDs. The differential effect of lorazepam on HSDs compared to LSDs on delayed recall performance when material is presented in the auditory modality may suggest that frequent heavy social drinking results in changes in CNS functioning.

Acute alcohol tolerance in social drinkers: changes in subjective effects dependent on the alcohol dose and prior alcohol experience

Using subjective ratings of the degree of alcohol intoxication, the interaction between the drinking history of the subjects, the alcohol dose, and acute alcohol tolerance were examined in light and moderate alcohol consumers (N = 10). Both groups of subjects were tested with doses of alcohol corresponding to 0.5 and 1.0 g/kg. Dose order was random and tests were carried out with an interval of 1 week. Reports of the subjects' previous experience with these doses of alcohol indicated that the moderate consumers ingested the lower (but not the higher) of the doses quite regularly, whereas light consumers were rather inexperienced with both of the doses. Comparison of blood alcohol concentrations as measured by breath and blood analysis yielded slightly different results, the concentrations being significantly higher as measured by breath analysis. This result was mainly associated with the initial phases, where this difference was greatest. Acute tolerance was assessed by comparing the ratings at equal concentrations of alcohol on the ascending and the descending limbs of the alcohol concentration curve. Due to the lag in the measurements of breath and blood alcohol concentrations, the outcome of the evaluations of acute tolerance was also influenced by whether breath or blood alcohol concentrations were used to obtain similar concentrations in both phases. Results based on the breath alcohol concentrations showed that in light alcohol consumers, acute tolerance was demonstrated for both of the doses. In moderate alcohol consumers only the higher of the doses produced evidence for acute tolerance. However, if comparisons are based on blood alcohol concentrations, moderate alcohol consumers also show an apparent acute tolerance for the lower of the doses tested. The present results clearly demonstrate the complexity of the acute tolerance phenomenon, and emphasize the fact that the results are dependent on the dose of alcohol, the subjects' prior experience with alcohol as well as the procedure used for measuring alcohol concentration.

Alcohol pharmacodynamics in young-elderly adults contrasted with young and middle-aged subjects

Effects of aging on ethyl alcohol (EtOH) pharmacodynamics were examined over progressive dosing schedules (0.4, 0.6, 0.8, 1.0 g/kg) in groups of young (25.0 +/- 2.9 years), middle-aged (41.1 +/- 6.6 years), and young-elderly adults (60.9 +/- 2.6 years) using three computerized cognitive-neuromotor tasks: digit-symbol substitution (DSS), keypad reaction time (KRT), and subcritical tracking (SCT). Hysteresis curves of performance impairment (adjusted for pre-drug baseline) as a function of blood alcohol concentration (BAC) were examined for time-course effects, and regression analyses were performed to assess the contribution of age beyond that accounted for by BAC. Results reflected differences in the patterning but not magnitude of impairment for elderly subjects, with earlier decrements and more rapid acute tolerance observed for DSS, in conjunction with less pharmacodynamic sensitivity for SCT. Regression analyses furthermore indicated that age and impairment were negatively related, arguing against synergistic intoxication effects as a function of aging. Analyses specifically comparing performance at baseline versus legally intoxicating BACs (> 1.0 mg/ml) likewise reflected a lack of interactive effects involving the elderly. Elderly subjects nevertheless exhibited significantly lower baseline performance for DSS and KRT than young subjects and achieved higher BACs with equivalent doses. These latter findings support the exercise of caution by elderly individuals consuming EtOH prior to engaging in neuromotor pursuits such as driving.

Effects of ethanol on psychomotor performance under steady-state conditions

Ethanol was administered to eight male volunteers using an oral loading dose followed by repeated small oral doses to achieve approximate steady-state drug concentrations in a double-blind placebo controlled cross over design. Ethanol or placebo were administered over a 5-h period in two sessions at least 7 days apart. The effects of ethanol were assessed using a short battery of psychomotor tests and visual analogue scales which was administered repeatedly during the steady-state period, and a long battery administered once before and once during the steady-state period. The concentrations of ethanol in plasma and breath were determined at 20-min intervals. Mean plasma concentrations of 94 mg/100 ml were obtained. Ethanol produced a clear impairment to psychomotor performance, with a 41% increase in body sway, a 61% increase in errors on a maze task, a 6.5% reduction in digit-symbol substitution and an 8% slowing in tapping. Subjective feelings of drunkenness and sedation were noted. No measure showed evidence for acute tolerance, as assessed by comparison of the slopes fitted to the performance measures in the short battery.

Impairment and recovery under repeated doses of alcohol: effects of response-outcomes

This research examined the behavioral effect of alcohol during rising and declining blood alcohol concentrations (BACs) when the dose was repeated three times (mean peak BAC = 78 mg/100 ml). A total of 36 male social drinkers learned a complex psychomotor task and subsequently performed it at intervals after alcohol was received. Subjects performed under one of two conditions: an experimental (E) treatment associated drug-compensatory (nonimpaired) task performance with a positively reinforcing outcome or a control (C) treatment associated no environmental consequence with performance. E treatment diminished impairment at all positions on the BAC curve and carried over to result in progressively less impairment when the dose was repeated. In contrast, C treatment tended to increase impairment around the BAC curve with repeated doses. The rate of recovery during declining BACs remained stable across sessions and was not altered by the treatments. The results imply that impairment under a dose of alcohol is governed by two processes: response-outcome associations that determine the amount of impairment displayed under a dose and some adaptive process that determines the rate of recovery with time during exposure to a dose.

Daily dose of ethanol and the development and decay of acute and chronic tolerance and physical dependence in rats

Using behavioral and physiological measures, we compared the rates of development and decay of acute and chronic tolerance to ethanol (ET) and the severity of the withdrawal syndrome. Male rats were treated with 6, 9, or 12 g/kg/day ET or equicaloric dextrin maltose, delivered intragastrically. Although treatment duration varied, the total dose of ET was kept constant at 162 g/kg/rat for the three groups. The effects of a cumulative test dose of ET or equicaloric dextrin maltose, after exposure to a total of 0, 42, 83, 126, and 162 g/kg ET, and at 3, 5, and 7 days after termination of the chronic treatments, were evaluated on rectal temperature, dowel performance, and tail-flick and startle responses. After the initial five tolerance tests, chronic treatments were discontinued and rats were tested in a modified open-field apparatus and for their startle response to an auditory stimulus at 8, 12, 16, 20, 32, and 40 h later. With all measures, little tolerance developed in the 6-g/kg/day group. On the other hand, development of chronic tolerance was fastest in rats treated with the 12-g/kg/dose of ET. Chronic tolerance did not develop to ET's depressant effect on the startle response. Acute tolerance declined with chronicity of treatment in animals given the largest daily dose of ET. During withdrawal, and in contrast to the dextrin maltose-treated animals, there was impairment in all measures taken during the modified open-field test and hypersensitivity of the startle response for all three chronic ET-treated animals. Greatest behavioral impairment occurred in animals treated with 12 g/kg/day, and some impairment was still evident 40 h after the last dose of ET. Thus, the severity of the withdrawal syndrome was greatest in the group displaying the most acute and chronic tolerance.

Estimation of blood alcohol concentrations in young male drinkers

This research examined individual differences in the ability to self-monitor the effects of alcohol. Thirty-nine male subjects consumed 0.75 ml/kg alcohol and estimated their blood alcohol concentrations (BACs) at peak BAC and on the ascending and descending limbs of the blood alcohol curve. Family history of alcohol dependence did not affect the accuracy of estimation of BACs. Subjects who reported lower levels of subjective intoxication underestimated their BACs more than did subjects who reported higher levels of subjective intoxication. Subjects with less behavioral impairment underestimated their BACs more than subjects with greater behavioral impairment on the ascending limb of the blood alcohol curve. Accuracy was better on the ascending limb compared with peak BAC and the descending limb, and accuracy became worse over time on the descending limb. It appears that cues to the effects of alcohol rapidly become unavailable on the descending limb, which may contribute to decisions concerning further alcohol consumption and driving after drinking.

Association of self-reported injury and alcohol consumption in medical outpatients

OBJECTIVE

This study was designed to examine the association between minor injury and level of alcohol consumption among adult outpatients.

DESIGN

Self-administered survey of alcohol use and level of injury in prior month.

SETTING

Adult outpatients attending a university-based general internal medicine private practice.

PATIENTS/PARTICIPANTS

During a four-month period, 1,011 patients aged 18-65 years were asked to complete questionnaires while waiting to see a physician. The 791 who completed all forms appropriately are included in this study.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The total number of drinks and the total number of injuries reported during the preceding month were calculated. Nondrinkers reported an average of 0.51 (SD = 1.18) injuries in the prior month; and drinkers, 0.92 (SD = 1.70) injuries. Minor injuries were reported more frequently by heavier alcohol consumers only among younger patients (RR = 1.88). There was no association between reported injury and alcohol consumption among patients over 50 years of age (RR = 0.90).

CONCLUSIONS

Minor injury is associated with heavier alcohol consumption in younger patients attending a general medical practice, but not among older patients. Further research is needed to establish a causal relationship between alcohol drinking and minor injury.

The pharmacodynamics of ethanol: effects on performance and judgment

The objective and subjective effects produced by increasing and decreasing ethanol concentrations were studied in healthy volunteers on three separate occasions. A randomized, double-blind, placebo-controlled, four-way crossover study was used to determine whether there is any disparity between the time course of blood ethanol concentration and its effects on either objective test performance or self rated impairment. On each study day the subjects received one of four treatments consisting of either placebo or sufficient alcohol to achieve peak estimated blood alcohol concentration (Est.BAC) of 0.07 gm/dL, 0.1 gm/dL or 0.14 gm/dL. Est.BAC determined from breath alcohol concentrations were measured 20 minutes after each "dose" until peak Est.BAC was achieved, then 1, 2, 3.5, and 4.5 hours after peak Est.BAC. Digit symbol substitution (DSS), simulated driving reaction time (SDRT), choice reaction time (CRT) and self assessment of impairment (SRI) were measured simultaneously with Est.BAC. Changes in objective performance test scores were well correlated with Est.BAC (r2 = 0.60 P less than .01). Maximum impairment in test performance occurred at the same time as peak Est.BAC. Threshold Est.BAC needed to produce changes in objective test scores greater than placebo were 0.06 +/- 0.01 for DSS, 0.04 +/- 0.01 for SDRT, and 0.04 +/- 0.02 for CRT. There was no evidence of between dose or within dose tolerance to the effects produced by various Est.BAC on any of these performance tests. Subjects' self rated degrees of impairment at various Est.BAC were influenced by whether alcohol concentrations were rising or falling. Subjective impairment ratings were greater while alcohol concentrations were increasing compared to the same Est.BAC occurring during falling alcohol concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of kinetic-dynamic interactions in the evaluation of drugs

Deterred by the complexity of the mathematics, pharmacologists and clinical pharmacologists have only recently appreciated the usefulness of pharmacokinetics in drug development. Now unfortunately, although the vernacular of the science is known, often the meaning behind the words is lost. It is often assumed that drug levels are linearly related to drug action. Frequently they are not. This review shows, with reference to psychotropic drugs, how, in simple terms, it is possible to relate pharmacokinetics with pharmacodynamics, and how such relationships may provide a greater insight into drug activity and enhance drug development. Assuming that an equilibrium exists between the drug in plasma levels, and at the site of action, the same Michaelis-Menten equations used to relate effect to drug receptor binding can be used for drug level-dynamic interactions. A number of these relationships have been published and are discussed in terms of their derivation and their limitations. The graphical and computerised methods to create complete Emax curves are described and how the parameters of maximal effect, potency, variability and slope can be measured. When the drug is not in equilibrium with its site of action, hysteresis occurs and drug levels are out of phase with activity. Anticlockwise hysteresis, that is, activity increasing with time for a given drug level, can be caused by uptake into an active site, active metabolites, cascade activity, and sensitisation whilst clockwise hysteresis, in which activity decreases with time, can be caused by tolerance, active antagonistic metabolites, learning effects and feedback regulation. Attempts to relate simultaneously kinetics and dynamics by Link models can be difficult and not always necessary. It is assumed in therapeutic drug monitoring that individuals will show the same response for a given drug level. On the contrary, differences in individual subject sensitivity to drugs measured by kinetic-dynamic relationships may provide a greater understanding of the disease itself.

The blood alcohol curve as a function of time and type of beverage: methodological considerations

Six male subjects came to the laboratory on three different occasions and drank either spirits, wine, or beer. The spirits drink contained 1.0 ml of pure alcohol/kg body wt. and the other two drinks were 20% larger. The blood alcohol curve was monitored every 15 min. The mean peak level was roughly the same for the three types of beverages although the peak was reached later for wine and beer. For spirits and beer the curve dropped off smoothly after the peak was reached while for wine the peak level was maintained for about 60 min. Individual curves varied greatly for all three beverage types. The results are discussed in terms of methodological complications when doing experimental research in the laboratory.

Effect of raphe lesions on the development of acute tolerance to ethanol and pentobarbital

The effect of electrolytic lesions in the median and dorsal raphe nuclei was tested on acute tolerance development to ethanol and pentobarbital in the rat, as measured by motor impairment on the moving belt test. Acute tolerance to ethanol (1.7 g/kg, IP) or pentobarbital (17.5 mg/kg, IP) was monitored at 12.5, 25, or 50 min in separate subgroups tested only once each. One week of recovery was allowed between ethanol and pentobarbital tests. Median raphe lesions delayed the development of acute tolerance, whereas dorsal raphe lesions produced a negligible effect. These results were seen with both ethanol and pentobarbital. The mesolimbic 5-HT pathway from the median raphe nucleus is important in the development of acute tolerance to ethanol and pentobarbital, as was shown to be the case previously for chronic tolerance.

Neurobehavioural effects of occupational exposure to organic solvents among construction painters

A cross sectional study of 101 construction painters was performed to investigate the relation between exposure to mixed organic solvents and changes in central nervous system function. Solvent exposure was estimated using questionnaire data to derive an exposure index (a measure of intensity of exposure) and to estimate the duration and frequency of exposure. Adverse effects on the central nervous system were assessed by self reported questionnaires and eight tests of a computer administered neurobehavioural evaluation system. Factor analysis of both measures of effect yielded factors both biologically plausible and in agreement with other empirical evidence. A consistent positive association was observed between most measures of exposure and the occurrence of neurotoxic symptoms, notably dizziness, nausea, fatigue, problems with arm strength, and feelings of getting "high" from chemicals at work. Associations with exposure were found with the neurobehavioural evaluation system tests of symbol digit substitution and digit span; however, no consistent pattern of effect on neurobehavioural function was observed. This pattern of the occurrence of neurotoxic symptoms without clear evidence of function deficit is consistent with the type 1 toxic central nervous system disorder as classified by the World Health Organisation.

Use of regression residuals to quantify individual differences in acute sensitivity and tolerance to alcohol

Due to the problem of correlation of errors inherent in the difference or ratio scores typically used to quantify individual differences in acute sensitivity and tolerance to alcohol, it is recommended that residual scores from regression analyses be used instead for such quantification. Conceptualizations of acute sensitivity and tolerance and problems with the reliability of change scores are also discussed.

Frustration as an important determinant of alcohol-related aggression

An experimental study was performed to investigate the relationship between alcohol, frustration, and aggression. The hypothesis tested stated an increase in aggression as a result of alcohol only under frustrative conditions. Two alcohol doses and a placebo dose were tested in a modified “shock-machine” procedure. Human males were frustrated by a bogus partner when thwarted in winning a sum of money, and aggression was measured by intensity and duration of electric shocks given to the bogus partner. Subjects were supervising their partners on a visual scan test demanding concentration and were required to deliver shocks for incorrect responses. The results show no effects of alcohol under nonfrustrative conditions but increased aggression for the intensity measure for the high-alcohol-dose group under frustrative conditions compared to the placebo group and the low-alcohol-dose group. The hypothesis was supported and results were discussed in terms of a shift in attentional processes under alcohol to only salient features of a situation thereby taking on increased subjective significance.

Cognitive and electrophysiologic parameters during ascending and descending limbs of the blood alcohol curve

This study examined the effects of acute alcohol ingestion and prior success or failure upon cognitive performance of 40 healthy, non-alcoholic subjects, during both the ascending and descending limbs of the blood alcohol curve. Measures of physiological arousal were made with frontal/laryngeal electromyographic and skin conductance response level parameters. Major findings were: (1) cognitive performance was impaired by alcohol ingestion; (2) autonomic arousal was significantly greater after alcohol than after placebo; (3) number and amplitude of skin response were greater on the ascending than on the descending limb; (4) the anticipated effects of failure on cognitive performance were ameliorated by alcohol; and (5) differential effects of alcohol on the psychophysiological parameters were demonstrated.

Alcohol use and cognitive loss among employed men and women

A representative sample of 1,367 employed men and women in Detroit responded to questions about their drinking practices and then completed a cognitive test which measures abstraction abilities. Abstraction, tested while respondents were sober, decreased significantly as reported quantity of alcohol usually consumed per drinking occasion increased. (Am J Public Health 1983; 73:521-526.)

Relationships between several pharmacokinetic parameters and psychometric indices of subjective effects of delta 9-tetrahydrocannabinol in man

This study explored the relationships in man between various pharmacological effect of delta 9-tetrahydrocannabinol (THC), plasma THC concentration, and pharmacokinetic parameters of THC. Three male and three female experienced marihuana users smoked two standard marihuana cigarettes. The relationships between heart rate, subjective "high" rating, Linear Mood Scale factors, and plasma THC concentration were assessed. Significant correlations were observed between various Linear Mood Scale factors and pharmacokinetic parameters reflecting the magnitude of drug intake and the degree of temporal dissociation between the time courses of plasma THC concentration and pharmacological effects (tachycardiac effect, "high"). In particular, the disturbed/weird and sensitive/aware mood factors correlated positively with pharmacokinetic measures of drug intake and time lag to effect. A more reliable index of intoxication with THC may be provided by the global subjective "high" rating, rather than other ratings more specific for particular moods.

Alcohol's effects on human emotions: a review of the stimulation/depression hypothesis

Recent hypotheses hold that acute alcohol consumption sequentially stimulates and then depresses (stimulation/depression) the drinker's emotional state as well as other physiological and non-mood-related behavioral functions. This paper traces the development of the stimulation/depression hypothesis as applied to human emotions and critically evaluates investigations of alcohol's acute emotional effects in order to assess its validity. Although some evidence suggests and elatant (i.e., stimulant) effect of alcohol at moderate intoxication levels, particularly on the rising limb of the blood alcohol curve, it is concluded that because of methodological inadequacies in the relevant experimental literature, the stimulation/depression hypothesis as applied to emotions remains largely untested. Conceptual and methodological refinements necessary for testing the hypothesis are discussed, and potentially important nonpharmacological factors that may also influence postconsumption mood changes are identified.