Target Blood Alcohol Concentration Research Articles

Acetaldehyde-mediated increase in glutamatergic and N-acetylaspartate neurometabolite levels in the midcingulate cortex of ALDH2*1/*2 heterozygous young adults.

To elucidate the neurobiology underlying alcohol's effect on the human brain, we examined the acute effects of moderate alcohol administration on levels of glutamatergic neurometabolites and N-acetylaspartate, an amino acid found in neurons, may reflect disordered neuronal integrity. Eighteen healthy Japanese participants (7 males/11 females) aged 20-30 years who were heterozygous for an inactive allele of acetaldehyde dehydrogenase-2 (ALDH/*1/*2) were included. Participants underwent an intravenous alcohol infusion using the clamp method at a target blood alcohol concentration (BAC) of 0.50 mg/mL for 90 min within a range of ±0.05 mg/mL. We examined glutamate + glutamine (Glx) and N-acetylaspartate N-acetylaspartylglutamate (NAA) levels in the midcingulate cortex (MCC) using 3 T 1 H-MRS PRESS at baseline, 90 min, and 180 min (i.e., 90 min after alcohol infusion was finished). A two-way repeated-measures analysis of variance was used to assess longitudinal changes in Glx and NAA levels, with time and sex as within- and between-subject factors, respectively. Pearson's correlation coefficients were calculated among neurometabolite levels and BAC or blood acetaldehyde concentration (BAAC). Both Glx (F(2,32) = 8.15, p = 0.004, η2 = 0.15) and NAA (F(2,32) = 5.01, p = 0.04, η2 = 0.07) levels were increased after alcohol injection. There were no sex or time × sex interaction effects observed. NAA levels were positively correlated with BAAC at 90 min (r(13) = 0.77, p = 0.01). There were no associations between neurometabolite levels and BAC. Both Glx and NAA levels in the MCC increased in response to the administration of moderate concentrations of alcohol. Given positive associations between NAA levels and BAAC and the hypothetical glutamate release via dopamine pathways, the effects of drinking on the MCC in the acute phase may be ascribed to acetaldehyde metabolized from alcohol.

Change in brain asymmetry reflects level of acute alcohol intoxication and impacts on inhibitory control

Alcohol is one of the most commonly used substances and frequently abused, yet little is known about the neural underpinnings driving variability in inhibitory control performance after ingesting alcohol. This study was a single-blind, placebo-controlled, randomized design with participants (N = 48 healthy, social drinkers) completing three study visits. At each visit participants received one of three alcohol doses; namely, a placebo dose [equivalent Blood Alcohol Concentration (BAC) = 0.00%], a low dose of alcohol (target BAC = 0.04%), or a moderate dose of alcohol (target BAC = 0.08%). To measure inhibitory control, participants completed a Go/No-go task paradigm twice during each study visit, once immediately before dosing and once after, while their brain activity was measured with time-domain functional near-infrared spectroscopy (TD-fNIRS). BAC and subjective effects of alcohol were also assessed. We report decreased behavioral performance for the moderate dose of alcohol, but not the low or placebo doses. We observed right lateralized inhibitory prefrontal activity during go-no-go blocks, consistent with prior literature. Using standard and novel metrics of lateralization, we were able to significantly differentiate between all doses. Lastly, we demonstrate that these metrics are not only related to behavioral performance during inhibitory control, but also provide complementary information to the legal gold standard of intoxication (i.e. BAC).

Association of cerebellar and pre-motor cortex gray matter density with subjective intoxication and subjective response following acute alcohol intake

Acute alcohol intake produces subjective intoxication (SI) and response (SR; e.g., valanced stimulation and sedation), which has important implications for alcohol-related risk. Individuals who experience less SI may be more likely to engage in risky behaviors while drinking. Gray matter morphometry in brain regions underlying cognitive and affective processes may help to inform individual differences in subjective intoxication and response. The subjective effects of alcohol vary between limbs of the blood alcohol concentration (BAC) curve (i.e., whether BAC is rising or falling; acute tolerance). We examined the relationship between gray matter density (GMD) and SI/SR as a function of BAC limb. Healthy social drinkers (N = 89; 55 women) completed an alcohol challenge paradigm (target BAC = 0.08 g/dL) and structural magnetic resonance imaging (MRI). Participants completed measures of SR and SI on ascending and descending BAC limbs. Association between GMD and SI/SR on each limb were assessed using whole-brain, voxel-wise general linear models. GMD estimates were extracted from significant clusters. Differences in association of GMD and SI/SR between limbs were assessed using hierarchical regression. Significant associations of SI with GMD on the ascending limb were observed in the cerebellum. A significant association between SR and GMD on the descending limb were observed in the pre-motor cortex (BA6) and cerebellum. We identified common and unique associations among cerebellum and pre-central gyrus structures with SI and SR between BAC limbs. Functional imaging studies may further clarify unique dimensions of subjective alcohol effects linked to the observed structural associations.

The influence of alcohol and automation on drivers’ visual behavior during test track driving

BackgroundDriving under the influence of alcohol severely increases crash risk. Impairment detection during driving is therefore key to improve traffic safety. However, future detection systems need to capture impairment for more reasons than alcohol intoxication and must also function in all driving modes (manual, assisted, autonomous). Driver Monitoring Systems (DMS) are promising candidates for such broader impairment detection. MethodA test track study investigated the effects of alcohol intoxication on drivers’ visual behavior both when just driving and when engaged in a non-driving related task. Twenty-six participants performed two drives: 1) sober baseline, 2) with a target blood alcohol concentration of 0.1%. The participants drove in either manual, assisted, or autonomous drive (AD) mode. ResultsIntoxication influenced glance behavior in all driving modes. It was most evident during visually demanding non-driving related tasks where it resulted in longer single and total off-path glance durations. Additionally, when just driving in manual mode, almost one third of the drivers displayed gaze concentration to the forward roadway when intoxicated. For sober driving, the difference in visual behavior between manual and assisted mode were moderate. In contrast, there was a huge shift towards longer off-path glances, lower percent road center, and lower off-path glance frequency in AD mode. ConclusionsIntoxication clearly affects drivers’ on/off road glance behavior. However, it is necessary to account for both driving mode and engagement in non-driving related tasks to reliably distinguish sober from drunk driving. Glance metrics has the potential to serve as a sub-set of indicators for a broader DMS-based detection of impaired driving, which can inform the decisions on when to activate in-vehicle countermeasures.

Can PEth be Detected with a Cutoff of 20ng/mL after Single Alcohol Consumption?

Phosphatidylethanol (PEth) can be determined in capillary blood collected as dried blood spots (DBS) and is a promising direct alcohol biomarker for the determination of drinking habits. Its use for abstinence monitoring needs to be evaluated. Studies with patients undergoing alcohol withdrawal have shown that the elimination of PEth can take up to 2months. For the determination of PEth 16:0/18:1, a cutoff of 20 ng/mL has been agreed upon in the major US laboratories. However, it is not yet clear what minimum blood alcohol concentrations (BACs) have to be achieved by a single drinking episode to result in PEth concentrations above this cutoff after previous long-term abstinence. To determine whether low drinking amounts can result in a positive PEth concentration above 20 ng/mL, we recruited 12 participants ('social' drinkers). After 4weeks of abstinence, alcohol was consumed at two separate drinking events with target BACs of 0.5 and 0.3 g/kg, resulting in maximum BACs in the ranges of 0.30-0.63 g/kg and 0.10-0.28 g/kg, respectively. Capillary blood was collected at different time points of the drinking experiment, and PEth was extracted from DBS and analyzed by liquid chromatography-tandem mass spectrometry. Despite drinking doses up to 0.58 g ethanol per kg body weight and reaching BACs of up to 0.63 g/kg, PEth 16:0/18:1 and PEth 16:0/18:2 could not be detected at or above the 20 ng/mL cutoff in any participant at any time after the drinking events. We conclude that after long-term abstinence the cutoff of 20 ng/mL for single alcohol consumption leading to BACs up to 0.63 g/kg is not exceeded.

Optimization of DBS-self sampling for PEth in a drinking experiment with standard DBS cards and with a new design of volumetric DBS card

Due to insufficient sample quality when using capillary-blood self-sampling in a drinking experiment for phosphatidyl ethanol (PEth) determination, we implemented an additional quality criterion for DBS and tested a new paper-based DBS card. We finally present results of PEth concentrations in capillary blood in a drinking study with blood alcohol concentrations (BAC) of up to 0.75 g/kg. We recently reported on a drinking experiment with BACs up to 0.5 g/kg, after long-term abstinence, where PEth was not detectable in any DBS sample with a cut-off of 20 ng/mL. Therefore, we adjusted the target BAC in further drinking experiments up to 0.75 g/kg. DBS sampling has been described as “easy”. When using commercial DBS cards for self-sampling with an imprinted circle, we found that some subjects had problems placing a full-sized droplet on the DBS card in an appropriate way. Instead, there some touched the card surface with the finger once a small drop had formed on the fingertip, and filled the printed circle on the card by repeatedly touching the card's surface. Thus, the blood is not sucked vertically through the entire card, which results in the sample not being quantitatively evaluable. We have introduced an important quality criterion for evaluable DBS cards: results can only be valid if the blood-soaked area on the front and on the back of the DBS-card is sufficient for extraction. This can be seen by the size of the extraction circle imprinted by the autosampler extraction tool (CAMAG, using a 4 mm diameter) after extraction on both sides. In practice, this means that the blood-penetrated circular area on the front and on the back of the card must have a minimum diameter of 6 mm if an extraction tool with 4 mm diameter is used. In order to optimise DBS self-collection, a newly designed card with a paper comb with four teeth per card (DBSv, Protzek, Lörrach, Germany) was evaluated – in parallel to the use of standard DBS cards. A preanalytical criterion for the validity of DBS self-sampling by a standard filter-paper DBS card (without the use of a volumetric device) was defined – with respect to full penetration of the DBS-card from the front to the back by the collected blood. In the drinking experiment, PEth was found positive (above the cut-off of 20 ng/mL) after a single drinking event with target BACs of up to 0.75 g/kg. PEth concentrations reached up to 119 ng/mL PEth 16:0/18:1 (starting from PEth negative before start of drinking) and declined to below 40 ng/mL within five days. Although four weeks of abstinence from ethanol were required prior to the first drinking event, half of the volunteers still had positive PEth values (above 20 ng/mL) at the time of the drinking event and had to be eliminated from the study. Furthermore, the new DBSv card (Protzek, Lörrach, Germany) allowed a volumetric collection of approx. 20 μL blood per tooth, circumventing the problem, that not enough blood is collected per spot. We could assure the quality of DBS self-sampling by an additional quality requirement as well as by new volumetric DBSv cards. In the drinking experiment, PEth-concentrations above 20 ng/mL were obtained by single drinking up to a BAC of 0.75 g/kg.

Influence of alcohol and acetaldehyde on cognitive function: findings from an alcohol clamp study in healthy young adults.

To investigate the acute effects of intravenous alcohol and its metabolite acetaldehyde on cognitive function in healthy individuals. Experimental pre-test/post-test design. Kurihama Medical and Addiction Center, Japan. A total of 298 healthy Japanese people age 20 to 24 years. Participants underwent an intravenous alcohol infusion with a target blood alcohol concentration (BAC) of 0.50 mg/mL for 180 minutes. Participants completed the continuous performance test (CPT) for sustained attention, the paced auditory serial addition test (PASAT) for working memory, and the reaction time test (RTT) for speed/accuracy, along with the blood test for BAC and blood acetaldehyde concentration (BAAC) at baseline, 60 and 180 minutes. Although the target BAC was maintained during the infusion, BAAC peaked at 30 minutes and then gradually declined (η2 = 0.18, P < 0.01). The CPT scores worsened, and the changes between 0 and 60 minutes were correlated with BAAC (correct detection, η2 = 0.09, P < 0.01; r = -0.34, P < 0.01; omission errors, η2 = 0.08, P < 0.01; r = 0.34, P < 0.01). PASAT scores improved through 180 minutes, whereas the changes between 0 and 60 minutes were negatively correlated with BAAC (task one, η2 = 0.02, P < 0.01; r = -0.25, P < 0.01; task two, η2 = 0.03, P < 0.01; r = -0.28, P < 0.01). Although RTTs worsened, they were not associated with BAC or BAAC. None of these comparisons maintained the time effect after controlling for body height. Acetaldehyde exposure following acute intravenous alcohol appears to have a negative impact on sustained attention and working memory, whereas there seems to be only a minor effect of moderate alcohol concentration on speed and accuracy.

Acute Tolerance to the Analgesic Effects of Alcohol

The goal of this study was to determine whether the acute analgesic effects of alcohol intake are moderated by acute alcohol tolerance, characterized by differing subjective and neurobehavioral effects of a given blood alcohol concentration (BAC) depending on whether BAC is rising or falling. Twenty-nine healthy drinkers (20 women) completed two laboratory sessions in which they consumed a study beverage: active alcohol (target BAC= .08 g/dl) and placebo. Acute alcohol tolerance was assessed by examining the main and interactive effects of beverage condition and assessment limb (ascending vs. descending) on quantitative sensory testing measures collected using slowly ramping heat stimuli and perceived relief ratings at comparable breath alcohol concentrations on the ascending and descending limbs. BAC limb moderated the effect of condition on pain threshold, such that the threshold was significantly elevated in the alcohol condition on the ascending limb. The alcohol condition produced greater ratings of perceived pain relief than the placebo condition, and pain relief ratings were greater on the ascending versus descending limb of the BAC curve. Alcohol intake did not significantly affect pain tolerance or aftersensation ratings on either BAC limb. This study provides initial experimental evidence that alcohol's analgesic and pain-relieving effects are subject to acute tolerance following acute alcohol intake. These findings suggest that self-medicating pain via alcohol intake may be associated with high-risk drinking topography, increasing the risk for alcohol-related consequences. Further research is needed to determine if these effects extend to the context of clinical and chronic pain.

Contextual influences on subjective alcohol response.

Prior research demonstrates contextual influences on drug responses in both animals and humans, although studies in humans typically focus on only one aspect of context (e.g., social) and examine a limited range of subjective experiences. The current study sought to address these limitations by examining the impact of both social and physical context on the full range of subjective alcohol effects. The sample included 448 young adult social drinkers (57% male, 66.5% White) randomly assigned to consume alcohol (target blood alcohol concentration of .08 g%) or placebo in 1 of 4 contexts (solitary lab, group lab, solitary bar, group bar). Results indicated that high arousal positive (HAP) effects of alcohol (e.g., talkative, lively) were stronger in nonbar relative to bar contexts and that low arousal positive (LAP) effects (e.g., relaxed, calm) were only present in the group lab context. There were also main effects of social context such that high arousal effects (both positive and negative) were stronger in group contexts, regardless of beverage condition. These findings highlight the importance of considering context when examining alcohol effects. Studies designed to isolate pharmacological HAP effects may benefit from a nonbar setting, and studies of LAP effects might be most effective in a simulated living room or home environment, although future studies are needed to directly address this possibility. Further, studies with an explicit focus on expectancies or that need strong control for expectancies might benefit from a group context, particularly when studying high arousal effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

A multimodal, longitudinal investigation of alcohol's emotional rewards and drinking over time in young adults.

Theories of alcohol use disorder (AUD) have long suggested that alcohol's emotional rewards play a key role in reinforcing problematic drinking. Studies employing survey methods, in which participants recall and aggregate their experiences with alcohol in a single questionnaire, indicate that self-reported expectancies and motivations surrounding alcohol's emotional rewards predict problematic drinking trajectories over time. The current study is the first to combine laboratory alcohol-administration, ambulatory methods, and longitudinal follow-ups to assess whether alcohol's ability to enhance positive mood and reduce negative mood predicts later drinking problems. Sixty young heavy social drinkers (50% female) participated in laboratory-based alcohol-administration, attending both alcohol (target blood alcohol concentration [BAC] .08%) and no-alcohol laboratory sessions. Forty-eight of these participants also wore transdermal alcohol monitors and completed mood surveys outside the laboratory for 7 days. Participants reported on their drinking at 18-month follow-up (90% compliance). Controlling for baseline drinking, greater negative mood reduction from alcohol at baseline predicted more drinking problems at follow-up, an effect that emerged as consistent across methods capturing alcohol's emotional rewards in the laboratory, b = -.24, p = .02, as well as via ambulatory methods, b = -3.14, p = .01. Greater positive mood enhancement from alcohol, captured via laboratory methods, also predicted drinking problems, b = .16, p = .03, and binge drinking, b = 3.22, p = .02, at follow-up. Models examining drinking frequency/quantity were nonsignificant. Results provide support for emotional reward as a potential factor in the development of problematic drinking. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Influence of alcohol consumption on blood coagulation in rotational thromboelastometry (ROTEM): an in-vivo study.

BackgroundTwenty-five to 85% of trauma patients are under the influence of alcohol in addition to experiencing injury-related coagulation impairment. Viscoelastic point-of-care tests (thrombelastography [TEG], rotational thromboelastometry [ROTEM]) are popular tools for rapid hemostasis assessment and therapeutic decision-making in this and other settings. While alcohol affects these tests in-vitro, their specific effects in-vivo are unclear. Therefore, we evaluated the effects of alcohol ingestion on ROTEM parameters.MethodsTwenty volunteers provided informed consent to drinking red wine, whisk(e)y, or vodka to a target blood alcohol concentration of 1‰ within one hour, calculated with the Widmark formula. Blood samples were collected before drinking, at a breath alcohol concentration of 0.5‰, and at 1.0‰, but no later than one hour. After each blood collection, ExTEM and FibTEM tests were performed directly "at the bedside."ResultsAll participants had a blood alcohol concentration (BAC) of 0.00‰ at the beginning. The mean BACs at the second and third collection were 0.48 and 0.76‰, respectively. There were no significant differences in the ExTEM parameters. FibTEM measurements showed a significant difference at the A10 value (13.0 vs. 14.0 mm, P = 0.014) and a trend at the maximum amplitude (maximum clot firmness 13.7 vs. 16.2 mm, P = 0.075). We saw no significant differences in fibrinolysis parameters and no hyperfibrinolysis in our ROTEM measurements.ConclusionsEthanol ingestion can impair early fibrin polymerization. These results might be of special relevance in trauma and support routine application of ROTEM/TEG in such cases.

Does State Dissociation Mediate the Relation Between Alcohol Intoxication and Deliberate Self-Harm?

Research supports the notion that alcohol intoxication is a risk factor for deliberate self-harm (DSH). However, the underlying mechanisms for this relationship are poorly understood. We aimed to determine whether alcohol-induced dissociation mediated alcohol’s effects on DSH. We used data from a dose-response study of alcohol intoxication and DSH to test the proposed model. Participants were assigned to reach target blood alcohol concentrations (BAC) ranging from 0.00% through 0.10% and then completed a behavioral measure of DSH. Dissociation was assessed using the Alcohol Dissociative Experiences Scale. BAC predicted both dissociation and DSH, but dissociation did not predict DSH. Although research on clinical populations suggests dissociation is related to DSH, our findings suggest dissociation does not mediate the effects of alcohol on self-harm.

Effect of Alcohol Intoxication on Bystander Intervention in a Vignette Depiction of Sexual Assault

Alcohol-related sexual violence remains a public health problem. Despite the popularity of sexual assault bystander intervention programs, these may be limited in addressing bystander intoxication because the effects of intoxication on intervening in a sexual assault are unknown. Therefore, we tested the effects of alcohol intoxication on the five steps of bystander intervention in a sexual assault vignette. Young adults (N = 128; 50% women) were randomly assigned to consume alcohol (target blood alcohol concentration = 0.08%; n = 64) or a nonalcoholic control beverage (n = 64) in a bar-laboratory. Next, participants were presented with a vignette describing events occurring in a convivial drinking context that ends with nonconsensual sexual behavior. Latané and Darley's bystander intervention model steps were assessed in a semistructured interview. Participants in the control condition recalled the story more accurately (Step 1: notice the event) and reported greater risk/need for intervention (Step 2), but they did not differ on the latter three steps of bystander intervention compared with alcohol-condition participants. Intoxication effects were similar for men and women. Furthermore, risk/need for intervention (Step 2) partially mediated the effect of alcohol condition on personal responsibility (Step 3) and relative benefits versus costs from intervening (Step 4). Prevention programs should consider the effects of alcohol on detecting a sexual assault and the need to intervene. If intoxicated bystanders do not detect a sexual assault, then bystanders will not reach the crucial steps (i.e., taking responsibility for intervening; willingness and ability to intervene) required to intervene successfully.

Inter-laboratory proficiency results of blood alcohol determinations at clinical and forensic laboratories in Italy

BackgroundInter-laboratory proficiency schemes are widely used to control the performance of clinical and forensic toxicology laboratories. In 2016 the Laboratory of Environmental Hygiene and Forensic Toxicology — Venice (Italy) initiated an inter-laboratory proficiency test of blood–alcohol analysis. The number of participating laboratories gradually increased from 26 to 36. Furthermore, a few clinical laboratories were included if gas chromatographic (GC) methods were used for blood alcohol analysis. ProcedureWhole blood was obtained from the Blood Transfusion Centre of the Venice Hospital and a mixture of sodium fluoride and potassium oxalate was added as a preservative and anticoagulant, respectively. Aliquots of the blood were spiked with certified pure ethanol to obtain target blood–alcohol concentrations (BACs) ranging from 0 to 5.0g/L. Two blood samples (4mL each) were included in each shipment to the participating laboratories. The laboratories were asked to provide information about number of replicate BAC determinations they made, the types of ethanol reference standards used, and inherent measurement uncertainty. The aim of the testing was to obtain a mean consensus value for the target BAC and to assess inter-laboratory imprecision. All procedures for registration and submission of results were done on-line. A confidential report and statistical evaluations were returned to the participants one week later. Analytical methodsAll participants used head-space GC (HS-GC) for the analysis of ethanol in blood. More than 85% of participants used HS-GC with flame-ionization detection, whereas the others used mass spectrometry (MS) as a detector. More than 40% of the participating laboratories kept the blood samples frozen (−20°C) prior to analysis, whereas the others used refrigeration (+4°C). The preliminary validation tests showed that there were no statistically significant differences between BAC in frozen or refrigerated samples for a period of 20 days. Results and conclusionThe statistical evaluation of results was done using an iterative procedure known as Algorithm A (ISO 13528:2015, C.3.1). This provides robust estimates for mean and standard deviation between laboratories and these were used as consensus values. More than 85% of participants provided satisfactory results (z-score <1) and 94% of laboratories were within z-score <2, based on five control samples. When a blood sample without any alcohol (blank) was sent for analysis, laboratories reported this as zero, 0.00g/L, below limit of detection (LOD) or not detected. Some type of consensus should be reached for reporting blank samples.

Faster alcohol metabolism is associated with increased stimulation and within session consumption.

Variability in subjective response (SR) to alcohol predicts drinking and the development of Alcohol Use Disorders (AUDs). Although both alcohol pharmacokinetics (i.e., absorption and metabolism) and SR are impacted by aspects of the drinking situation (e.g., rate of consumption), relations between individual differences in pharmacokinetics and SR have received little attention. The current study examined the extent to which alcohol pharmacokinetics impact SR and drinking during a single alcohol administration session. A total of 119 (67% male) social drinkers were administered a dose of alcohol with a target blood alcohol concentration (BAC) of 0.08g%. The Biphasic Alcohol Effects Scale was administered twice at matched ascending and descending limb BACs following alcohol consumption to assess SR. Pharmacokinetic properties (absorption and metabolism) were inferred using multiple BAC readings to calculate the area under the curve during the ascending limb (absorption) and descending limb (metabolism). Following completion of SR measures, an ad libitum taste rating task utilizing nonalcoholic beer was implemented to assess voluntary 'alcohol' consumption. Results indicated that participants who metabolized alcohol more quickly maintained a greater level of subjective stimulation on the descending limb. Faster metabolism was indirectly related to ad lib nonalcoholic beer consumption through greater maintenance of stimulant effects. Absorption did not significantly predict SR or within session drinking. The results increase understanding of SR variability and suggest that heightened stimulation that is sustained across limbs of the BAC curve may increase risk for excessive consumption. Individual differences in alcohol metabolism may be an identifiable biomarker of this high risk pattern of SR. (PsycINFO Database Record

Acute Alcohol Consumption Directly Increases HIV Transmission Risk: A Randomized Controlled Experiment.

Alcohol consumption has frequently been purported as a driver of condomless sex and HIV transmission, but to date, experimental evidence for the causal risk-taking impact of alcohol among HIV-positive populations is lacking. The present experiment sought to determine whether acute alcohol consumption has a direct causal impact on condomless sex intentions among HIV-positive men-who-have-sex-with-men (MSM), and to assess whether alcohol's impact differs between MSM who are HIV-positive versus HIV-negative. In a randomized controlled alcohol administration experiment, HIV-positive and HIV-negative MSM were brought into a specialized barroom laboratory and randomly assigned to beverage consumption condition: alcohol (target blood alcohol concentration = 0.080%), placebo alcohol (target blood alcohol concentration = 0.000%), or water (control). Participants then underwent a video-based sexual arousal manipulation (sexually aroused/nonaroused) and indicated their intentions to engage in condom-protected and condomless sexual acts in a standardized paradigm. The primary outcome entailed intentions to engage in condomless receptive and condomless insertive anal sex. A total of 282 MSM (141 HIV-positive; 141 HIV-negative) completed experimental procedures. MSM who received alcohol reported significantly stronger intentions to engage in condomless sex than those who received placebo alcohol or water (F(1,274) = 9.43, P = 0.002). The impact of alcohol did not differ between HIV-positive and HIV-negative MSM (F(1,274) = 1.86, P = 0.174). The present investigation entailed the first risk-focused alcohol administration experiment to involve an HIV-positive sample, and results demonstrated that consuming alcohol had an independent, causal impact on intentions to engage in sexual behaviors that can result in HIV transmission. Findings strongly suggest that alcohol-focused initiatives should be incorporated into HIV prevention efforts.

When does alcohol hurt? A driving simulator study

World-wide, alcohol is still a major cause of traffic accidents. The dose-related accident risk function has been found in a large number of risk studies. A plethora of laboratory studies has examined the effect of alcohol with regard to different information processing capabilities of drivers. Summarizing the results, alcohol effects occur at lower blood alcohol concentrations (BAC) the more complex the tasks get. However, in contrast, typical alcohol-related crashes are frequently single vehicle crashes but not so often crashes in complex situations like at intersections. It may be that the subjective assessment of the traffic situation and the adaptation of behavior under the influence of alcohol plays a major role in accident causation.In order to examine this hypothesis, two driving simulator studies were conducted at a target BAC of 0.5g/l comparing two (alcohol vs. placebo; n=48, Experiment 1) and three (sober, placebo and alcohol; n=63, Experiment 2) groups of subjects in two critical scenarios. The first scenario was a seemingly easy traffic situation and was supposed to lead to a relaxed driving behavior under alcohol. The second scenario involved a complex intersection situation where especially drivers under the influence of alcohol should try to concentrate and compensate their experienced alcohol effects. In all scenarios, a critical object appeared suddenly and the driver had to react fast in order to prevent a (simulated) accident.Overall, the results support the hypothesis. Accidents were more frequent for alcohol drivers as compared to placebo/sober drivers in the easy scenario, but not the complex one. The initial speed of the driver when entering the scenario seems to play a major role in the accident causation. Drivers under the influence of alcohol seem to lower their speed in complex scenarios, possibly to thus counteract alcohol effects. In seemingly easy scenarios this does not seem necessary for them and the arousing effect of alcohol may contribute to driving faster. The results are summarized in a model of alcohol-related crashes. Further in-depth analyses of real crashes would be an interesting next step to further corroborate this model.

The effects of alcohol expectancy and intake on slot machine gambling behavior.

Background and aimsAlthough alcohol intake and gambling often co-occur in related venues, there is conflicting evidence regarding the effects of alcohol expectancy and intake on gambling behavior. We therefore conducted an experimental investigation of the effects of alcohol expectancy and intake on slot machine gambling behavior.Methods Participants were 184 (females = 94) individuals [age range: 18–40 (mean = 21.9) years] randomized to four independent conditions differing in information/expectancy about beverage (told they received either alcohol or placebo) and beverage intake [actually ingesting low (target blood alcohol concentration [BAC] < 0.40 mg/L) vs. moderate (target BAC > 0.40 mg/L; ≈0.80 mg/L) amounts of alcohol]. All participants completed self-report questionnaires assessing demographic variables, subjective intoxication, alcohol effects (stimulant and sedative), and gambling factors (behavior and problems, evaluation, and beliefs). Participants also gambled on a simulated slot machine.ResultsA significant main effect of beverage intake on subjective intoxication and alcohol effects was detected as expected. No significant main or interaction effects were detected for number of gambling sessions, bet size and variation, remaining credits at termination, reaction time, and game evaluation.ConclusionAlcohol expectancy and intake do not affect gambling persistence, dissipation of funds, reaction time, or gambling enjoyment.

Laboratory analysis of risky driving at 0.05% and 0.08% blood alcohol concentration

BackgroundThe public health costs associated with alcohol-related traffic crashes are a continuing problem for society. One harm reduction strategy has been to employ per se limits for blood alcohol concentrations (BACs) at which drivers can legally operate motor vehicles. This limit is currently 0.08% in all 50 US states. Recently, the National Transportation Safety Board proposed lowering the legal limit to 0.05% (NTSB, 2013). While research has well-validated the ability of alcohol to impair driving performance and heighten crash-risk at these BACs, relatively little is known about the degree to which alcohol might increase drivers’ risk-taking. MethodsRisk-taking was examined in 20 healthy adults who were each tested in a driving simulator following placebo and two doses of alcohol calculated to yield peak BACs of 0.08% and 0.05%, the respective current and proposed BAC limits. The drive test emphasized risk-taking by placing participants in a multiple-lane, high-traffic environment. The primary measure was how close drivers maneuvered relative to other vehicles on the road (i.e., time-to-collision, TTC). ResultsAlcohol increased risk-taking by decreasing drivers’ TTC at the 0.08% target BAC relative to placebo. Moreover, risk-taking at the 0.05% target was less than risk-taking at 0.08% target BAC. ConclusionsThese findings provide evidence that reducing the legal BAC limit in the USA to 0.05% would decrease risk-taking among drivers. A clearer understanding of the dose-response relationship between various aspects of driving behaviors, such as drivers’ accepted level of risk while driving, is an important step to improving traffic safety.

Effects of varenicline on alcohol self-administration and craving in drinkers with depressive symptoms.

Varenicline (VAR) is approved to aid in smoking cessation and has been shown to be effective for reducing alcohol consumption in heavy drinkers. Little is known, however, about treatment moderators that may influence efficacy. The current study reanalyzed data from a human laboratory study (Verplaetse et al., 2016) to determine whether VAR was more effective at reducing alcohol use among drinkers reporting symptoms of depression. Participants were 60 adults meeting DSM-IV criteria for alcohol use disorders ( n = 60) who were randomly assigned to receive VAR (1 mg/day, 2 mg/day) or placebo. Following 7 days of medication pretreatment, participants attended a laboratory testing session. They provided self-reported ratings of alcohol craving and performed an ad libitum alcohol consumption task after receiving a priming dose of alcohol (target blood alcohol concentration = 0.030 g/dL). Higher blood VAR plasma levels were associated with less alcohol craving and less drinking among participants with more depressive symptoms. Among participants with fewer depressive symptoms, VAR was associated with more drinking during the ad libitum drinking task. These findings show that depression symptoms may be a moderator of VAR efficacy in alcohol users and provides evidence for the role of nAChRs in depression and alcohol use.