Age-related effects of alcohol on memory and memory-related brain function in adolescents and adults

Prevalence of parental supply of alcohol to minors: a systematic review

Parental supply of alcohol to minors (i.e. those under the legal drinking age) is often perceived by parents as protective against harms from drinking, despite evidence linking it with adverse alcohol-related outcomes. This systematic review describes the prevalence of parental supply of alcohol, as reported in the international literature. The review was registered with PROSPERO (CRD42020218754). We searched seven online databases (Medline, Embase, PsycINFO, CINAHL, Scopus, Web of Science and Public Health Database) and grey literature from January 2011 to December 2022 and assessed the risk of bias with the JBI Critical Appraisal Checklist. Among 58 articles included in narrative synthesis from 29 unique datasets, there was substantial variation in the definition and measurement of parental supply of alcohol. Overall prevalence rates ranged from 7.0 to 60.0% for minor-report samples, and from 24.0 to 48.0% for parent-report samples. Data indicate that parental supply prevalence is generally proportionately higher for older minors or later-stage students, for girls, and has increased over time among minors who report drinking. Literature on the prevalence of parental supply of alcohol is robust in quantity but inconsistent in quality and reported prevalence. Greater consistency in defining and measuring parental supply is needed to better inform health promotion initiatives aimed at increasing parents' awareness.

Behavioral alterations induced by intermittent ethanol intake and noise exposure in adolescent rats

Alcohol intake and exposure to noise are common activities of human adolescents performed in entertainment contexts worldwide that can induce behavioral disturbances. Therefore, the aim of the present work was to investigate in an experimental model of adolescent animals whether noise exposure and intermittent ethanol intake, when present individually or sequentially, might be able to modify different behaviors. Adolescent Wistar rats of both sexes were subjected to voluntary intermittent ethanol intake for 1 week followed by exposure to noise for 2 h and tested in a battery of behavioral tasks. Data show that males exposed to noise experienced a deficit in associative memory (AM), increase in anxiety-like behaviors (ALB) and altered reaction to novelty (RN) when compared with sham animals, whereas females also showed an increase in risk assessment behaviors (RAB) and a decrease in exploratory activity (EA). In contrast, ethanol intake induced an increase in RAB and RN in males and females, whereas females also showed a deficit in AM and EA as well as an increase in ALB. When ethanol was ingested before noise exposure, most parameters were counteracted both in male and females, but differed among sexes. In consequence, it could be hypothesized that an environmental acute stressor like noise might trigger a behavioral counteracting induced by a previous repeated exposure to a chemical agent such as ethanol, leading to a compensation of a non-adaptive behavior and reaching a better adjustment to the environment.

Alcohol Use and Prefrontal Cortex Volume Trajectories in Young Adults with Mood Disorders and Associated Clinical Outcomes

(1) Background: Alcohol use in the course of mood disorders is associated with worse clinical outcomes. The mechanisms by which alcohol use alters the course of illness are unclear but may relate to prefrontal cortical (PFC) sensitivity to alcohol. We investigated associations between alcohol use and PFC structural trajectories in young adults with a mood disorder compared to typically developing peers. (2) Methods: 41 young adults (24 with a mood disorder, agemean = 21 ± 2 years) completed clinical evaluations, assessment of alcohol use, and two structural MRI scans approximately one year apart. Freesurfer was used to segment PFC regions of interest (ROIs) (anterior cingulate, orbitofrontal cortex, and frontal pole). Effects of group, alcohol use, time, and interactions among these variables on PFC ROIs at baseline and follow-up were modeled. Associations were examined between alcohol use and longitudinal changes in PFC ROIs with prospective mood. (3) Results: Greater alcohol use was prospectively associated with decreased frontal pole volume in participants with a mood disorder, but not typically developing comparison participants (time-by-group-by-alcohol interaction; p = 0.007); however, this interaction became a statistical trend in a sensitivity analysis excluding one outlier in terms of alcohol use. Greater alcohol use and a decrease in frontal pole volume related to longer duration of major depression during follow-up (p’s < 0.05). (4) Conclusion: Preliminary findings support more research on alcohol use, PFC trajectories, and depression recurrence in young adults with a mood disorder including individuals with heavier drinking patterns.

Early life stress and substance use disorders: The critical role of adolescent substance use

Early life stress (ELS) is a well-established risk factor for many psychiatric and medical disorders, including substance use disorders (SUDs). The relationship between ELS and SUDs is complex and there are likely multiple pathways from ELS to adverse substance use outcomes. The association between ELS and substance use emerges in adolescence. Adolescence is a critical period in development during which substance exposure markedly increases risk for SUDs. Therefore, this review focuses on the literature supporting the hypothesis that ELS increases risk for the development of SUDs through its influence on adolescent substance use. We discuss studies substantiating the role of ELS in adolescent substance use and explore how internalizing and externalizing psychopathology may be antecedents of substance use in adolescence. We examine clinical work suggesting ELS sculpts the Hypothalamic-Pituitary-Adrenal (HPA) Axis and developing brain-particularly subcortical brain regions that underlie stress response, mesocorticolimbic brain systems associated with reward sensitivity, and prefrontal regions that underlie executive control-in a way that increases risk for adolescent substance use and SUDs. We further explore how substance use during adolescence alters structure and function of these same systems, and how brain changes following ELS and adolescent substance use may independently, additively, or interactively contribute to risk for addiction. We conclude by discussing how the current literature can inform interventions aimed at reducing risk for SUDs in individuals with a history of ELS.

Neuroepigenetic consequences of adolescent ethanol exposure

Adolescence is a critical developmental period characterized by ongoing brain maturation processes including myelination and synaptic pruning. Adolescents experience heightened reward sensitivity, sensation seeking, impulsivity, and diminished inhibitory self-control, which contribute to increased participation in risky behaviors, including the initiation of alcohol use. Ethanol exposure in adolescence alters memory and cognition, anxiety-like behavior, and ethanol sensitivity as well as brain myelination and dendritic spine morphology, with effects lasting into adulthood. Emerging evidence suggests that epigenetic modifications may explain these lasting effects. Focusing on the amygdala, prefrontal cortex and hippocampus, we review studies investigating the epigenetic consequences of adolescent ethanol exposure. Ethanol metabolism globally increases donor substrates for histone acetylation and histone and DNA methylation, and this chapter discusses how this can further impact epigenetic programming of the adolescent brain. Elucidation of the mechanisms through which ethanol can alter the epigenetic code at specific transcripts may provide therapeutic targets for intervention.

Associations of parental and peer cross-substance use with 12-17-year-old adolescents' problematic alcohol use: A parent-child dyadic gender analysis

BACKGROUND

Adolescent alcohol use was found to be influenced by parental and peer alcohol use. Drinking behaviors also differed by gender. However, previous studies mainly focused on adolescents' substance use in relation to the same substance use among their salient others. Hence, this study investigated the cross-substance relationships of alcohol and tobacco use of parents and peers with adolescents' problematic alcohol use, separately by gender.

METHODS

Data were derived from 4445 adolescents aged 12-17 years from the 2014 National Survey of Substance Use, a nationally representative survey in Taiwan. Problematic alcohol use was assessed using the Alcohol Use Disorders Identification Test (AUDIT). Multivariate multinomial logistic regression was used, stratified by gender.

RESULTS

For males, maternal (adjusted odds ratio [aOR] = 1.73) and peer (aOR = 2.57) alcohol use was related to social drinking (AUDIT < 2); paternal (aOR = 3.58), maternal (aOR = 2.18), peer alcohol use (aOR = 5.37), and their own tobacco use (aOR = 4.72) were related to problem drinking (AUDIT ≥ 2). For females, maternal (aOR = 2.26) and peer (aOR = 2.84) alcohol use was related to social drinking; maternal (aOR = 2.35) and peer tobacco use (aOR = 3.48), and paternal (aOR = 4.56) and peer alcohol use (aOR = 3.36) were linked to problem drinking.

CONCLUSIONS

Both male and female adolescents' alcohol use was associated with their peer alcohol use, and gender differences were found in relation to their parental and peer substance use. Specifically, the parental role-modeling of smoking was only significant in mother-daughter dyads. These findings could inform multifaceted adolescent alcohol prevention programs, tailoring for males and females and also targeting their parental and peer substance use.

Short term effects of the REAL media e-learning media literacy substance prevention curriculum: An RCT of adolescents disseminated through a community organization

BACKGROUND

The primary aim of this study was to evaluate the short-term effects of testing an e-learning program to reduce adolescent substance use and abuse. Early initiation of substance use is linked to a variety of negative outcomes, thus effective intervention programs are needed. One approach is to use media literacy to capitalize on adolescents' immersion with media in a variety of forms. We developed, implemented, and tested an engaging substance use prevention program by collaborating with a youth-oriented community partner (4-H).

METHODS

639 middle adolescents from nine U.S. states participated in an RCT of REAL media. Participants completed a series of online surveys and were randomized to use an online substance prevention program (REAL media) or serve as control (delayed program use). Self-report surveys were administered at three points in time. This short-term evaluation uses data from the pretest (Time 1) and short-term posttest three-month surveys, which measured demographics, self-efficacy to counterargue, and injunctive and descriptive substance use norms.

RESULTS

Participants who completed the REAL media program reported increased self-efficacy to counterargue and decreased positive injunctive norms compared to control participants who did not complete the program. No significant differences were observed for descriptive norms.

CONCLUSIONS

We found support for the REAL media program in changing key predictors of youth substance use demonstrating (1) the efficacy of media literacy interventions targeting adolescents and (2) that e-learning substance use prevention efforts can be adapted for and implemented through community organizations.

Oxidative Stress-Induced Brain Damage Triggered by Voluntary Ethanol Consumption during Adolescence: A Potential Target for Neuroprotection?

Alcohol consumption, in particular ethanol (EtOH), typically begins in human adolescence, often in a "binge like" manner. However, although EtOH abuse has a high prevalence at this stage, the effects of exposure during adolescence have been less explored than prenatal or adult age exposure. Several authors have reported that EtOH intake during specific periods of development might induce brain damage. Although the mechanisms are poorly understood, it has been postulated that oxidative stress may play a role. In fact, some of these studies revealed a decrease in brain antioxidant enzymes' level and/or an increase in reactive oxygen species (ROS) production. Nevertheless, although existing literature shows a number of studies in which ROS were measured in developing animals, fewer reported the measurement of ROS levels after EtOH exposure in adolescence. Importantly, neuroprotective agents aimed to these potential targets may be relevant tools useful to reduce EtOH-induced neurodegeneration, restore cognitive function and improve treatment outcomes for alcohol use disorders (AUDs). The present paper reviews significant evidences about the mechanisms involved in EtOH-induced brain damage, as well as the effect of different potential neuroprotectants that have shown to be able to prevent EtOH-induced oxidative stress. A selective inhibitor of the endocannabinoid anandamide metabolism, a flavonol present in different fruits (quercetin), an antibiotic with known neuroprotective properties (minocycline), a SOD/catalase mimetic, a potent antioxidant and anti-inflammatory molecule (resveratrol), a powerful ROS scavenger (melatonin), an isoquinoline alkaloid (berberine), are some of the therapeutic strategies that could have some clinical relevance in the treatment of AUDs. As most of these works were performed in adult animal models and using EtOH-forced paradigms, the finding of neuroprotective tools that could be effective in adolescent animal models of voluntary EtOH intake should be encouraged.

Relationship of Wine Consumption with Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD), the most threatening neurodegenerative disease, is characterized by the loss of memory and language function, an unbalanced perception of space, and other cognitive and physical manifestations. The pathology of AD is characterized by neuronal loss and the extensive distribution of senile plaques and neurofibrillary tangles (NFTs). The role of environment and the diet in AD is being actively studied, and nutrition is one of the main factors playing a prominent role in the prevention of neurodegenerative diseases. In this context, the relationship between dementia and wine use/abuse has received increased research interest, with varying and often conflicting results. Scope and Approach: With this review, we aimed to critically summarize the main relevant studies to clarify the relationship between wine drinking and AD, as well as how frequency and/or amount of drinking may influence the effects. Key Findings and Conclusions: Overall, based on the interpretation of various studies, no definitive results highlight if light to moderate alcohol drinking is detrimental to cognition and dementia, or if alcohol intake could reduce risk of developing AD.

Adolescent Vulnerability to Alcohol Use Disorder: Neurophysiological Mechanisms from Preclinical Studies

Adolescent alcohol use in human populations dramatically increases the likelihood of adult alcohol use disorder. This adolescent vulnerability is recapitulated in preclinical models which provide important opportunities to understand basic neurobiological mechanisms. We provide here an overview of GABAergic and glutamatergic neurotransmission and our current understanding of the sensitivity of these systems to adolescent ethanol exposure. As a whole, the preclinical literature suggests that adolescent vulnerability may be directly related to region-specific neurobiological processes that continue to develop during adolescence. These processes include the activity of intrinsic circuits within diverse brain regions (primarily represented by GABAergic neurotransmission) and activity-dependent regulation of synaptic strength at glutamatergic synapses. Furthermore, GABAergic and glutamatergic neurotransmission within regions/circuits that regulate cognitive function, emotion, and their integration appears to be the most vulnerable to adolescent ethanol exposure. Finally, using documented behavioral differences between adolescents and adults with respect to acute ethanol, we highlight additional circuits and regions for future study.

Ethanol Exposure Induces Microglia Activation and Neuroinflammation through TLR4 Activation and SENP6 Modulation in the Adolescent Rat Hippocampus

The ethanol-induced toll-like receptor 4 (TLR4) signal activation of microglia and neuroinflammation are observed in both adolescent and adult rat brains, but the regulatory mechanisms of some TLR4 signaling-related factors in this process are still unclear. SUMO-specific protease 6 (SENP6) inhibits neuroinflammation by dampening nuclear factor kappa-B (NF-κB) activation via the de-SUMOylation of NF kappa-B essential modulator (NEMO). This study investigates the effects of long-term ethanol consumption on neuroinflammation in the hippocampus of adolescent rats and the regulatory roles of TLR4 and SENP6. Twenty-one days of ethanol exposure in adolescent rats were used to develop an animal model. The number of microglia, microglial activation, and the expression of TLR4 in the hippocampus of adolescent rats were examined by immunoreactivity. The levels of TLR4, activation of NF-κB including IkB-α and p-NF-κB-p65, and SENP6 were measured by western blotting. Proinflammatory cytokines including TNF-α, IL-1β, and IL-6 were measured by enzyme-linked immunosorbent assay. The NF-κB activation and proinflammatory cytokines released in overexpressed SENP6 and siRNA targeting SENP6 microglial cells after treatment with ethanol were estimated in vitro. This study found that alcohol exposure increased the number of activated microglia and the levels of p-NF-κB-p65 and proinflammatory cytokines, while it decreased the SENP6 level in wild-type rats, but not in TLR4 knockout rats. The ethanol-induced increases of p-NF-κB-p65, TNF-α, and IL-1β were dampened by overxpression of SENP6 and enhanced in SENP6-siRNA microglia. Our data suggest that ethanol exposure during adolescence induces the microglia-mediated neuroinflammation via TLR4 activation, and SENP6 plays an essential role in dampening NF-κB activation and neuroinflammation.

Autophagy alleviates ethanol-induced memory impairment in association with anti-apoptotic and anti-inflammatory pathways

Chronic excessive drinking leads to a wide spectrum of neurological disorders, including cognitive deficits, such as learning and memory impairment. However, the neurobiological mechanisms underlying these deleterious changes are still poorly understood. We conducted a comprehensive study to investigate the role and mechanism of autophagy in alcohol-induced memory impairment. To establish an ethanol-induced memory impairment mouse model, we allowed C57BL/6J mice intermittent access to 20% ethanol (four-bottle choice) to escalate ethanol drinking levels. Memory impairment was confirmed by a Morris water maze test. We found that mice exposed to EtOH (ethanol) and EtOH combined with the autophagy inhibitor 3-methyladenine (3-MA) showed high alcohol intake and blood alcohol concentration. We confirmed that the EtOH group exhibited notable memory impairment. Inhibition of autophagy by 3-MA worsened ethanol-induced memory impairment. Ethanol induced autophagy in the hippocampus of mice as indicated by western blotting, electron microscopy, RT-qPCR, and fluorescence confocal microscopy. We determined that the mTOR/BECN1 (S14) pathway is involved in ethanol-induced autophagy in vivo. Further, ethanol-induced autophagy suppressed the NLRP3 inflammatory and apoptosis pathways in the hippocampus in mice and in vitro. These findings suggest that autophagy activation in hippocampal cells alleviates ethanol-induced memory impairment in association with anti-apoptotic and anti-inflammatory pathways.

The intermittent administration of ethanol during the juvenile period produces changes in the expression of hippocampal genes and proteins and deterioration of spatial memory

BACKGROUND

Binge drinking is a pattern of alcohol intake characterized by excessive and intermittent alcohol consumption over a very short period of time that is more used during adolescence. We aim to compare the lasting effects of a chronic-moderate vs. this intermittent-excessive way of alcohol intake during adolescence in spatial memory and in the expression of glutamatergic receptors and GSK3β activity.

METHODS

Adolescent male Wistar rats were given ethanol/saline i.p. injections in four different groups: High-I (4 g/kg of a 25% (vol/vol) every 3 days), Low-I (1 g/kg of a 5% (vol/vol) every 3 days), M (0.3 g/kg of a 2.5% (vol/vol) daily) and Control (C, sterile isotonic saline daily). Rats received ethanol for up to five 3-day cycles. Spatial memory was measured by spontaneous alternation in the Y-Maze. Gene and protein expression of hippocampal proteins were also analysed.

RESULTS

Both high- and low-intermittent ethanol administration produced spatial memory impairment and changes in glutamatergic receptors gene expression were observed regardless of the pattern of exposure. High doses of intermittent alcohol administration produced an increase of phosphorylation of GSK3β Ser9. Moreover, moderate alcohol administration produced a down-regulation of the AMPAR 2/3 ratio despite lack of spatial memory deficits.

CONCLUSIONS

Excessive and intermittent ethanol exposure during adolescence impaired the spatial memory processes during adulthood regardless of the amount of alcohol administered. Moreover, chronic-moderate and intermittent pattern induced changes in the expression of glutamatergic receptors. In addition, high-intermittent ethanol exposure during adolescence inactivated GSK3β by increasing its phosphorylation in Ser9.

Factors Associated with Parents' Belief in the Appropriateness of Providing Alcohol to their Child

BACKGROUND

Parental provision of alcohol to their underage child has been associated with risky adolescent drinking. While parents' belief in the appropriateness of providing their child with alcohol may influence their provision behaviors, research into the factors associated with this belief is lacking.

OBJECTIVES

This study sought to identify the factors associated with parents' belief in the appropriateness of providing alcohol to their underage child.

METHODS

Western Australian parents of 12-17 year olds (n = 443) completed an online survey assessing their drinking habits, alcohol provision behaviors, alcohol-related beliefs and attitudes, their child's alcohol consumption, and demographics.

RESULTS

Nearly half (44%) the parents surveyed reported providing their underage child with alcohol. Parents of older children and parents who (i) did not believe in the harms and recommendations associated with alcohol use in youth, (ii) agreed with youth-related drinking myths, and (iii) reported more occasions of alcohol consumption by their child were more likely to believe that it was appropriate to provide alcohol to their underage child. Those who believed providing alcohol to their underage child was appropriate were in turn more likely to provide alcohol.

CONCLUSIONS

Interventions aiming to reduce parental provision of alcohol to children should focus on changing parents' beliefs that this is an appropriate harm minimization behavior. Belief change may be facilitated by the implementation of public education campaigns that increase parents' belief in the alcohol-related harms associated with youth drinking and debunk youth-related drinking myths.

Transition to drug co-use among adolescent cannabis users: The role of decision-making and mental health

BACKGROUND

Co-use of cannabis and drugs other than cannabis (DOTC) influences the risk of experiencing cannabis disorders. Accordingly, we explored whether speed of transition to drug co-use, the number of DOTC used, and/or being an experimental cannabis-only user, a regular cannabis-only user, or a regular cannabis user who co-uses DOTC (i.e., cannabis-plus user) were associated with decision-making (DM), mental health disorder symptoms, or cannabis use-related characteristics.

METHODS

We analyzed baseline data from a sub-sample of 266 adolescent (ages 14 to 16) cannabis users (CU) participating in an ongoing longitudinal study. Assessments included semi-structured interviews, self-report questionnaires, and measures of drug use, DM (measured via the Iowa Gambling Task), mental health disorders, and cannabis use-related problems.

RESULTS

Endorsing a larger number of mood disorders symptoms was associated with being a regular cannabis-plus user rather than a regular cannabis-only user (AOR = 1.08, C.I.95% 1.01, 1.15). Poorer DM was associated with a faster transition to co-use, such that for each one unit increase in DM performance, the years to onset of drug co-use increased by 1% (p = 0.032). Endorsing a larger number of cannabis use-related problems was positively associated with endorsing a larger number of DOTC used (p = 0.001).

CONCLUSIONS

This study provides new evidence on the process of drug co-use among CU. Specifically, mood disorder symptoms were associated with use of DOTC among regular CU. Furthermore, poorer DM was associated with a faster transition to drug co-use. Poorer DM and mood disorder symptoms may aggravate or accelerate the onset of adverse consequences among adolescent CU.

Heavy Chronic Ethanol Exposure From Adolescence to Adulthood Induces Cerebellar Neuronal Loss and Motor Function Damage in Female Rats

Over the last years, heavy ethanol consumption by teenagers/younger adults has increased considerably among females. However, few studies have addressed the long-term impact on brain structures’ morphology and function of chronic exposure to high ethanol doses from adolescence to adulthood in females. In line with this idea, in the current study we investigated whether heavy chronic ethanol exposure during adolescence to adulthood may induce motor impairments and morphological and cellular alterations in the cerebellum of female rats. Adolescent female Wistar rats (35 days old) were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) during 55 days by gavage. At 90 days of age, motor function of animals was assessed using open field (OF), pole, beam walking and rotarod tests. Following completion of behavioral tests, morphological and immunohistochemical analyses of the cerebellum were performed. Chronic ethanol exposure impaired significantly motor performance of female rats, inducing spontaneous locomotor activity deficits, bradykinesia, incoordination and motor learning disruption. Moreover, histological analysis revealed that ethanol exposure induced atrophy and neuronal loss in the cerebellum. These findings indicate that heavy ethanol exposure during adolescence is associated with long-lasting cerebellar degeneration and motor impairments in female rats.

Evaluation of a public education campaign to support parents to reduce adolescent alcohol use

INTRODUCTION AND AIMS

Mass media education campaigns targeting parents may influence parent factors that reduce adolescent drinking; however few such campaigns have been evaluated.

DESIGN AND METHODS

The Parents, Young People and Alcohol campaign included two phases of mass media advertising, Cogs and I See, to deliver consistent messages across multiple media channels. The campaign targeted Western Australian parents of 12-17 year olds with messages describing alcohol's effect on the developing brain and adolescent physical and mental health. The campaign reinforced the National Health and Medical Research Council (NHMRC) Guideline that for under 18s, not drinking is the safest option. Parent knowledge, attitudes and behaviours were assessed via cross-sectional surveys administered before the campaign (Time 1) and at two post-tests (Time 2; Time 3). Post-test campaign awareness and perceptions were also assessed.

RESULTS

Campaign awareness was high (48% Time 2; 80% Time 3) and over 86% of parents found the campaign believable and relevant at both post-tests. Increased knowledge of the NHMRC guideline and lower belief in alcohol myths were found at both post-tests compared to Time 1. Less positive attitudes to parental supply were found at Time 2, but were not sustained at Time 3. Parents were more likely to have discussed alcohol risks and limiting drinking with their child at Time 3, but parent-to-child alcohol supply did not change significantly.

DISCUSSION AND CONCLUSIONS

The campaign achieved high awareness and positively influenced parental outcomes. Longer term campaign implementation supported by policy and environmental measures may be required to change parental supply.

Neurocognitive and physical functioning in the Seveso Women's Health Study

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is neurotoxic in animals but few studies have investigated its effects on the human brain. Related dioxin-like compounds have been linked to poorer cognitive and motor function in older adults, with effects more pronounced in women, perhaps due to the loss of neuro-protective estrogen in menopause. On 10 July 1976, a chemical explosion in Seveso, Italy, resulted in one of the highest known residential exposures to TCDD. In 1996, we initiated the Seveso Women's Health Study, a retrospective cohort study of the health of the women who were newborn to 40 years old in 1976. Here, we investigate whether TCDD exposure is associated with physical functioning and working memory more than 20 years later. Individual TCDD concentration (ppt) was measured in archived serum collected soon after the explosion. In 1996 and 2008, we measured physical functioning (n=154) and working memory (n=459), respectively. We examined associations between serum TCDD and motor and cognitive outcomes with multivariate linear regression and semi-parametric estimators. A 10-fold increase in serum TCDD was not associated with walking speed (adjusted β=0.0006ft/s, 95% Confidence Interval (CI): -0.13, 0.13), upper body mobility (adjusted β=-0.06, 95% CI: -0.36, 0.23), or manual dexterity (adjusted β=0.34, 95% CI: -0.65, 1.33). We observed an inverted U-shaped association in grip strength, with poorer strength in the lowest and highest TCDD exposure levels. There was no association between TCDD and the Wechsler digit and spatial span tests. Neither menopause status at assessment nor developmental timing of exposure modified associations between TCDD and working memory. Our findings, in one of the only studies of TCDD's effects on neuropsychological and physical functioning in women, do not indicate an adverse effect on these domains, with the exception of a U-shaped relationship with grip strength. Given the limited assessment and relative youth of the women at this follow-up, future work examining additional neuropsychological outcomes is warranted.

Child-parent agreement on alcohol-related parenting: Opportunities for prevention of alcohol-related harm

ISSUE ADDRESSED

Excessive alcohol consumption places adolescents at increased risk of preventable, acute alcohol-related injury. Parental attitudes and behaviours influence adolescents' alcohol use. This study examined alignment in parent and child reports of alcohol-related parenting and whether misalignment related to the child ever having drunk alcohol.

METHODS

A cross-sectional online survey was conducted in five secondary schools in [information removed for blinding in Perth, Western Australia] in 2015. All students in Years 7, 10 and 12 and their parents were eligible, and data were matched for 124 child-parent dyads. Alignment of parent-child reports was assessed using kappa statistics. In dyads where the parent reported protective attitudes and behaviours, the association between misalignment and alcohol use was tested in logistic regressions.

RESULTS

Overall, child-parent reports were aligned on parents' expectations, knowledge and actions (65% and higher agreed). While alignment on parental expectations seemed to decrease with age, alignment on parental communication and rule-setting increased. Misalignment on reports of parents' expectations was associated with increased odds of the child reporting having ever had alcohol (OR = 5.5; 95% CI = 2.7-47.7), as was parental supply (OR = 20.2; 95% CI = 3.3-121.5), but misalignment on parental communication, rule-setting and knowledge were not.

CONCLUSIONS

Parent nonsupply of alcohol and disapproval of use were most important in terms of associations with ever drinking. SO WHAT?: These findings call for interventions that support parents to expect no alcohol use and enable parents to communicate their expectation in a manner that resonates with their child. Effective parenting will contribute to reducing alcohol-related harm in adolescents.

Effects of adolescent alcohol consumption on the brain and behaviour

Per occasion, alcohol consumption is higher in adolescents than in adults in both humans and laboratory animals, with changes in the adolescent brain probably contributing to this elevated drinking. This Review examines the contributors to and consequences of the use of alcohol in adolescents. Human adolescents with a history of alcohol use differ neurally and cognitively from other adolescents; some of these differences predate the commencement of alcohol consumption and serve as potential risk factors for later alcohol use, whereas others emerge from its use. The consequences of alcohol use in human adolescents include alterations in attention, verbal learning, visuospatial processing and memory, along with altered development of grey and white matter volumes and disrupted white matter integrity. The functional consequences of adolescent alcohol use emerging from studies of rodent models of adolescence include decreased cognitive flexibility, behavioural inefficiencies and elevations in anxiety, disinhibition, impulsivity and risk-taking. Rodent studies have also showed that adolescent alcohol use can impair neurogenesis, induce neuroinflammation and epigenetic alterations, and lead to the persistence of adolescent-like neurobehavioural phenotypes into adulthood. Although only a limited number of studies have examined comparable measures in humans and laboratory animals, the available data provide evidence for notable across-species similarities in the neural consequences of adolescent alcohol exposure, providing support for further translational efforts in this context.

Binge Alcohol Exposure Causes Neurobehavioral Deficits and GSK3β Activation in the Hippocampus of Adolescent Rats

Heavy alcohol exposure causes profound damage to the adolescent brain, particularly the hippocampus, which underlie some behavioral deficits. However, the underlying molecular mechanisms remain inconclusive. The current study sought to determine whether binge alcohol exposure affects the hippocampus-related behaviors and key signaling proteins that may mediate alcohol neurotoxicity in adolescent rats. Alcohol exposure reduced the number of both NeuN-positive and doublecortin-positive cells in the hippocampus. Alcohol also induced neurodegeneration which was confirmed by ultrastructural analysis by electronic microscopy and was accompanied with the activation of microglia. Binge alcohol exposure impaired spatial learning and memory which was evaluated by the Morris water maze. However, alcohol did not alter the spontaneous locomotor activity which was determined by the open field test. GSK3β is a multi-function serine/threonine protein kinase regulating both neuronal survival and neurogenesis and plays an important role in various neurodegenerative disorders. We have previously shown that GSK3β is a key mediator of alcohol-induced neuron apoptosis in the developing brain. We showed here binge alcohol exposure caused GSK3β activation by inducing dephosphorylation at Ser9 without affecting the phosphorylation of Tyr216 in the hippocampus. Thus, GSK3β may be involved in binge alcohol exposure-induced neuronal damage to the adolescent hippocampus.

Alcohol treatment goal choice predicts longitudinal drinking outcomes in adolescent substance users

Social cognitive theory suggests that when individuals select their own goals, they work harder to achieve them as compared to clinician-imposed goals. Moreover, achieving goals during the course of treatment may increase self-efficacy, which could positively predict outcome. Research in clinical samples of adults with alcohol use disorder supports the utility of treatment goal choice in predicting longitudinal outcomes; a total abstinence (TA) goal choice has been associated with better clinical outcomes (e.g. greater percentage of days abstinent, more days to relapse to heavy drinking) compared to a controlled use (CU) goal choice. Treatment of adolescents presents unique challenges, because adolescents tend to be resistant to treatment and often enter treatment in response to external pressures (e.g. parent, school system). Data from 110 adolescents aged 14 to 18 were collected upon admission to outpatient substance use disorder treatment. A series of hierarchical linear regressions was used to test the utility of the alcohol treatment goal choice variable in predicting drinking outcomes at 6-, 12-, and 24-month follow-ups. Separate models were run to examine binge drinking days, percentage of days abstinent, and drinks per drinking day at each time point. Goal choice significantly predicted drinking outcomes at the 12-month follow-up, but not at the 6- or 24-month time points, such that TA goal choice was associated with better clinical outcomes. These findings are relevant to treatment planning, as they suggest that goal choice may have clinical utility as a predictor of alcohol use disorder clinical course in adolescents.

Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis

Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children's cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM2.5) at residential locations affects intelligence quotient (IQ) during pre-/early- adolescence (ages 9-11) and emerging adulthood (ages 18-20) in a demographically-diverse population (N = 1,360) residing in Southern California. Increased ambient PM2.5 levels were associated with decreased IQ scores. This association was more evident for Performance IQ (PIQ), but less for Verbal IQ, assessed by the Wechsler Abbreviated Scale of Intelligence. For each inter-quartile (7.73 μg/m3) increase in one-year PM2.5 preceding each assessment, the average PIQ score decreased by 3.08 points (95% confidence interval = [-6.04, -0.12]) accounting for within-family/within-individual correlations, demographic characteristics, family socioeconomic status (SES), parents' cognitive abilities, neighborhood characteristics, and other spatial confounders. The adverse effect was 150% greater in low SES families and 89% stronger in males, compared to their counterparts. Better understanding of the social disparities and sexual dimorphism in the adverse PM2.5-IQ effects may help elucidate the underlying mechanisms and shed light on prevention strategies.

Voluntary alcohol intake after noise exposure in adolescent rats: Hippocampal-related behavioral alterations

Different physical or chemical agents, such as noise or alcohol, can induce diverse behavioral and biochemical alterations. Considering the high probability of young people to undergo consecutive or simultaneous exposures, the aim of the present work was to investigate in an animal model if noise exposure at early adolescence could induce hippocampal-related behavioral changes that might be modified after alcohol intake. Male Wistar rats (28-days-old) were exposed to noise (95-97 dB, 2 h). Afterwards, animals were allowed to voluntarily drink alcohol (10% ethanol in tap water) for three consecutive days, using the two-bottle free choice paradigm. After that, hippocampal-related memory and anxiety-like behavior tests were performed. Results show that whereas noise-exposed rats presented deficits in habituation memory, those who drank alcohol exhibited impairments in associative memory and anxiety-like behaviors. In contrast, exposure to noise followed by alcohol intake showed increases in exploratory and locomotor activities as well as in anxiety-like behaviors, unlike what was observed using each agent separately. Finally, lower levels of alcohol intake were measured in these animals when compared with those that drank alcohol and were not exposed to noise. Present findings demonstrate that exposure to physical and chemical challenges during early adolescence might induce behavioral alterations that could differ depending on the schedule used, suggesting a high vulnerability of rat developing brain to these socially relevant agents.

Problematic alcohol use and reduced hippocampal volume: a meta-analytic review

BACKGROUND

A number of studies reports reduced hippocampal volume in individuals who engage in problematic alcohol use. However, the magnitude of the difference in hippocampal volume between individuals with v. without problematic alcohol use has varied widely, and there have been null findings. Moreover, the studies comprise diverse alcohol use constructs and samples, including clinically significant alcohol use disorders and subclinical but problematic alcohol use (e.g. binge drinking), adults and adolescents, and males and females.

METHODS

We conducted the first quantitative synthesis of the published empirical research on associations between problematic alcohol use and hippocampal volume. In total, 23 studies were identified and selected for inclusion in the meta-analysis; effects sizes were aggregated using a random-effects model.

RESULTS

Problematic alcohol use was associated with significantly smaller hippocampal volume (d = -0.53). Moderator analyses indicated that effects were stronger for clinically significant v. subclinical alcohol use and among adults relative to adolescents; effects did not differ among males and females.

CONCLUSIONS

Problematic alcohol use is associated with reduced hippocampal volume. The moderate overall effect size suggests the need for larger samples than are typically included in studies of alcohol use and hippocampal volume. Because the existing literature is almost entirely cross-sectional, future research using causally informative study designs is needed to determine whether this association reflects premorbid risk for the development of problematic alcohol use and/or whether alcohol has a neurotoxic effect on the hippocampus.

Prenatal ethanol exposure modifies locomotor activity and induces selective changes in Met-enk expression in adolescent rats

Several studies suggest that prenatal ethanol exposure (PEE) facilitates ethanol intake. Opioid peptides play a main role in ethanol reinforcement during infancy and adulthood. However, PEE effects upon motor responsiveness elicited by an ethanol challenge and the participation of opioids in these actions remain to be understood. This work assessed the susceptibility of adolescent rats to prenatal and/or postnatal ethanol exposure in terms of behavioral responses, as well as alcohol effects on Met-enk expression in brain areas related to drug reinforcement. Motor parameters (horizontal locomotion, rearings and stereotyped behaviors) in pre- and postnatally ethanol-challenged adolescents were evaluated. Pregnant rats received ethanol (2g/kg) or water during gestational days 17-20. Adolescents at postnatal day 30 (PD30) were tested in a three-trial activity paradigm (habituation, vehicle and drug sessions). Met-enk content was quantitated by radioimmunoassay in several regions: ventral tegmental area [VTA], nucleus accumbens [NAcc], prefrontal cortex [PFC], substantia nigra [SN], caudate-putamen [CP], amygdala, hypothalamus and hippocampus. PEE significantly reduced rearing responses. Ethanol challenge at PD30 decreased horizontal locomotion and showed a tendency to reduce rearings and stereotyped behaviors. PEE increased Met-enk content in the PFC, CP, hypothalamus and hippocampus, but did not alter peptide levels in the amygdala, VTA and NAcc. These findings suggest that PEE selectively modifies behavioral parameters at PD30 and induces specific changes in Met-enk content in regions of the mesocortical and nigrostriatal pathways, the hypothalamus and hippocampus. Prenatal and postnatal ethanol actions on motor activity in adolescents could involve activation of specific neural enkephalinergic pathways.

Longitudinal influence of alcohol and marijuana use on academic performance in college students

BACKGROUND

Alcohol and marijuana are the two most abused substances in US colleges. However, research on the combined influence (cross sectional or longitudinal) of these substances on academic performance is currently scant.

METHODS

Data were derived from the longitudinal 2-year Brain and Alcohol Research in College Students (BARCS) study including 1142 freshman students who completed monthly marijuana use and alcohol consumption surveys. Subjects were classified into data-driven groups based on their alcohol and marijuana consumption. A linear mixed-model (LMM) was employed using this grouping factor to predict grade point average (GPA), adjusted for a variety of socio-demographic and clinical factors.

RESULTS

Three data-driven clusters emerged: 1) No/low users of both, 2) medium-high alcohol/no-low marijuana, and 3) medium-high users of both substances. Individual cluster derivations between consecutive semesters remained stable. No significant interaction between clusters and semester (time) was noted. Post-hoc analysis suggest that at the outset, compared to sober peers, students using moderate to high levels of alcohol and low marijuana demonstrate lower GPAs, but this difference becomes non-significant over time. In contrast, students consuming both substances at moderate-to-high levels score significantly lower at both the outset and across the 2-year investigation period. Our follow-up analysis also indicate that when students curtailed their substance use over time they had significantly higher academic GPA compared to those who remained stable in their substance use patterns over the two year period.

CONCLUSIONS

Overall, our study validates and extends the current literature by providing important implications of concurrent alcohol and marijuana use on academic achievement in college.

Examining the Impact of Alcohol and Other Drug Education Exposure on Student Alcohol Consumption

This investigation examined the association between alcohol and other drug (AOD) prevention/education programs and drinking behaviors among students aged 12 to 17 years. We conducted a secondary analysis of the 2013 National Survey on Drug Use and Health ( N = 17,736). AOD prevention/education was assessed in three school settings: special class, regular class, and outside regular class. Outcome variables included past year alcohol use and current heavy episodic drinking. Associations were assessed via one-way analyses of variance and multiple regression models. There was a significant effect of program exposure on alcohol use ( p<.001) and heavy episodic drinking ( p = .002). Regression results found AOD prevention/education exposure ( p = .004) was significant, indicating that exposure decreased past year use. No difference was found based on heavy episodic drinking. Increasing exposure to AOD prevention/education programs is warranted and encouraged.

Type 2 Neural Progenitor Cell Activation Drives Reactive Neurogenesis after Binge-Like Alcohol Exposure in Adolescent Male Rats

Excessive alcohol consumption during adolescence remains a significant health concern as alcohol drinking during adolescence increases the likelihood of an alcohol use disorder in adulthood by fourfold. Binge drinking in adolescence is a particular problem as binge-pattern consumption is the biggest predictor of neurodegeneration from alcohol and adolescents are particularly susceptible to the damaging effects of alcohol. The adolescent hippocampus, in particular, is highly susceptible to alcohol-induced structural and functional effects, including volume and neuron loss. However, hippocampal structure and function may recover with abstinence and, like in adults, a reactive burst in hippocampal neurogenesis in abstinence may contribute to that recovery. As the mechanism of this reactive neurogenesis is not known, the current study investigated potential mechanisms of reactive neurogenesis in binge alcohol exposure in adolescent, male rats. In a screen for cell cycle perturbation, a dramatic increase in the number of cells in all phases of the cycle was observed at 7 days following binge ethanol exposure as compared to controls. However, the proportion of cells in each phase was not different between ethanol-exposed rats and controls, indicating that cell cycle dynamics are not responsible for the reactive burst in neurogenesis. Instead, the marked increase in hippocampal proliferation was shown to be due to a twofold increase in proliferating progenitor cells, specifically an increase in cells colabeled with the progenitor cell marker Sox2 and S-phase (proliferation) marker, BrdU, in ethanol-exposed rats. To further characterize the individual subtypes of neural progenitor cells (NPCs) affected by adolescent binge ethanol exposure, a fluorescent quadruple labeling technique was utilized to differentiate type 1, 2a, 2b, and 3 progenitor cells simultaneously. At one week into abstinence, animals in the ethanol exposure groups had an increase in proliferating type 2 (intermediate progenitors) and type 3 (neuroblast) progenitors but not type 1 neural stem cells. These results together suggest that activation of type 2 NPCs out of quiescence is likely the primary mechanism for reactive hippocampal neurogenesis following adolescent alcohol exposure.

Parental solicitation, parental control, child disclosure, and substance use: native and immigrant Dutch adolescents

OBJECTIVES

The present study examined whether the relation of parental solicitation, parental control, and child disclosure with adolescent alcohol and cannabis use is similar for native and non-Western immigrant Dutch adolescents.

DESIGN

Questionnaire data from two study-samples were used with a combined sample of 705 adolescents (mean age 16.2 years; 47.2% female; 25.2% non-Western immigrant background).

RESULTS

Native Dutch adolescents reported more weekly alcohol use than immigrant adolescents, while rates of cannabis use by native and immigrant adolescents were similar. Immigrant females reported lower levels of parental solicitation and child disclosure, but higher levels of parental control than native females. There were no differences in the sources of parental knowledge between native and immigrant males. Regression analyses showed no significant interaction effects of parental solicitation, parental control, or child disclosure with ethnic background for both alcohol and cannabis use (all p values > .05).

CONCLUSION

Despite mean level differences in various factors, we did not find evidence of an interaction effect of the sources of parental knowledge with ethnic background on alcohol and cannabis use. This suggests that theories and prevention strategies focusing on these sources of parental knowledge in relation to substance use can be applicable to both native and immigrant Dutch adolescents.

Long-Lasting Effects of Chronic Intermittent Alcohol Exposure in Adolescent Mice on Object Recognition and Hippocampal Neuronal Activity

BACKGROUND

Binge drinking is popular and highly prevalent in teenagers. However, the long-term cognitive and neurobiological consequences of such practices are not yet fully understood. In this context, we therefore assessed in mice whether a chronic intermittent alcohol (CIA) exposure in adolescence had long-term consequences on object discrimination and memory performances, emotional behaviors, brain activity, and morphology.

METHODS

C57BL/6JRj mice were treated with either saline or ethanol (EtOH) (2 g/kg/d, i.p., from postnatal days [PND] 30 to PND 44 every other day). The day following the last administration or later in adulthood (PND 71) mice were tested for different behavioral tests (novel object recognition, spontaneous alternation, light-dark box, elevated plus-maze, actimeter test), to assess object recognition, working memory performances, anxiety-like behavior, and locomotor activity. We also investigated neuronal activation of hippocampus, prefrontal and perirhinal cortices, and anatomical changes using immediate-early gene expression and longitudinal brain magnetic resonance imaging.

RESULTS

Our results showed that adolescent mice exposed to CIA present a critical and persistent impairment of short-term object recognition performances. By contrast, spatial working memory was not impaired, nor was anxiety-like behavior. This altered object discrimination was associated with a biphasic change in neuronal activity in the hippocampus but without morphological changes. Indeed, c-Fos expression was specifically increased in the dorsal dentate gyrus (DG) of the hippocampus after the binge exposure, but then became significantly lower in adulthood both in the DG and the CA1 part of the hippocampus compared with adult saline pretreated mice.

CONCLUSIONS

These findings provide evidence for adolescent vulnerability to the effects of intermittent binge EtOH exposure on object discrimination and hippocampal activity with long-lasting consequences.

Do Juvenile Curfew Laws Reduce Underage Drinking?

OBJECTIVE

Although not originally enacted to deter the problem of underage drinking in the United States, one set of laws that may influence this behavior is juvenile curfew laws. This research asked the following: (a) What is the effect of enacting a juvenile curfew law on youth drinking, and (b) do demographic variables moderate the relation between juvenile curfew law enactment and drinking? This study examined the effect of juvenile curfew laws on underage drinking, using data from 46 U.S. cities from 1991 to 2005.

METHOD

In 2014, we compiled a data set containing alcohol and curfew law data by zip code. It included 63,081 minors (ages 12-17 years) from 1,081 zip codes. We used difference-in-difference regressions to analyze the data.

RESULTS

The effect of the enactment of a curfew law on the likelihood of consuming alcohol in the past year or past 30 days or of heavy episodic drinking in the past 2 weeks was not significant when compared with cities without curfew laws during the same periods. Although the likelihood of consuming alcohol over the past year differed depending on an individual's characteristics (e.g., race/ethnicity, age, and gender), none of the interaction terms between these characteristics and curfew laws were significant.

CONCLUSIONS

Curfew laws appear to have a nonsignificant effect on youth drinking, but these results are unclear without more knowledge as to where and when youth are drinking both before and after the enactment of curfew laws and how these laws are being enforced.

Predicting High School Minority Adolescents' Drinking from Their Exposure to White Schoolmates: Differences and Similarities among Hispanic, Black, and Asian U.S. Adolescents

White students' drinking may constitute a risk factor for drinking among same-school minority adolescents. Our study examined data from 14,986 ethnic minority American high school students (56% female, mean age = 15.6). Models examined associations between school-level White student drinking and same-school Black, Hispanic, and Asian adolescents' drinking, as well as whether schools' proportions of White students and friendships with White schoolmates moderated these associations. Both school-level White students' drinking and minority students' friendships with White schoolmates were associated with levels of minority student drinking. But these associations were dependent upon levels of other study variables. In particular, there were higher associations between school-level risk factors and minorities' drinking when minority adolescents had high proportions of Whites among their friends.

Two Binges of Ethanol a Day Keep the Memory Away in Adolescent Rats: Key Role for GLUN2B Subunit

BACKGROUND

Binge drinking is common in adolescents, but the impact of only a few binges on learning and memory appears underestimated. Many studies have tested the effects of long and intermittent ethanol exposure on long-term synaptic potentiation, and whether long-term synaptic depression is affected remains unknown.

METHODS

We studied the effects of one (3 g/kg, i.p.; blood ethanol content of 197.5±19 mg/dL) or 2 alcohol intoxications (given 9 hours apart) on adolescent rat's memory and synaptic plasticity in hippocampus slice after different delay.

RESULTS

Animals treated with 2 ethanol intoxications 48 hours before training phase in the novel object recognition task failed during test phase. As learning is related to NMDA-dependent mechanisms, we tested ketamine and found the same effect as ethanol, whereas D-serine prevented learning deficit. In hippocampus slice, NMDA-dependent long-term synaptic depression was abolished 48 hours after ethanol or ketamine but prevented after D-serine or in a low-Mg(2+) recording medium. Long-term synaptic depression abolition was not observed 8 days after treatment. An i.p. treatment with MK-801, tetrahydroisoxazolopyridine, or muscimol was ineffective, and long-term synaptic potentiation, intrinsic excitability, and glutamate release remained unaffected. The input/ouput curve for NMDA-fEPSPs was shifted to the left 48 hours after the binges with a stronger contribution of GluN2B subunit, leading to a leftward shift of the Bienenstock-Cooper-Munro relationship. Interestingly, there were no cellular effects after only one ethanol injection.

CONCLUSION

Two ethanol "binges" in adolescent rats are sufficient to reversibly abolish long-term synaptic depression and to evoke cognitive deficits via a short-lasting, repeated blockade of NMDA receptors only, inducing a change in the receptor subunit composition. Furthermore, ethanol effects developed over a 48-hour period of abstinence, indicating an important role of intermittence during a repeated long-duration binge behavior.

Chronic ethanol exposure during adolescence through early adulthood in female rats induces emotional and memory deficits associated with morphological and molecular alterations in hippocampus

There is increasing evidence that heavy ethanol exposure in early life may produce long-lasting neurobehavioral consequences, since brain structural maturation continues until adolescence. It is well established that females are more susceptible to alcohol-induced neurotoxicity and that ethanol consumption is increasing among women, especially during adolescence. In the present study, we investigated whether chronic ethanol exposure during adolescence through early adulthood in female rats may induce hippocampal histological damage and neurobehavioral impairments. Female rats were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) by gavage from the 35(th)-90(th) day of life. Ethanol-exposed animals displayed reduced exploration of the central area and increased number of fecal boluses in the open field test indicative of anxiogenic responses. Moreover, chronic high ethanol exposure during adolescence induced marked impairments on short-term memory of female rats addressed on social recognition and step-down inhibitory avoidance tasks. These neurobehavioral deficits induced by ethanol exposure during adolescence through early adulthood were accompanied by the reduction of hippocampal formation volume as well as the loss of neurons, astrocytes and microglia cells in the hippocampus. These results indicate that chronic high ethanol exposure during adolescence through early adulthood in female rats induces long-lasting emotional and memory deficits associated with morphological and molecular alterations in the hippocampus.

Effects of age and acute ethanol on glutamatergic neurotransmission in the medial prefrontal cortex of freely moving rats using enzyme-based microelectrode amperometry

Ethanol abuse during adolescence may significantly alter development of the prefrontal cortex which continues to undergo structural remodeling into adulthood. Glutamatergic neurotransmission plays an important role during these brain maturation processes and is modulated by ethanol. In this study, we investigated glutamate dynamics in the medial prefrontal cortex of freely moving rats, using enzyme-based microelectrode amperometry. We analyzed the effects of an intraperitoneal ethanol injection (1 g/kg) on cortical glutamate levels in adolescent and adult rats. Notably, basal glutamate levels decreased with age and these levels were found to be significantly different between postnatal day (PND) 28-38 vs PND 44-55 (p<0.05) and PND 28-38 vs adult animals (p<0.001). We also observed spontaneous glutamate release (transients) throughout the recordings. The frequency of transients (per hour) was significantly higher in adolescent rats (PND 28-38 and PND 44-55) compared to those of adults. In adolescent rats, post-ethanol injection, the frequency of glutamate transients decreased within the first hour (p<0.05), it recovered slowly and in the third hour there was a significant rebound increase of the frequency (p<0.05). Our data demonstrate age-dependent differences in extracellular glutamate levels in the medial prefrontal cortex and suggest that acute ethanol injections have both inhibitory and excitatory effects in adolescent rats. These effects of ethanol on the prefrontal cortex may disturb its maturation and possibly limiting individuals´ control over addictive behaviors.

Providing alcohol for underage youth: what messages should we be sending parents?

OBJECTIVE

There have been conflicting findings in the literature concerning the risks to adolescents when parents provide them with alcohol. Studies have examined various ways in which parents directly affect adolescent alcohol consumption through provision (e.g., parental offers, parental allowance/supervision, parental presence while drinking, and parental supply). This review synthesizes findings on the direct ways parental provision can influence a child's alcohol consumption and related problems in an effort to provide parents with science-based guidance. We describe potential mechanisms of the relationship between these parental influences and adolescent problems, suggest future directions for research, and discuss implications for parents.

METHOD

Twenty-two studies (a mix of cross-sectional and longitudinal) that empirically examined the association between parental provision and adolescent drinking outcomes were reviewed.

RESULTS

Parental provision was generally associated with increased adolescent alcohol use and, in some instances, increased heavy episodic drinking as well as higher rates of alcohol-related problems. Data in support of the view that parental provision serves as a protective factor in the face of other risk factors were equivocal.

CONCLUSIONS

The nature and extent of the risks associated with parental provision, and the potential mechanisms underlying this association, are complex issues. Although more rigorous studies with longitudinal designs are needed, parents should be aware of potential risks associated with providing adolescents with alcohol and a place to drink. It is recommended that parents discourage drinking until adolescents reach legal age.

Evolution of the binge drinking pattern in college students: neurophysiological correlates

It is well known that alcohol impairs response inhibition and that adolescence is a critical period of neuromaturation where cognitive processes such as inhibitory control are still developing. In recent years, growing evidence has shown the negative consequences of alcohol binge drinking on the adolescent and young human brain. However, the effects of cessation of binge drinking on brain function remain unexplored. The objective of the present study was to examine brain activity during response execution and inhibition in young binge drinkers in relation to the progression of their drinking habits over time. Event-related potentials (ERPs) elicited by a Go/NoGo task were recorded twice within a 2-year interval in 57 undergraduate students (25 controls, 22 binge drinkers, and 10 ex-binge drinkers) with no personal or family history of alcoholism or psychopathological disorders. The results showed that the amplitude of NoGo-P3 over the frontal region correlated with an earlier age of onset of regular drinking as well as with greater quantity and speed of alcohol consumption. Regression analysis showed that NoGo-P3 amplitude was significantly predicted by the speed of alcohol intake and the age of onset of regular drinking. The group comparisons showed that, after maintaining a binge drinking pattern for at least 2 years, binge drinkers displayed significantly larger NoGo-P3 amplitudes than controls, whereas ex-binge drinkers were in an intermediate position between the two other groups (with no significant differences with respect to controls or binge drinkers). These findings suggest that binge drinking in young people may impair the neural functioning related to inhibitory processes, and that the cessation of binge drinking may act as a brake on the neurophysiological impairments related to response inhibition.

Brain structural and functional changes in adolescents with psychiatric disorders

During adolescence, hormonal and neurodevelopmental changes geared to ensuring reproduction and achieving independence are very likely mediated by the growth of neural processes, remodeling of synaptic connections, increased myelination in prefrontal areas and maturation of connecting subcortical areas. These processes, greatly accelerated in adolescence, follow an asynchronous pattern in different brain areas. Neuroimaging research using functional and structural magnetic resonance imaging has produced most of the insights regarding brain structural and functional neuropathology in adolescent psychiatric disorders. In schizophrenia, first episodes during adolescence are linked to greater-than-normal losses in gray matter density and white matter integrity and show a divergence of maturational trajectories from normative neural development in a progression similar to that of adult-onset schizophrenia. Anxiety and mood disorders in adolescence have been linked to abnormally increased activity in the amygdala and ventral prefrontal cortical areas, although some data suggest that neural abnormalities in the amygdala and anxiety maybe particularly more frequent in adolescents than in adults. Alcohol misuse in adolescence results in reduced integrity in the white matter and reduced gray matter density that, given the high intensity of adolescent synaptic and myelin remodeling, may result in persistent and profound changes in circuits supporting memory and emotional and appetitive control. The interaction of persistent changes due to prenatal exposure with the contemporaneous expression of genetic factors and disturbing environmental exposure may be an important factor in the appearance of psychiatric disorders in adolescence. Further progress in understanding adolescent psychopathology will require postmortem research of molecular and cellular determinants in the adolescent brain.

Reduction of adolescent alcohol use through family-school intervention: a randomized trial

PURPOSE

Two-year longitudinal follow-up data evaluated the behavioral impact of Resilient Families, a universal intervention that aimed to prevent early initiation and frequent and heavy adolescent alcohol use in secondary schools in Melbourne, Australia.

METHODS

Of 24 secondary schools (62% of those approached), 12 were randomly assigned to intervention and 12 as controls. Intervention students received a social relationship curriculum; their parents received parent education handbooks and invitations to parent education events outlining strategies to encourage healthy adolescent development and reduce adolescent alcohol misuse. At Wave 1 (2004), students were in Year 7 secondary school (mean age, 12.3 years). Data were imputed for students completing at least two of three annual surveys (N = 2,354). Wave 3 (2006; mean, 14.5 years) main outcome measures for alcohol use were "any," "frequent" (at least monthly), and "heavy" (five or more drinks in a session at least once in the prior fortnight). Multivariate logistic regression assessed intervention exposure effects, adjusting for school classroom clustering and baseline measures.

RESULTS

Relative to controls, intervention students showed significant reductions in any lifetime use (adjusted odds ratio [AOR], .78; 95% confidence interval [CI], .62-.97), and reduced progression to frequent (AOR, .69; CI, .56-.86) and heavy use (AOR, .75; CI, .60-.94).

CONCLUSIONS

Randomized assignment to Resilient Families was associated with a significant reduction in adolescent alcohol use among families volunteering for the evaluation. Family-school-based interventions appear promising as a strategy to contribute to population reductions in currently high rates of adolescent alcohol misuse.

Effects of acute or chronic ethanol exposure during adolescence on behavioral inhibition and efficiency in a modified water maze task

Ethanol is well known to adversely affect frontal executive functioning, which continues to develop throughout adolescence and into young adulthood. This is also a developmental window in which ethanol is misused by a significant number of adolescents. We examined the effects of acute and chronic ethanol exposure during adolescence on behavioral inhibition and efficiency using a modified water maze task. During acquisition, rats were trained to find a stable visible platform onto which they could escape. During the test phase, the stable platform was converted to a visible floating platform (providing no escape) and a new hidden platform was added in the opposite quadrant. The hidden platform was the only means of escape during the test phase. In experiment 1, adolescent animals received ethanol (1.0g/kg) 30min before each session during the test phase. In experiment 2, adolescent animals received chronic intermittent ethanol (5.0g/kg) for 16 days (PND30 To PND46) prior to any training in the maze. At PND72, training was initiated in the same modified water maze task. Results from experiment 1 indicated that acute ethanol promoted behavioral disinhibition and inefficiency. Experiment 2 showed that chronic intermittent ethanol during adolescence appeared to have no lasting effect on behavioral disinhibition or new spatial learning during adulthood. However, chronic ethanol did promote behavioral inefficiency. In summary, results indicate that ethanol-induced promotion of perseverative behavior may contribute to the many adverse behavioral sequelae of alcohol intoxication in adolescents and young adults. Moreover, the long-term effect of adolescent chronic ethanol exposure on behavioral efficiency is similar to that observed after chronic exposure in humans.

Are we drunk yet? Motor versus cognitive cues of subjective intoxication

BACKGROUND

Perception of alcohol intoxication presumably plays an important role in guiding behavior during a current drinking episode. Yet, there has been surprisingly little investigation of what aspects associated with intoxication are used by individuals to attribute their level of intoxication.

METHODS

Building on recent laboratory-based findings, this study employed a complex field-based design to explore the relative contributions of motor performance versus cognitive performance-specifically executive control-on self-attributions of intoxication. Individuals recruited outside of bars (N = 280; mean age = 22; range: 18 to 32) completed a structured interview, self-report questionnaire, and neuropsychological testing battery, and provided a breath alcohol concentration (BrAC) sample.

RESULTS

Results of a multiple linear regression analysis demonstrated that current level of subjective intoxication was associated with current alcohol-related stimulant effects, current sedative effects, and current BrAC. After controlling for the unique variance accounted for by these factors, subjective intoxication was better predicted by simple motor speed, as indexed by performance on the Finger Tapping Test, than by executive control, as indexed by performance on the Trail Making Test.

CONCLUSIONS

These results-generated from data collected in a naturally occurring setting-support previous findings from a more traditional laboratory-based investigation, thus illustrating the iterative process of linking field methodology and controlled laboratory experimentation.

Chronic binge-like alcohol consumption in adolescence causes depression-like symptoms possibly mediated by the effects of BDNF on neurogenesis

Here we investigated whether changes in neurogenesis and brain-derived neurotrophic factor (BDNF) expression are possible mechanisms involved in the depression-like symptom during the withdrawal/abstinence period after chronic binge-pattern alcohol consumption given the limited number of studies addressing the link between these factors in the adolescent brain. Forty-seven male Sprague-Dawley rats were used in the study and the experimental protocol started when rats were 25-days old. Rats were assigned to either: (a) ethanol or (b) control group. Animals in each group were further randomized to receive either: BDNF receptor agonist or vehicle. Rats were trained to self-administer ethanol and the binge protocol consisted of daily 30-min experimental sessions 4h into the dark period for 12days. Two days after the last drinking session, rats were tested in the sucrose preference test to evaluate anhedonia and the open field test after habituation to evaluate behavioral despair. Our data showed that: (1) self-administration of alcohol in a binge-like pattern causes inebriation as defined by the National Institute on Alcohol Abuse and Alcoholism and this pattern of alcohol exposure is associated with the development of a depression-like symptom; (2) no significant difference in blood alcohol levels between the two ethanol groups; and (3) chronic binge drinking resulted in the development of a depressive phenotype, decreased survival and neuronal differentiation of neural progenitor cells in the hippocampus, and decreased BDNF effect during the withdrawal period. But the most important finding in our study is that augmenting BDNF actions through the use of tyrosine kinase B (TrkB, a BDNF receptor) agonist restored neurogenesis and abolished the alcohol-induced anhedonia and despair behaviors seen during the withdrawal/abstinence period. Our results suggest that BDNF might be a molecule that can be targeted for interventions in alcoholism-depression co-incidence.

Age differences in fear retention and extinction in male Sprague-Dawley rats: effects of ethanol challenge during conditioning

Pavlovian fear conditioning is an ideal model to investigate how learning and memory are influenced by alcohol use during adolescence because the neural mechanisms involved have been studied extensively. In Exp 1, adolescent and adult male Sprague-Dawley rats were non-injected or injected with saline, 1 or 1.5 g/kg ethanol intraperitoneally 10 min prior to tone or context conditioning. Twenty-four hours later, animals were tested for tone or context retention and extinction, with examination of extinction retention conducted 24h thereafter. In Exp 2, a context extinction session was inserted between the tone conditioning and the tone fear retention/extinction days to reduce pre-CS baseline freezing levels at test. Basal levels of acquisition, fear retention, extinction, and extinction retention after tone conditioning were similar between adolescent and adult rats. In contrast adolescents showed faster context extinction than adults, while again not differing from adults during context acquisition, retention or extinction retention. In terms of ethanol effects, adolescents were less sensitive to ethanol-induced context retention deficits than adults. No age differences emerged in terms of tone fear retention, with ethanol disrupting tone fear retention at both ages in Exp 1, but at neither age in Exp 2, a difference seemingly due to group differences in pre-CS freezing during tone testing in Exp 1, but not Exp 2. These results suggest that age differences in the acute effects of ethanol on cognitive function are task-specific, and provide further evidence for age differences cognitive functioning in a task thought to be hippocampally related.

Age-dependent time courses of recovery for motor functions following acute toluene intoxication in rats

Toluene is a psychoactive chemical found in many household products including adhesives and thinners. Inhalation of these vapors can cause euphoria and impairments in motor control and neurological functioning. Misuse and abuse of toluene is most common in children, which may in part be due to an age-dependent neurobehavioral sensitivity to toluene. Here we assessed the effects of acute binge-like toluene inhalations (15 or 30 min; ∼5,000 ppm) on tasks that examine locomotion, exploration, balance, gait, and neurological functioning for adolescent (1 month), young adult (2-3 months), adult (5-6 months), and older adult (10-12 months) rats. Both motor and neurological functions were impaired following acute toluene inhalation at all ages. However, only the duration to recover from deficits in motor functions differed among age groups, with adolescent and young adult rats requiring notably longer recovery times than older rats. Our results are suggestive of an age-dependent vulnerability to the intoxicating effects of toluene.

Effects of a persistent binge drinking pattern of alcohol consumption in young people: a follow-up study using event-related potentials

AIMS

The objective of this study was to examine brain activity related to visual attention processes in youths who had maintained a binge drinking (BD) pattern of alcohol consumption for >2 years.

METHODS

The participants were 57 university students (26 binge drinkers: BDs) with no personal or family history of alcoholism or psychopathological disorders in first-degree relatives. Event-related potentials (ERPs) were recorded while participants performed a visual oddball task (twice within a 2-year interval). The latency and amplitude of the P3b component of the ERPs were analysed.

RESULTS

The P3b amplitude was larger in young BDs than in aged-matched controls at both evaluation times, and the difference was more pronounced after 2 years of maintenance of a BD pattern of consumption. The larger P3b amplitude was associated with an earlier onset of regular drinking and with a greater quantity and intensity of consumption.

CONCLUSIONS

These findings suggest that young BDs exhibit anomalies in neural activity involved in attentional/working memory processes, which increase after 2 years of maintenance of BD. This anomalous neural activity may reflect underlying dysfunctions in neurophysiological mechanisms as well as the recruitment of additional attentional/working memory resources to enable the binge drinkers to perform the task adequately.

ADOLESCENTS AND ALCOHOL

The high levels of alcohol consumption characteristic of adolescence may be in part biologically based, given that elevated consumption levels are also evident during this developmental transition in other mammalian species as well. Studies conducted using a simple animal model of adolescence in the rat has shown adolescents to be more sensitive than adults to social facilitatory and rewarding effects of alcohol, but less sensitive to numerous alcohol effects that may serve as cues to limit intake. These age-specific alcohol sensitivities appear related to differential rates of development of neural systems underlying different alcohol effects as well as to an ontogenetic decline in rapid brain compensations to alcohol, termed "acute tolerance". In contrast, these adolescent-typical sensitivities to alcohol do not appear to be notably influenced by pubertally-related increases in gonadal hormones. Although data are sparse, there are hints that similar alcohol sensitivities may also be seen in human adolescents, with this developmentally decreased sensitivity to alcohol's intoxicating effects possibly exacerbated by genetic vulnerabilities also characterized by an insensitivity to alcohol intoxication, thereby perhaps permitting especially high levels of alcohol consumption among vulnerable youth.