Alcohol hangover recognized as a separate medical condition in ICD-11: could effective treatments be counterproductive?

Recently, the alcohol hangover has been accepted by the International Classification of Diseases - 11th revision as a separate 'child entity' to alcohol intoxication, a disease. Currently there are no marketed hangover treatments with support for clinical efficacy. Furthermore, diverse perspectives exist among healthcare professionals, policymakers, and alcohol consumers regarding the necessity and desirability of developing such treatments.

Alcohol hangover versus dehydration revisited: The effect of drinking water to prevent or alleviate the alcohol hangover.

The alcohol hangover is a combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero. A popular theory suggests that dehydration is the primary cause of alcohol hangover and that the consumption of water could alleviate hangover symptoms. Here, the current evidence on the relationship between hangover severity, thirst, and water consumption is summarized. The positive correlations of the amount of water consumed with both hangover severity and thirst suggest that both dehydration and the hangover are co-occurring after-effects of alcohol consumption. While hangovers were typically relatively enduring, dehydration effects were usually mild and short-lasting. Survey data revealed that water consumption during or directly after alcohol consumption had only a modest effect in preventing next-day hangover. Also, the amount of water consumed during hangover was not related to changes of hangover severity and thirst. Thus, water consumption was not effective to alleviate the alcohol hangover. Taken together, these data suggests that alcohol hangover and dehydration are two co-occurring but independent consequences of alcohol consumption.

Alignment of Consumers' Expected Brain Benefits from Food and Supplements with Measurable Cognitive Performance Tests.

Consumers often cite cognitive improvements as reasons for making dietary changes or using dietary supplements, a motivation that if leveraged could greatly enhance public health. However, rarely is it considered whether standardized cognitive tests that are used in nutrition research are aligned to outcomes of interest to the consumer. This knowledge gap presents a challenge to the scientific substantiation of nutrition-based cognitive health benefits. Here we combined focus group transcript review using reflexive thematic analysis and a multidisciplinary expert panel exercise to evaluate the applicability of cognitive performance tools/tasks for substantiating the specific cognitive benefits articulated by consumers with the objectives to (1) understand how consumers comprehend the potential benefits of nutrition for brain health, and (2) determine the alignment between consumers desired brain benefits and validated tests and tools. We derived a 'Consumer Taxonomy of Cognitive and Affective Health in Nutrition Research' which describes the cognitive and affective structure from the consumers perspective. Experts agreed that validated tests exist for some consumer benefits including focused attention, sustained attention, episodic memory, energy levels, and anxiety. Prospective memory, flow, and presence represented novel benefits that require the development and validation of new tests and tools. Closing the gap between science and consumers and fostering co-creative approaches to nutrition research are critical to the development of products and dietary recommendations that support realizable cognitive benefits that benefit public health.

The association between COVID-19 related income loss and diet quality: The mediating role of distress.

The COVID-19 lockdowns saw many individuals lose income, experience distress and increase intake of foods that would typically be considered less 'healthy' (more processed and less fresh produce). Establishing whether there are direct and indirect links between these variables would be of benefit in preparing for similar future events but also has implications for the current global financial climate, where many are experiencing relative decreases in income. Adults in two locations (UK and Australia) (N = 917) completed online questionnaires to explore the impact of the first COVID-19 lockdown on their change in income, emotional wellbeing (depression, anxiety, stress, loneliness), resilience and diet quality. A structural equation model revealed that income loss was indirectly associated with diet quality via distress. As such, the greater the loss of income experienced, the more distress reported; distress was then directly associated with a less nutritious diet. This pattern of results existed when data from both countries were combined but also when they were modelled individually. Our findings indicate that where individuals experience a sudden reduction of income there are likely to be negative consequences for both mental and physical health. It is plausible that these findings would extend to other circumstances in which sudden loss of income may be experienced such as reductions in state social care, rising inflation and interest rates and sudden increases to the general cost of living.

Effects of a Flavonoid-Rich Blackcurrant Beverage on Markers of the Gut-Brain Axis in Healthy Females: Secondary Findings From a 4-Week Randomized Crossover Control Trial.

The microbiota-gut-brain axis is a promising target to alleviate the growing burden of neurologic and mental health disorders. Dietary polyphenols act on multiple components of the microbiota-gut-brain axis, but this complex relationship requires further attention. This randomized, placebo-controlled, double-blind, crossover trial (ACTRN12622000850774) compared 4 wk of a commercially available flavonoid-rich blackcurrant beverage (FBB; 151 mg anthocyanins, 308 mg total polyphenols) with placebo in 40 healthy females (18-45 y). The primary outcome of stress reactivity was assessed by change in present feelings of stress, mood, and fatigue before and after completing a 20-min cognitive stressor [Purple multitasking framework (MTF)]. Secondary end points included cognitive performance (MTF), mood [profile of mood states (POMS)], sleep (Pittsburgh Sleep Quality Index), fecal microbiome composition and functional potential (shotgun sequencing), and blood biomarker concentrations (brain-derived neurotrophic factor, tryptophan, kynurenine, and interleukin 6). Statistical analyses were conducted on an intention-to-treat basis using linear mixed-effect models. Thirty-eight participants completed both intervention arms. There was no significant treatment effect on the primary outcome of stress reactivity. Compared with placebo, working memory (letter retrieval scores from MTF), and anxiety/tension and anger/hostility domains of the POMS improved with FBB supplementation (time × intervention interaction; P < 0.05). There were no treatment effects on gut microbiome composition or functional potential. Baseline abundances of Bifidobacterium genera and species (Bifidobacterium longum and Bifidobacterium bifidum) tended to be higher in participants with the greatest improvements in letter retrieval scores with FBB supplementation (nominally significant, P < 0.05). In conclusion, 4-wk FBB supplementation improved secondary outcomes of working memory performance during multitasking and mood outcomes in healthy adult females. These results should be confirmed in a larger cohort with a longer duration of follow-up.

Towards consistency in dietary pattern scoring: standardising scoring workflows for healthy dietary patterns using 24-h recall and two variations of a food frequency questionnair.

Healthy dietary patterns such as the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) have been evaluated for their potential association with health outcomes. However, the lack of standardisation in scoring methodologies can hinder reproducibility and meaningful cross-study comparisons. Here we provide a reproducible workflow for generating the MeDi, DASH and MIND dietary pattern scores from frequently used dietary assessment tools including the 24-h recall tool and two variations of FFQ. Subjective aspects of the scoring process are highlighted and have led to a recommended reporting checklist. This checklist enables standardised reporting with sufficient detail to enhance the reproducibility and comparability of their outcomes. In addition to these aims, valuable insights in the strengths and limitations of each assessment tool for scoring the MeDi, DASH and MIND diet can be utilised by researchers and clinicians to determine which dietary assessment tool best meets their needs.

Neuroimaging Insights: Kava's (Piper methysticum) Effect on Dorsal Anterior Cingulate Cortex GABA in Generalized Anxiety Disorder.

Generalised Anxiety Disorder (GAD) is a prevalent, chronic mental health disorder. The measurement of regional brain gamma-aminobutyric acid (GABA) offers insight into its role in anxiety and is a potential biomarker for treatment response. Research literature suggests Piper methysticum (Kava) is efficacious as an anxiety treatment, but no study has assessed its effects on central GABA levels. This study investigated dorsal anterior cingulate (dACC) GABA levels in 37 adult participants with GAD. GABA was measured using proton magnetic resonance spectroscopy (1H-MRS) at baseline and following an eight-week administration of Kava (standardised to 120 mg kavalactones twice daily) (n = 20) or placebo (n = 17). This study was part of the Kava for the Treatment of GAD (KGAD; ClinicalTrials.gov: NCT02219880), a 16-week intervention study. Compared with the placebo group, the Kava group had a significant reduction in dACC GABA (p = 0.049) at eight weeks. Baseline anxiety scores on the HAM-A were positively correlated with GABA levels but were not significantly related to treatment. Central GABA reductions following Kava treatment may signal an inhibitory effect, which, if considered efficacious, suggests that GABA levels are modulated by Kava, independent of reported anxiety symptoms. dACC GABA patterns suggest a functional role of higher levels in clinical anxiety but warrants further research for symptom benefit. Findings suggest that dACC GABA levels previously un-examined in GAD could serve as a biomarker for diagnosis and treatment response.

A Mediterranean Diet and Walking Intervention to Reduce Cognitive Decline and Dementia Risk in Independently Living Older Australians: The MedWalk Randomized Controlled Trial Experimental Protocol, Including COVID-19 Related Modifications and Baseline Characteristics.

BACKGROUND: Several clinical trials have examined diet and physical activity lifestyle changes as mitigation strategies for risk factors linked to cognitive decline and dementias such as Alzheimer's disease. However, the ability to modify these behaviors longer term, to impact cognitive health has remained elusive. OBJECTIVE: The MedWalk trial's primary aim is to investigate whether longer-term adherence to a Mediterranean-style diet and regular walking, delivered through motivational interviewing and cognitive-behavioral therapy (MI-CBT), can reduce age-associated cognitive decline and other dementia risk factors in older, independently living individuals without cognitive impairment. METHODS: MedWalk, a one-year cluster-randomized controlled trial across two Australian states, recruited 60-90-year-old people from independent living retirement villages and the wider community. Participants were assigned to either the MedWalk intervention or a control group (maintaining their usual diet and physical activity). The primary outcome is 12-month change in visual memory and learning assessed from errors on the Paired Associates Learning Task of the Cambridge Neuropsychological Test Automated Battery. Secondary outcomes include cognition, mood, cardiovascular function, biomarkers related to nutrient status and cognitive decline, MI-CBT effectiveness, Mediterranean diet adherence, physical activity, quality of life, cost-effectiveness, and health economic evaluation.Progress and Discussion:Although COVID-19 impacts over two years necessitated a reduced timeline and sample size, MedWalk retains sufficient power to address its aims and hypotheses. Baseline testing has been completed with 157 participants, who will be followed over 12 months. If successful, MedWalk will inform interventions that could substantially reduce dementia incidence and ameliorate cognitive decline in the community. TRIAL REGISTRATION: Registered on the Australia New Zealand Clinical Trials Registry ANZCTR 12620000978965 (https://www.anzctr.org.au).

Effect of kava (Piper methysticum) on peripheral gene expression among individuals with generalized anxiety disorder: A post hoc analysis of a randomized controlled trial.

Kava is a South Pacific plant-based medicine with anxiolytic properties, but little is known about the impact kava has on gene expression or whether gene expression can serve as a marker of kava response. This study aimed to determine whether kava treatment alters the expression of genes with physiological relevance to anxiety pathophysiology and whether the baseline expression of these physiologically relevant genes modifies the efficacy of kava treatment. In this post hoc analysis, we examined the expression of 48 genes relevant to the pathophysiology of anxiety collected from a double-blind randomized controlled trial that assessed the efficacy of kava treatment in generalized anxiety disorder. Peripheral blood gene expression was measured in 71 (34 kava, 37 placebo) adults at baseline and in 40 (19 kava, 21 placebo) after 8 weeks of treatment by reverse transcription polymerase chain reaction (PCR). Results revealed that kava decreased the expression of a subunit of the GABAA -rho receptor gene (GABRR2) and catechol-O-methyltransferase (COMT), a gene related to catecholamine metabolism. Kava efficacy was not found to be modified by baseline (pretreatment) expression of relevant genes. Although these results did not withstand statistical correction for multiple comparisons and require external validation, they support the notion that kava's mechanism of action includes interaction with GABAergic and catecholaminergic systems.

Nutrient Therapy for the Improvement of Fatigue Symptoms.

Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom of several conditions and negatively impacts the quality of life of those affected. Fatigue is often a symptom of concern for people suffering from conditions such as fibromyalgia, chronic fatigue syndrome, cancer, and multiple sclerosis. Vitamins and minerals, playing essential roles in a variety of basic metabolic pathways that support fundamental cellular functions, may be important in mitigating physical and mental fatigue. Several studies have examined the potential benefits of nutrients on fatigue in various populations. The current review aimed to gather the existing literature exploring different nutrients' effects on fatigue. From the searches of the literature conducted in PubMed, Ovid, Web of Science, and Google scholar, 60 articles met the inclusion criteria and were included in the review. Among the included studies, 50 showed significant beneficial effects (p < 0.05) of vitamin and mineral supplementation on fatigue. Altogether, the included studies investigated oral or parenteral administration of nutrients including Coenzyme Q10, L-carnitine, zinc, methionine, nicotinamide adenine dinucleotide (NAD), and vitamins C, D and B. In conclusion, the results of the literature review suggest that these nutrients have potentially significant benefits in reducing fatigue in healthy individuals as well as those with chronic illness, both when taken orally and parenterally. Further studies should explore these novel therapies, both as adjunctive treatments and as sole interventions.

Post-Prandial Cognitive and Blood Pressure Effects of a DHA-Rich Omega-3 Powder in Middle-Aged Males: A Pilot Study.

The use of omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplements is increasingly common among middle-aged and older adults. Users of ω-3 PUFA supplements often report using such supplements to support cognitive health, despite mixed findings reported within the ω-3 PUFA literature. To date, very few studies have explored cognitive effects in distinctly middle-aged (40 to 60 years) adults, and none have examined the acute effects (in the hours following a single dose) on cognitive performance. The current study evaluated whether a single dose of ω-3 PUFA (4020 mg docosahexaenoic acid and 720 mg eicosapentaenoic acid) influences cognitive performance and cardiovascular function in middle-aged males. Cognitive performance and cardiovascular function were assessed before and 3.5-4 h after consumption of a high dose of ω-3 PUFA (DHA + EPA) or placebo, incorporated into a standardized meal (i.e., single serve of Greek yogurt). In this study of middle-aged males, no significant differential treatment effects were observed for cognitive performance. However, a significant reduction in aortic systolic blood pressure (pre-dose to post-dose) was apparent following consumption of the ω-3 PUFA (DHA + EPA) treatment (mean difference = -4.11 mmHg, p = 0.004) but not placebo (mean difference = -1.39 mmHg, p = 0.122). Future replication in a sample comprising females, as well as patients with hypertension, is merited.

The efficacy of a combination of naproxen and fexofenadine (SJP - 002) to inhibit the symptoms that are associated with viral upper respiratory tract infection: Four case reports of individuals with common cold.

Key Clinical Message: There is no effective treatment that reduces both the severity and duration of a common cold episode. SJP - 002 (naproxen and fexofenadine) reduced symptom severity by two-third, and the duration of the common cold episode approximately by half. Abstract: The common cold is one of the most frequently experienced immune-related complaints. At present, available treatments have limited efficacy in inhibiting symptoms associated with upper respiratory tract infection, nor do they significantly shorten the duration of common cold episodes. Four case reports are presented of individuals with a common cold. Three of them self-administered the combination of naproxen and fexofenadine (SJP - 002). Results of one individual were compared to her spouse, who did not take SJP - 002 to treat common cold, while two other individuals took SJP - 002 and compared symptom severity with another common cold episode they experienced previously without taking SJP - 002. SJP - 002 reduced the severity of symptoms associated with upper respiratory tract infection by two-third and reduced the duration of the common cold episode approximately by half. In conclusion, SJP - 002 reduced the severity and duration of common cold episodes. These findings warrant further investigation of SJP - 002 in double-blind, placebo-controlled clinical trials.

A combined DHA-rich fish oil and cocoa flavanols intervention does not improve cognition or brain structure in older adults with memory complaints: results from the CANN randomized, controlled parallel-design study.

BACKGROUND: There is evidence that both omega-3 long-chain polyunsaturated fatty acids (PUFAs) (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) and cocoa flavanols can improve cognitive performance in both healthy individuals and in those with memory complaints. However, their combined effect is unknown. OBJECTIVES: To investigate the combined effect of EPA/DHA and cocoa flavanols (OM3FLAV) on cognitive performance and brain structures in older adults with memory complaints. METHODS: A randomized placebo-controlled trial of DHA-rich fish oil (providing 1.1 g/d DHA and 0.4 g/d EPA) and a flavanol-rich dark chocolate (providing 500 mg/d flavan-3-ols) was conducted in 259 older adults with either subjective cognitive impairment or mild cognitive impairment. Participants underwent assessment at baseline, 3 mo, and 12 mo. The primary outcome was the number of false-positives on a picture recognition task from the Cognitive Drug Research computerized assessment battery. Secondary outcomes included other cognition and mood outcomes, plasma lipids, brain-derived neurotrophic factor (BDNF), and glucose levels. A subset of 110 participants underwent structural neuroimaging at baseline and at 12 mo. RESULTS: 197 participants completed the study. The combined intervention had no significant effect on any cognitive outcomes, with the exception of reaction time variability (P = 0.007), alertness (P < 0.001), and executive function (P < 0.001), with a decline in function observed in the OM3FLAV group (118.6 [SD 25.3] at baseline versus 113.3 [SD 25.4] at 12 mo for executive function) relative to the control, and an associated decrease in cortical volume (P = 0.039). Compared with the control group, OM3FLAV increased plasma HDL, total cholesterol ratio (P < 0.001), and glucose (P = 0.008) and reduced TG concentrations (P < 0.001) by 3 mo, which were sustained to 12 mo, with no effect on BDNF. Changes in plasma EPA and DHA and urinary flavonoid metabolite concentrations confirmed compliance to the intervention. CONCLUSIONS: These results suggest that cosupplementation with ω-3 PUFAs and cocoa flavanols for 12 mo does not improve cognitive outcomes in those with cognitive impairment. This trial was registered at clinicaltrials.gov as NCT02525198.

Test-retest reliability of single-item assessments of immune fitness, mood, and quality of life.

The use of single-item assessments is increasingly important and popular, as these enable quick real-time assessments in clinical practice or research. In this study we investigated the test-retest reliability of single-item assessments of mood ("stress", "anxiety", "depression", "fatigue", "loneliness", "being active", "optimism", and "happiness"), quality of life, and immune fitness in N = 108 participants. The analysis revealed high test-retest correlations between the single-item assessments (r = 0.67 to 0.90), moderate to excellent intraclass correlations (r = 0.672 to 0.889), and the Bland-Altman analysis revealed agreement between all test-retest assessments, except for depression. Taken together, it can be concluded that the single-item assessments of mood, quality and immune fitness have a good test-retest reliability. This strengthens the rationale for using these single item assessments.

Corrigendum: The association between diet and cardio-metabolic risk on cognitive performance: A cross-sectional study of middle-aged Australian adults.

[This corrects the article DOI: 10.3389/fnut.2022.862475.].

Differences in Next-Day Adverse Effects and Impact on Mood of an Evening of Heavy Alcohol Consumption between Hangover-Sensitive Drinkers and Hangover-Resistant Drinkers.

The combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero, are collectively referred to as the alcohol hangover. Previous research revealed that 10 to 20% of drinkers claim not to experience next-day hangovers. Past studies were usually limited to single timepoint assessments. The aim of the current semi-naturalistic study was to compare the next-day effects of an evening of alcohol consumption of self-reported hangover-resistant drinkers (n = 14) with those of a group of self-reported hangover-sensitive drinkers (n = 15) at hourly timepoint throughout the day (09:30 until 15:30). Assessments of 23 hangover symptoms, mood (Profiles of Mood States-Short Form), and daytime sleepiness (Karolinska Sleepiness Scale) were made hourly after both an alcohol day and an alcohol-free control day. Additional morning assessments were made for mood (State-Trait Anxiety Inventory-Y, Beck's Depression Inventory-II), risk-taking behavior (RT-18), past night sleep (Groningen Sleep Quality Scale), alcohol consumption, and activities during the test days. No significant differences were found regarding the amount of alcohol consumed and the total sleep time of the two groups. The hangover-sensitive group reported having a hangover as well as the presence of a variety of hangover-related symptoms, which were most severe in the morning and then gradually decreased during the day. The most frequently reported and most severe symptoms were sleepiness and fatigue, concentration problems, and headache. In contrast, the hangover-resistant group reported the absence of a hangover and the presence and severity of next-day symptoms did not significantly differ from the control day, except for increased fatigue and reduced vigor. The next-day effects on sleepiness-related complaints and vigor were significantly more pronounced among hangover-sensitive drinkers compared to hangover-resistant drinkers. In conclusion, contrary to hangover-resistant drinkers, hangover-sensitive drinkers report a variety of hangover symptoms that gradually ease during the day, but are still present in the afternoon.

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action.

Given the rise in worldwide chronic diseases, supplemented by an aging population, the volume of global major surgeries, encompassing cardiac and orthopedic procedures is anticipated to surge significantly. Surgical trauma can be accompanied by numerous postoperative complications and metabolic changes. The present review summarized the results from studies assessing the effects of orthopedic and cardiovascular surgery on vitamin concentrations, in addition to exploring the possible mechanisms associated with changes in concentrations. Studies have revealed a potentially severe depletion in plasma/serum concentrations of numerous vitamins following these surgeries acutely. Vitamins C, D and B1 appear particularly vulnerable to significant depletions, with vitamin C and D depletions consistently transpiring into inadequate and deficient concentrations, respectively. The possible multifactorial mechanisms impacting postoperative vitamin concentrations include changes in hemodilution and vitamin utilization, redistribution, circulatory transport and absorption. For a majority of vitamins, there has been a lack of investigation into the effects of both, cardiac and orthopedic surgery. Additionally, studies were predominantly restricted to short-term postoperative investigations, primarily performed within the first postoperative week of surgery. Overall, results indicated that further examination is necessary to determine the severity and clinical significance of the possible depletions in vitamin concentrations that ensue cardiovascular and orthopedic surgery.

Investigating the Effects of a Multinutrient Supplement on Cognition, Mood and Biochemical Markers in Middle-Aged Adults with 'Optimal' and 'Sub-Optimal' Diets: A Randomized Double Blind Placebo Controlled Trial.

Background: Previous randomized controlled trials examining cognitive and mood effects of combination multivitamin supplements in healthy, non-clinical adults have reported mixed results. One purported explanation for this is that the dietary status of participants at the start of supplement interventions may influence the magnitude of the effect of supplementation. Methods: In this study, we evaluated the effect of a multinutrient formula containing B group vitamins, Bacopa monniera and Ginkgo biloba on memory, attention, mood and biochemical markers of nutrient status in middle-aged adults (M = 52.84 years, n = 141) with 'optimal' and 'sub-optimal' diets over 12 weeks. We hypothesised that active supplementation would differentially improve memory and attention in those with a 'sub-optimal' diet. Results: Mixed model, repeated measures analysis revealed that, in comparison to placebo, active treatment was associated with significant increases in B vitamin status (B1, B6, B12). Regarding behavioural outcomes there was no significant benefit to memory (F(1, 113.51) = 0.53, p = 0.470) nor attention (F(1,113.77) = 1.89, p = 0.171) in the whole cohort. Contrary to our hypothesis, there was a significant beneficial effect of supplementation on attentional performance in individuals with an 'optimal' diet prior to supplementation (F(1,57.25) = 4.94, p = 0.030). In the absence of a main effect of supplementation across the entire cohort, there were also a number of significant three-way interactions (treatment by time by diet group) detected in secondary outcomes including lower state anxiety and mental fatigue in those with an 'optimal' diet. Conclusion: These findings suggest that the cognitive benefit of B vitamin and herbal supplementation may be dependent on diet quality, supporting the concepts of 'co-nutrient optimisation' and interdependency of nutrients. This warrants further investigation. This study advocates characterising the diet of participants prior to supplementation as it may influence the effect of a nutraceutical intervention.

Effects of alcohol intoxication on driving performance, confidence in driving ability, and psychomotor function: a randomized, double-blind, placebo-controlled study.

RATIONALE: Alcohol-induced driving impairment can occur with any departure from a zero-blood alcohol concentration (BAC). Because intoxication is characterised by impaired judgement, drivers under the influence of alcohol may overestimate their capacity to safely operate a vehicle. OBJECTIVES: This study examined the effects of alcohol on driving performance, four-choice reaction time (FCRT), and self-rated confidence in driving ability. It specifically focused on alcohol doses equal to commonly enforced legal BAC limits (i.e. 0.05% and 0.08%). METHODS: A randomized, double-blind, placebo-controlled design was utilised. Seventeen participants were tested in three conditions: placebo and two alcohol conditions aiming for BACs of 0.05% and 0.08%. Participants underwent a baseline FCRT task and a 1-h simulated highway driving task before completing another FCRT task and rated their confidence in their driving ability. RESULTS: The high and low alcohol dose conditions resulted in a mean BAC of 0.07%, and 0.04%, respectively (n = 17). The high BAC treatment significantly increased standard deviation of lateral position (SDLP) by 4.06 ± 5.21 cm and standard deviation of speed (SDS) by 0.69 ± 0.17 km/h relative to placebo, while confidence in driving ability remained unchanged across treatments. FCRT performance was impaired by the high BAC treatment (all < 0.01), but there we no significant differences between placebo and low BAC conditions. CONCLUSIONS: The findings of this study show that driving performance and associated psychomotor functioning become significantly impaired below legally permissible driving limits in some jurisdictions. We identified a dissociation between driving performance and subjective awareness of impairment. Despite a significantly diminished driving ability at 0.07% BAC, drivers were unaware of their impairment.