Adolescence: Booze, Brains, and Behavior

Association between adolescent alcohol use and cognitive function in young adulthood: A co-twin comparison study

BACKGROUND AND AIMS

Studies on adolescent alcohol use and cognition are often unable to separate the potential causal effects of alcohol use on cognition from shared etiological influences, including genetic influences or other substance use comorbidities also known to be associated with cognition, such as nicotine use. The present study aimed to fill this gap and clarify the relationship between adolescent alcohol use and young adult cognition by accounting for both measured and unmeasured confounders.

DESIGN

A random effects model accounting for nesting in families was used to control for measured confounders. Next, co-twin comparisons were conducted within the full sample and in monozygotic twin pairs (MZ) to control for unmeasured genetic and environmental confounders shared by co-twins.

PARTICIPANTS/SETTING

Participants were 812 individuals (58.6% female, 361 complete pairs, 146 MZ pairs) from the longitudinal FinnTwin12 study in Finland.

MEASUREMENTS

Adolescent alcohol use was indexed with measures of frequency of use and intoxication averaged across ages 14 and 17. Cognitive outcomes were measured at average age 22 and included Trail Making Test, California Stroop test, Wechsler Adult Intelligence subtests (Vocabulary, Block Design, Digit Symbol), Digit Span subtest of Wechsler Memory Scale, Mental Rotation Test and Object Location Memory test. Covariates included sex, parental education, general cognitive ability, current alcohol use and nicotine use.

FINDINGS

Greater frequency of alcohol use and frequency of intoxication across adolescence was associated with decreased vocabulary scores in the co-twin control [freq: stnd beta = -0.12, 95% confidence interval (CI) = -0.234, -0.013] and MZ only co-twin control models (freq: stnd beta = -0.305, 95% CI = -0.523, -0.087; intox: stnd beta = -0.301, 95% CI = -0.528, -0.074).

CONCLUSIONS

In Finland, there appears to be little evidence that adolescent alcohol use causes cognitive deficits in young adulthood, except modest evidence for association of higher adolescent alcohol use with lower young adult vocabulary scores.

Multi-level prediction of substance use: Interaction of white matter integrity, resting-state connectivity and inhibitory control measured repeatedly in every-day life

Substance use disorders are characterized by inhibition deficits related to disrupted connectivity in white matter pathways, leading via interaction to difficulties in resisting substance use. By combining neuroimaging with smartphone-based ecological momentary assessment (EMA), we questioned how biomarkers moderate inhibition deficits to predict use. Thus, we aimed to assess white matter integrity interaction with everyday inhibition deficits and related resting-state network connectivity to identify multi-dimensional predictors of substance use. Thirty-eight patients treated for alcohol, cannabis or tobacco use disorder completed 1 week of EMA to report substance use five times and complete Stroop inhibition testing twice daily. Before EMA tracking, participants underwent resting state functional MRI and diffusion tensor imaging (DTI) scanning. Regression analyses were conducted between mean Stroop performances and whole-brain fractional anisotropy (FA) in white matter. Moderation testing was conducted between mean FA within significant clusters as moderator and the link between momentary Stroop performance and use as outcome. Predictions between FA and resting-state connectivity strength in known inhibition-related networks were assessed using mixed modelling. Higher FA values in the anterior corpus callosum and bilateral anterior corona radiata predicted higher mean Stroop performance during the EMA week and stronger functional connectivity in occipital-frontal-cerebellar regions. Integrity in these regions moderated the link between inhibitory control and substance use, whereby stronger inhibition was predictive of the lowest probability of use for the highest FA values. In conclusion, compromised white matter structural integrity in anterior brain systems appears to underlie impairment in inhibitory control functional networks and compromised ability to refrain from substance use.

Cannabis Use and Parenting Practices among Young People: The Impact of Parenting Styles, Parental Cannabis-Specific Rules, and Parental Cannabis Use

Cannabis is the most commonly used illicit drug. Its use typically starts in adolescence, and parents play a key role in young people’s cannabis use. Our study aimed to examine and compare the effects of parenting styles, parental cannabis-specific rules, and parental cannabis use on young people’s cannabis use. The research sample consisted of 839 students from various secondary education programs in Slovenia, aged 14 to 21. Associations between the young people’s lifetime cannabis use and their experience of parenting practices were assessed using logistic regression, with demographic, socioeconomic, educational, health, and risk behaviors controlled in a multivariate model. Maternal authoritative parenting (in comparison with permissive parenting), strict maternal, cannabis-specific rules, and parental cannabis non-use statistically significantly reduced the likelihood of young people’s cannabis use. Its strongest predictor was parental cannabis use, followed by the mother’s specific cannabis-use rules and maternal parenting style. The findings of our study can contribute to the development of public health policies to more effectively prevent cannabis use among adolescents and emerging adults, including by designing prevention programs aimed at strengthening parents’ general and cannabis-specific practices and competences.

Structural differences in adolescent brains can predict alcohol misuse

Alcohol misuse during adolescence (AAM) has been associated with disruptive development of adolescent brains. In this longitudinal machine learning (ML) study, we could predict AAM significantly from brain structure (T1-weighted imaging and DTI) with accuracies of 73 -78% in the IMAGEN dataset (n∼1182). Our results not only show that structural differences in brain can predict AAM, but also suggests that such differences might precede AAM behavior in the data. We predicted 10 phenotypes of AAM at age 22 using brain MRI features at ages 14, 19, and 22. Binge drinking was found to be the most predictable phenotype. The most informative brain features were located in the ventricular CSF, and in white matter tracts of the corpus callosum, internal capsule, and brain stem. In the cortex, they were spread across the occipital, frontal, and temporal lobes and in the cingulate cortex. We also experimented with four different ML models and several confound control techniques. Support Vector Machine (SVM) with rbf kernel and Gradient Boosting consistently performed better than the linear models, linear SVM and Logistic Regression. Our study also demonstrates how the choice of the predicted phenotype, ML model, and confound correction technique are all crucial decisions in an explorative ML study analyzing psychiatric disorders with small effect sizes such as AAM.

The Link Between Cannabis Use and Violent Behavior in the Early Phase of Psychosis: The Potential Role of Impulsivity

INTRODUCTION

Recently, the literature has shown that Cannabis Use (CU) was a risk factor for Violent Behavior (VB) in patients with psychosis, and those in the early phase of psychosis (EPP). These findings are relevant because of the high prevalence of CU in this EPP, and the potential for prevention during this phase of illness. However, there is still a lack of clear explanations, supported by empirical evidence, about what underlies the link between CU and VB against other.

METHOD

This viewpoint reviews the scientific literature on the link between CU and VB, and the involvement of impulsivity in this relationship. This last point will be addressed at clinical and neurobiological levels.

RESULTS

Recent studies confirmed that CU is particularly high in the EPP, and is a risk factor for VB in the EPP and schizophrenia. Studies have also shown that impulsivity is a risk factor for VB in psychosis, is associated with CU, and may mediate the link between CU and VB. Research suggests a neurobiological mechanism, as CU affects the structures and function of frontal areas, known to play a role in impulsive behavior.

CONCLUSION

Scientific evidence support the hypothesis of an involvement of impulsivity as a variable that could mediate the link between CU and aggression, particularly, when CU has an early onset. However, this hypothesis should be confirmed with longitudinal studies and by taking into account confounding factors. The studies highlight the relevance of early prevention in the EPP, in addition to interventions focusing on psychotic disorders.

Consequences of adolescent alcohol use on adult hippocampal neurogenesis and hippocampal integrity

Alcohol is the most commonly used drug among adolescents. Their decreased sensitivity to self-regulating cues to stop drinking coincides with an enhanced vulnerability to negative outcomes of excessive drinking. In adolescents, the hippocampus is one brain region that is particularly susceptible to alcohol-induced neurodegeneration. While cell death is causal, alcohol effects on adult neurogenesis also impact hippocampal structure and function. This review describes what little is known about adolescent-specific effects of alcohol on adult neurogenesis and its relationship to hippocampal integrity. For example, alcohol intoxication inhibits neurogenesis persistently in adolescents but produces aberrant neurogenesis after alcohol dependence. Little is known, however, about the role of adolescent-born neurons in hippocampal integrity or the mechanisms of these effects. Understanding the role of neurogenesis in adolescent alcohol use and misuse is critical to our understanding of adolescent susceptibility to alcohol pathology and increased likelihood of developing alcohol problems in adulthood.

The association between reinforcement sensitivity and substance use is mediated by individual differences in dispositional affectivity in adolescents

BACKGROUND

Adolescence marks the onset of substance use experimentation and adolescents are particularly vulnerable to certain negative effects of substances. Some evidence indicates reinforcement sensitivity is associated with substance use, though little is known about mechanisms underlying such association.

AIMS

in the current study were to examine, (1) associations between behavioral activation (BAS) and behavioral inhibition (BIS) system sensitivity, positive (PA) and negative affectivity (NA), and alcohol use and alcohol problems as well as tobacco, and marijuana use, and whether (2) associations are mediated by PA or NA.

METHODS

Participants were a community sample of N = 125 adolescents (M_age = 15.67 years; SD = 0.93; 52% boys) who completed self-report measures.

RESULTS

evinced associations, generally as expected, across variables (all ps < 0.05). In mediation analyses, an association emerged between BIS sensitivity and alcohol use, mediated by NA (95%CIs [0.034; 0.390]); greater BIS sensitivity was associated with greater NA and greater NA was associated with greater alcohol use. These findings were replicated with alcohol problems. An association also emerged between BAS sensitivity and marijuana use, mediated by PA (95%CIs [-0.296; -0.027]); greater BAS sensitivity was associated with greater PA and greater PA was associated with lower marijuana use. Finally, BIS sensitivity was associated with tobacco use through NA (95%CIs [0.023; 0.325]) and PA (95%CIs [0.004; 0.116]), with NA linked to greater, but PA linked to lower tobacco use. BAS sensitivity was also associated with tobacco use through PA (95%CIs [-0.395; -0.049]), with PA linked again to lower tobacco use.

CONCLUSIONS

There are unique and shared effects of domains of reinforcement sensitivity on adolescent substance use and these vary with index of dispositional affectivity and type of substance considered.

Effects of ethanol on plasma ghrelin levels in the rat during early and late adolescence

Ghrelin is an appetite-regulating peptide that is primarily secreted by endocrine cells in the stomach and is implicated in regulation of alcohol consumption and alcohol-reinforced behaviors. In the present study, adolescent Sprague-Dawley rats received intermittent ethanol (AIE) exposure by intragastric intubation (5 g/kg) or vapor inhalation, manipulations conducted between postnatal days (PD) 28-43. On the first and last day of AIE exposure, the level of intoxication was examined 1 h after ethanol gavage or upon removal from the vapor chamber. This was immediately followed by a blood draw for determination of the blood ethanol concentration (BEC) and plasma levels of acylated ghrelin (acyl-ghrelin; active). On PD29, plasma levels of acyl-ghrelin were significantly elevated in male (but not female) rats in response to acute ethanol exposure by both gastric gavage and vapor inhalation. Importantly, assessment of plasma acyl-ghrelin in response to repeated ethanol exposure revealed a complex interaction of both sex and method of AIE exposure. On PD43, vapor inhalation increased plasma acyl-ghrelin in both males and females compared to their air-control counterparts, whereas there was no change in plasma levels of acyl-ghrelin in either male or female rats in response to exposure by intragastric gavage. Assessment of plasma acyl-ghrelin following a 30-day ethanol-free period revealed AIE exposure did not produce a change in basal levels. In addition, an acute ethanol challenge in adult rats of 5 g/kg via gastric gavage had no effect on plasma ghrelin levels when assessed 1 h after initiation of exposure. Collectively, these observations suggest that acyl-ghrelin, a primary gut-brain signaling hormone, is elevated by ethanol during early adolescence independent of administration route, and in gender-dependent fashion.

Emotional memory impairment produced by binge drinking in mice is counteracted by the anti-inflammatory indomethacin

The Binge Drinking (BD) pattern of alcohol consumption, prevalent in adolescents and young adults, has been associated with memory impairment. In addition, evidence shows that alcohol abuse causes neuroinflammation, which may contribute to the brain damage produced by alcohol and explain its cognitive consequences. In this study, we evaluated the effectiveness of the anti-inflammatory indomethacin in counteracting the memory impairment produced by alcohol (ethanol) in adolescent mice of both sexes. Animals were randomly assigned to one of four groups for each sex: SS (saline + saline), SA (saline + alcohol), SI (saline + indomethacin) and AI (alcohol + indomethacin). They were injected acutely (Experiment 1) or chronically intermittent (Experiment 2) with saline, ethanol (3 g/kg) and indomethacin (10 mg/kg). All subjects were evaluated in an inhibitory avoidance task 96 h after treatment. With acute administration, SA groups showed significantly lower Test latencies than SS groups, while AI groups had similar latencies to controls. The chronic-intermittent administration of alcohol, an animal model of BD, produced significant emotional memory impairment -blocking learning in males- which was counteracted by indomethacin, as the AI groups had similar latencies to the SS groups. No significant differences were observed in locomotor activity or analgesia. In conclusion, alcohol BD (one or several episodes) impairs emotional memory in mice. This impairment is not secondary to the effects of alcohol BD on locomotor activity or pain sensitivity, and it is counteracted by indomethacin. Therefore, the memory impairment produced by alcohol BD seems to be mediated, in part, by neuroinflammatory processes. These findings open a window for new treatments for alcohol use disorders.

Association Between Socioeconomic Status and Early Initiation of Smoking, Alcohol Drinking, and Sexual Behavior Among Korean Adolescents

We analyzed data from the Korean Youth Risk Behavior Web-based Survey (N = 68 043), a nationally representative survey, to examine the association between early initiation of smoking, alcohol drinking, and sexual activity and socioeconomic determinants among adolescents. The prevalence rates of early initiation of smoking (i.e, starting at age 12 years or younger), alcohol drinking, and sexual activity were 4.8%, 10.3%, and 1.4%, respectively. Adolescents with a low level of perceived household income, low level of father's education, and those living without family were more likely to start these risky behaviors early. Early initiation of smoking was significantly affected by affordability.

Deficient Functioning of Frontostriatal Circuits During the Resolution of Cognitive Conflict in Cannabis-Using Youth

OBJECTIVE

Disturbances in self-regulatory control are involved in the initiation and maintenance of addiction, including cannabis use disorder. In adults, long-term cannabis use is associated with disturbances in frontostriatal circuits during tasks that require the engagement of self-regulatory control, including the resolution of cognitive conflict. Understudied are the behavioral and neural correlates of these processes earlier in the course of cannabis use disentangled from effects of long-term use. The present study investigated the functioning of frontostriatal circuits during the resolution of cognitive conflict in cannabis-using youth.

METHOD

Functional magnetic resonance imaging data were acquired from 28 cannabis-using youth and 32 age-matched healthy participants during the performance of a Simon task. General linear modeling was used to compare patterns of brain activation during correct responses to conflict stimuli across groups. Psychophysiologic interaction analyses were used to examine conflict-related frontostriatal connectivity across groups. Associations of frontostriatal activation and connectivity with cannabis use measures were explored.

RESULTS

Decreased conflict-related activity was detected in cannabis-using versus healthy control youth in frontostriatal regions, including the ventromedial prefrontal cortex, striatum, pallidum, and thalamus. Frontostriatal connectivity did not differ across groups, but negative connectivity between the ventromedial prefrontal cortex and striatum was detected in the 2 groups.

CONCLUSION

These findings are consistent with previous reports of cannabis-associated disturbances in frontostriatal circuits in adults and point to the specific influence of cannabis on neurodevelopmental changes in youth. Future studies should examine whether frontostriatal functioning is a reliable marker of cannabis use disorder severity and a potential target for circuit-based interventions.

Underage drinking as a natural part of growing up: a UK study of parental beliefs

Purpose

Parental beliefs about underage drinking are known to influence the drinking behaviours of their children. The purpose of this paper is to explore parental beliefs about their own child drinking alcohol and young people in general, in order to ascertain whether there is a need to target such beliefs in the design of public health interventions.

Design/methodology/approach

Parents of 11–18 year olds attending one of nine schools in the Midlands of England, UK were invited to take part. Participants completed a newly designed 40-item questionnaire measuring parental beliefs about the impact and causes of underage drinking; talking to their child about alcohol; and how much and how often they thought their child consumed alcohol.

Findings

In total, 185 parents took part in the study, reporting on their eldest child aged 18 or under. The majority of parents agreed that underage drinking is detrimental to child health and wellbeing. However, over 60 per cent believed that alcohol consumption is a “natural part of growing up”, and stronger agreement with this belief was associated with higher parental reports of alcohol consumption in their children.

Social implications

The majority of parents recognised the risks and negative effects of alcohol; however, many also believe it is a natural part of growing up. Parents may hold conflicting beliefs about underage drinking, which could impact on the drinking beliefs and behaviours of their children.

Originality/value

Public health interventions may need to counter the common parental belief that underage drinking is a normal part of growing up and therefore to be expected. Clear messages about the impact parent beliefs and behaviour have on young people drinking, to ensure parents recognise that messages are aimed at themselves, and not just “other parents” are imperative.

Population-neuroscience study of the Tokyo TEEN Cohort (pn-TTC): Cohort longitudinal study to explore the neurobiological substrates of adolescent psychological and behavioral development

AIM

Adolescence is a crucial stage of psychological development and is critically vulnerable to the onset of psychopathology. Our understanding of how the maturation of endocrine, epigenetics, and brain circuit may underlie psychological development in adolescence, however, has not been integrated. Here, we introduce our research project, the population-neuroscience study of the Tokyo TEEN Cohort (pn-TTC), a longitudinal study to explore the neurobiological substrates of development during adolescence.

METHODS

Participants in the first wave of the pn-TTC (pn-TTC-1) study were recruited from those of the TTC study, a large-scale epidemiological survey in which 3171 parent-adolescent pairs were recruited from the general population. Participants underwent psychological, cognitive, sociological, and physical assessment. Moreover, adolescents and their parents underwent magnetic resonance imaging (MRI; structural MRI, resting-state functional MRI, and magnetic resonance spectroscopy), and adolescents provided saliva samples for hormone analysis and for DNA analysis including epigenetics. Furthermore, the second wave (pn-TTC-2) followed similar methods as in the first wave.

RESULTS

A total of 301 parent-adolescent pairs participated in the pn-TTC-1 study. Moreover, 281 adolescents participated in the pn-TTC-2 study, 238 of whom were recruited from the pn-TTC-1 sample. The instruction for data request is available at: http://value.umin.jp/data-resource.html.

CONCLUSION

The pn-TTC project is a large-scale and population-neuroscience-based survey with a plan of longitudinal biennial follow up. Through this approach we seek to elucidate adolescent developmental mechanisms according to biopsychosocial models. This current biomarker research project, using minimally biased samples recruited from the general population, has the potential to expand the new research field of population neuroscience.

Associations of Early Age of First Intoxication with Past Year Drinking Contexts and Problems

BACKGROUND

Mechanisms underlying associations between early drinking and problems are largely unknown.

OBJECTIVES

We investigated (a) associations between early age of first intoxication (≤15 years) and past year drinking in different contexts and (b) whether early age of first intoxication is differentially associated with problems in these contexts.

METHODS

We used survey data collected in 2013-2014 from 405 past-year adolescent drinkers in 24 midsized California cities. Data included demographics; drinking behaviors; age of first intoxication; frequency of being at and drinking at restaurants, bars/nightclubs, outdoor places, and home; and problems. We used multilevel logistic and negative binomial models to account for the clustering of adolescents within cities. Probabilities were corrected to maintain family-wise error rates.

RESULTS

Early age of first intoxication was associated with a 120% increase in the odds of drinking at outdoor settings (OR = 2.20, p_c < .05). Early age of first intoxication was associated with increased numbers of problems related to drinking in restaurants (IRR = 5.72, p_c < .001), outdoor settings (IRR = 3.40, p_c < .001), and homes (IRR = 2.84, p_c < .001). Later intoxication (≥16 years) was not significantly associated with increased drinking or problems in any of these contexts.

CONCLUSIONS

Results suggest that underage drinkers who report early intoxication are more likely to drink at outdoor settings, but not other contexts. However, they may differentially experience drinking problems across contexts. To target youths who have experienced intoxication at an early age and to reduce problems, prevention interventions should focus on outdoor settings.

A systematic review: Candidate gene and environment interaction on alcohol use and misuse among adolescents and young adults

BACKGROUND AND OBJECTIVES

Youth drinking is a pervasive public health concern with serious negative developmental implications. Candidate gene and environment interaction studies (cGxE) show that environmental effects on drinking behaviors may differ by individuals' genotypes. Yet little is known about whether genetic and environmental effects on drinking behaviors are developmentally specific.

METHODS

This systematic review evaluated 42 cGxE studies of drinking in adolescence and young adulthood.

RESULTS

Although there are mixed findings, studies of cGxE effects involving DRD4, 5-HTTLPR, DRD2, and OPRM1 genotypes showed relatively consistent patterns. The effects of under-controlled environments (eg, low levels of parental monitoring) on early and middle adolescent drinking appeared to differ across DRD2 or OPRM1 genotypes. Effects of alcohol-facilitating environments (eg, heavy drinking peers) on late adolescent and young adult drinking appeared to differ across DRD4 or OPRM1 genotypes. Interactions between 5-HTTLPR genotype with stressful environments (eg, negative life events) were found throughout adolescence and young adulthood, although there were some inconsistencies regarding the risk-conferring allele. There was limited evidence for other cGxE effects due to the small number of studies.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This review suggests that GxE findings may advance our knowledge regarding which developmentally specific conditions result in the expression of candidate genes that influence youth alcohol use and misuse. However, since a significant number of studies had small sample sizes and most studies had small effect sizes, findings need replication across independent studies with large samples. (Am J Addict 2018;XX:1-19).

[Prediction of binge drinking in young adults: a cohort study over nine years]

Prediction of binge drinking in young adults: a cohort study over nine years Abstract.

OBJECTIVE

Which person characteristics and environmental factors predict binge drinking at age 21?

METHOD

A longitudinal observational study with a nine-year follow-up. A total of 5,176 adolescents from the German states Schleswig-Holstein and Saxony-Anhalt were surveyed in 2006 with paper-pencil questionnaires (mean age 12.6 years, SD = 0.6). A follow-up assessment was conducted in the year 2015. Baseline predictors were age, gender, school type, school performance, parenting style, early experience with alcohol, alcohol use of parents, alcohol use of friends, and sensation seeking. Primary outcome in 2015 was binge drinking at least once a month (six or more alcoholic drinks during one drinking occasion).

RESULTS

A subsample of 1,087 (20.9 %) of the former students could be surveyed nine years after baseline (mean age 21.6 years, SD = 0.8). One out of four (25.4 %) reported binge drinking at least once in a month. A multiple regression model revealed three significant predictors of binge drinking: male gender, early experience with alcohol and frequency of parental alcohol use at baseline.

CONCLUSIONS

Perceived frequency of parental alcohol use might be an important risk factor for children's alcohol use in early adulthood. Parents need to reflect their role as alcohol-specific socialization agents.

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.

Donepezil Reverses Dendritic Spine Morphology Adaptations and Fmr1 Epigenetic Modifications in Hippocampus of Adult Rats After Adolescent Alcohol Exposure

BACKGROUND

Adolescent intermittent ethanol (AIE) exposure produces persistent impairments in cholinergic and epigenetic signaling and alters markers of synapses in the hippocampal formation, effects that are thought to drive hippocampal dysfunction in adult rodents. Donepezil (Aricept), a cholinesterase inhibitor, is used clinically to ameliorate memory-related cognitive deficits. Given that donepezil also prevents morphological impairment in preclinical models of neuropsychiatric disorders, we investigated the ability of donepezil to reverse morphological and epigenetic adaptations in the hippocampus of adult rats exposed to AIE. Because of the known relationship between dendritic spine density and morphology with the fragile X mental retardation 1 (Fmr1) gene, we also assessed Fmr1 expression and its epigenetic regulation in hippocampus after AIE and donepezil pretreatment.

METHODS

Adolescent rats were administered intermittent ethanol for 16 days starting on postnatal day 30. Rats were treated with donepezil (2.5 mg/kg) once a day for 4 days starting 20 days after the completion of AIE exposure. Brains were dissected out after the fourth donepezil dose, and spine analysis was completed in dentate gyrus granule neurons. A separate cohort of rats, treated identically, was used for molecular studies.

RESULTS

AIE exposure significantly reduced dendritic spine density and altered morphological characteristics of subclasses of dendritic spines. AIE exposure also increased mRNA levels and H3-K27 acetylation occupancy of the Fmr1 gene in hippocampus. Treatment of AIE-exposed adult rats with donepezil reversed both the dendritic spine adaptations and epigenetic modifications and expression of Fmr1.

CONCLUSIONS

These findings indicate that AIE produces long-lasting decreases in dendritic spine density and changes in Fmr1 gene expression in the hippocampal formation, suggesting morphological and epigenetic mechanisms underlying previously reported behavioral deficits after AIE. The reversal of these effects by subchronic, post-AIE donepezil treatment indicates that these AIE effects can be reversed by up-regulating cholinergic function.

Adolescent Ethanol Exposure Enhances NMDA Receptor-Mediated Currents in Hippocampal Neurons: Reversal by Gabapentin

Adolescent intermittent ethanol (AIE) exposure compromises neural function into adulthood. We have reported that astrocyte-secreted thrombospondins, and their target neuronal receptors (α2δ−1) are upregulated in the hippocampus in adulthood after AIE, suggesting aberrant excitatory synaptogenesis and hyperexcitability in memory-related circuits. Gabapentin antagonizes the interaction of thrombospondins (TSPs) with the α2δ−1 receptor, and thus may reverse or ameliorate the effects of AIE on hippocampal function. Adolescent rats were exposed to AIE or vehicle. In adulthood, hippocampal slices were prepared. Half of the slices from each animal were pre-incubated in normal artificial cerebrospinal fluid (aCSF) while half were pre-incubated in aCSF containing gabapentin. Whole-cell voltage clamp recordings were then made from CA1 pyramidal cells in normal aCSF. Evoked, N-methyl-D-aspartate (NMDA) receptor-mediated currents were recorded at baseline, and after application of the GluN2B antagonist, RO25–6981. Current amplitudes were higher in neurons from AIE-exposed animals. However, no amplitude increase was observed in neurons from slices that had been pre-incubation in gabapentin. GluN2B antagonism reduced NMDA receptor-mediated currents more efficaciously in cells from AIE-exposed animals, an effect that was also reversed by pre-incubation in gabapentin. These findings identify a mechanism underlying the enduring effects of AIE, and a clinically-utilized agent that may ameliorate those effects.

Distinct cognitive performance and patterns of drug use among early and late onset cocaine users

INTRODUCTION

Adolescence is a crucial period for neurodevelopment, but few studies have investigated the impact of early cocaine use on cognitive performance and patterns of substance use.

METHODS

We evaluated 103 cocaine dependent inpatients divided in two groups: early-onset users (EOG; n=52), late-onset users (LOG; n=51), and 63 healthy controls. Neuropsychological functioning was evaluated using Digits Forward (DF) and Backward (DB), Trail Making Test (TMT), Stroop Color Word Test (SCWT), Controlled Oral Word Association Test (COWAT), Wisconsin Card Sorting Test (WCST), Rey Osterrieth Complex Figure Test (ROCFT), Frontal Assessment Battery (FAB), and Iowa Gambling Test (IGT). Use of alcohol and other drugs was assessed with the Addiction Severity Index (ASI-6).

RESULTS

Analyses of covariance controlling for age, IQ and years of education showed that EOG presented worse performance in attention span (DF, p=0.020), working memory (DB, p=0.001), sustained attention (WCST, p=0.030), declarative memory (ROCFT, p=0.031) and general executive functioning (FAB, p=0.003) when compared with the control group. LOG presented impairments on divided attention (TMT, p=0.003) and general executive functioning (FAB, p=0.001) in relation to the control group. EOG presented higher use of cannabis and alcohol than LOG (p≤0.001).

CONCLUSION

Early-onset cocaine users display more pronounced neuropsychological alterations than controls, as well as a greater frequency of polydrug consumption than LOG. The prominent cognitive deficits in EOG probably reflect the deleterious interference of cocaine use with early stages of neurodevelopment. This may be related to more severe clinical characteristics of substance disorder in this subgroup, including polysubstance abuse.

Ethanol Interactions With Dexmethylphenidate and dl-Methylphenidate Spheroidal Oral Drug Absorption Systems in Healthy Volunteers

BACKGROUND/PURPOSE

Ethanol coadministered with immediate-release dl-methylphenidate (dl-MPH) or dexmethylphenidate (d-MPH) significantly increases the geomean maximum plasma concentration (Cmax) of d-MPH 22% and 15%, respectively, and elevates overall drug exposure and psychostimulant effects. We asked the question: Are these ethanol-MPH interactions based more fundamentally on (1) inhibition of postabsorption d-MPH metabolism or (2) acceleration of MPH formulation gastric dissolution by ethanol in the stomach? This was investigated using the pulsatile, distinctly biphasic, spheroidal oral drug absorption systems of dl-MPH and d-MPH.

METHODS

In a randomized, 4-way crossover study, 14 healthy subjects received pulsatile dl-MPH (40 mg) or d-MPH (20 mg), with or without ethanol (0.6 g/kg), dosed 4 hours later. These 4 hours allowed the delayed-release second MPH pulse to reach a more distal region of the gut to preclude gastric biopharmaceutical influences. Plasma was analyzed using a highly sensitive chiral method. Subjective/physiological effects were recorded.

FINDINGS/RESULTS

Ethanol increased the second pulse of d-MPH Cmax for dl-MPH by 35% (P < 0.01) and the partial area under the plasma concentration curve from 4 to 8 hours by 25% (P < 0.05). The respective values for enantiopure d-MPH were 27% (P = 0.001) and 20% (P < 0.01). The carboxylesterase 1-mediated transesterification metabolite ethylphenidate served as a biomarker for coexposure. Ethanol significantly potentiated stimulant responses to either formulation.

IMPLICATIONS/CONCLUSIONS

These findings support drug dispositional interactions between ethanol and MPH as dominant over potential biopharmaceutical considerations. Understanding the pharmacology underlying the frequent coabuse of MPH-ethanol provides rational guidance in the selection of first-line pharmacotherapy for comorbid attention-deficit/hyperactivity disorder-alcohol use disorder.

Differences between adolescents and adults in the acute effects of PCP and ketamine and in sensitization following intermittent administration

Adolescence is a phase of development during which many physiological and behavioral changes occur, including increased novelty seeking and risk taking. In humans, this is reflected in experimentation with drugs. Research demonstrates that drug use that begins during adolescence is more likely to lead to addiction than drug use that begins later in life. Despite this, relatively little is known of the effects of drugs in adolescence, and differences in response between adolescents and adults. PCP and ketamine are popular club drugs, both possessing rewarding properties that could lead to escalating use. Drug sensitization (or reverse tolerance), which refers to an increase in an effect of a drug following repeated use, has been linked with the development of drug cravings that is a hallmark of addiction. The current work investigated the acute response and the development of sensitization to PCP and ketamine in adolescent and adult rats. Periadolescent Sprague-Dawley rats (30days or 38days of age), and young adults (60days of age) received PCP (6mg/kg IP) or ketamine (20mg/kg IP) once every three days, for a total of five drug injections. Adolescents and adults showed a stimulant response to the first injection of either drug, however the response was considerably greater in the youngest adolescents and lowest in the adults. With repeated administration, adults showed a robust escalation in activity that was indicative of the development of sensitization. Adolescents showed a flatter trajectory, with similar high levels of activity following an acute treatment and after five drug treatments. The results demonstrate important distinctions between adolescents and adults in the acute and repeated effects of PCP and ketamine.

Binge Drinking in Young University Students Is Associated with Alterations in Executive Functions Related to Their Starting Age

Our aim was to evaluate whether or not alcohol consumption in the form of binge drinking is associated with alterations of memory and executive functions in a population of university students. At the same time, we have studied the role of potential modulating factors, such as the APOE genotype or physical exercise.University students enrolled in academic year 2013–2014 at Escuelas Universitarias Gimbernat-Cantabria, affiliated with the University of Cantabria, were invited to participate in the study. We gathered sociodemographic data and details regarding the lifestyle of 206 students (mean age 19.55 ± 2.39; 67.5% women). We evaluated memory and executive functions via a series of validated cognitive tests. Participants were classified as binge drinkers (BD) and non-BD. Using Student's t-distribution we studied the association between cognitive tests and BD patterns. Multivariate analyses were carried out via multiple linear regression. 47.6% of the students were found to be BD. The BD differed significantly from the non-BD in their results in the executive functions test TMT B (43.41 ± 13.30 vs 37.40 ± 9.77; p = 0.0003). Adjusting by age, sex, academic records, age at which they started consuming alcohol, cannabis consumption, level of physical activity and other possible modifying variables, the association was statistically significant (p = 0.009). We noticed a statistically significant inverse correlation (Pearson’s r² = -0.192; p = 0.007) between TMT B and starting age of alcohol consumption. Differences were observed in another executive functions test, TMT A, but only in the group of women (19.73±6.1 BD vs 17.78±5.4 non-BD p = 0.05). In spite of the young age of our participants, BD was associated with a lower performance in the executive functions test (TMT B). These deficits were related to the age at which they started drinking alcohol, suggesting an accumulative effect.

Increased vulnerability to ethanol consumption in adolescent maternal separated mice

The purpose of this study was to evaluate the effects of early life stress on the vulnerability to ethanol consumption in adolescence. To this aim, mice were separated from their mothers for 12 hours/day on postnatal days 8 and 12. Emotional behavior (light-dark box, elevated plus maze and tail suspension tests) and pre-attentional deficit (pre-pulse inhibition) were evaluated in adolescent maternal separated (MS) mice. Alterations of the corticotropin-releasing factor (CRF), glucocorticoid receptor (NR3C1), tyrosine hydroxylase (TH), mu-opioid receptor (MOr), brain-derived neurotrophic factor (BDNF), neuronal nuclei (NeuN), microtubule-associated protein 2 (MAP2) and neurofilament heavy (NF200)-immunoreactive fibers were studied in the paraventricular nucleus of the hypothalamus (PVN), ventral tegmental area (VTA), nucleus accumbens (NAc) or hippocampus (HIP). The effects of maternal separation (alone or in combination with additional stressful stimuli) on ethanol consumption during adolescence were evaluated using the oral ethanol self-administration paradigm. MS mice presented mood-related alterations and pre-attentional deficit. Increased CRF, MOr and TH, and reduced BDNF, NR3C1, NeuN, MAP2 and NF200-immunoreactive fibers were observed in the PVN, NAc and HIP of adolescent MS mice. In the oral ethanol self-administration test, adolescent MS mice presented higher ethanol consumption and motivation. Exposure to additional new stressful stimuli during adolescence significantly increased the vulnerability to ethanol consumption induced by maternal separation. These results clearly demonstrated that exposure to early life stress increased the vulnerability to ethanol consumption, potentiated the effects of stressful stimuli exposure during adolescence on ethanol consumption and modified the expression of key targets involved in the response to stress, ethanol reinforcing properties and cognitive processes.

Short- and long-term psychosocial of a single episode of alcoholic intoxication: a cohort study among Dutch adolescents

The short- and long-term psychological consequences of a single episode of alcohol intoxication in adolescents are unknown. Twenty-four adolescents (12 M, 12 F), mean age 18.3 ± 1.1 years, who had been admitted to the pediatric ward with alcohol intoxication (mean age at admission 15.6 ± 1.1) and thirty-two parents were interviewed on the intoxication episode and the subsequent consequences. This interview took place 2-3 years after the alcohol intoxication. At the same time, all participants completed questionnaires, assessing general and demographic information, detailed information about current alcohol use, present-day health-related quality of life, and psychological well-being. We observed that short-term (<6 months) psychosocial consequences on family life, family rules, friendships, and school were retrospectively judged more neutral and even more positive than negative by adolescents and their parents. Eighty-six percent of all reported changes by adolescents and parents, directly after the intoxication, lasted 6 months or less. At follow-up present-day quality of life was comparable to the norm, social functioning was significantly better and their mental health proved to be within the normal range (no emotional and behavioral problems). Since the intoxication, none of the participants had dropped out of school and their present-day alcohol use was comparable to estimated averages for their age.

CONCLUSION

Short- and long-term psychosocial consequences of a single episode of alcohol intoxication were positively judged by adolescents and their parents.

WHAT IS KNOWN

• Alcohol abuse among adolescents is a growing concern both in society and pediatrics. What is new: • This manuscript describes short and long term psychological consequences of a single episode of alcohol intoxication in adolescents.

The interaction between anxiety sensitivity and cigarette smoking level in relation to sleep onset latency among adolescent cigarette smokers

Cigarette smoking during adolescence is linked to a number of sleep disturbances and has been consistently linked to sleep onset latency among adults. However, little research has examined factors that may influence the relation between cigarette smoking level and sleep onset latency among adolescents. One factor that may be particularly important in this regard is anxiety sensitivity (AS). The current study examined whether cigarette smoking level interacted with AS in its association with sleep onset latency among 94 adolescent (Mage = 15.72) cigarette smokers. As hypothesized, AS interacted with smoking level to relate to sleep onset latency, even after controlling for age and gender. This relation was specific to sleep onset latency as opposed to other types of sleep disturbances, and that adolescents who smoked at higher levels tended to go to sleep later and wake up later than adolescents who smoked at relatively lower levels.

Contextual influences on early drinking: Characteristics of drinking and nondrinking days

Research characterizing the adolescent drinking context is limited, often relies on samples of current drinkers reporting on recent/last or typical drinking experiences, and provides little information about the context of very early use. The present study uses repeated monthly assessments to describe the context of drinking days and matched nondrinking days to determine the unique risk associated with different drinking-related characteristics. Additionally, we used latent class analysis to empirically identify key configurations of drinking-related characteristics and both family- and nonfamily-related environmental characteristics (social context, physical location, source of alcohol). Data included 688 days (344 drinking days, 344 nondrinking days) from 164 middle-school students enrolled in a prospective study on drinking initiation and progression (62% female; 26% non-White, 11% Hispanic). Results supported 4 patterns: (a) heavier drinking occurring in a peer context, lighter drinking occurring in (b) a family context or (c) a peer context, and (d) drinking alcohol obtained at home without permission. Latent classes varied as a function of gender, age, peer norms, and parenting behaviors as well as alcohol type and perceived alcohol availability. Findings indicated that highly endorsed contexts were not necessarily the riskiest ones, and simply targeting an oft-reported source of alcohol, physical location, or social context may not be an effective strategy for reducing underage drinking. Additionally, although greater monitoring and anticipated parent reaction to drinking are typically protective against adolescent drinking, we found they were associated with parent-sanctioned drinking, suggesting the role of parenting practices must be considered in the context of drinking pattern. (PsycINFO Database Record

The roles of sex, anxious reactivity to bodily arousal, and anxiety sensitivity in coping motives for cigarette smoking among adolescents

Evidence suggests that smoking to cope among adolescents is associated with a number of problematic outcomes (e.g., greater smoking frequency, higher rates of dependence). It is thus imperative to better understand factors that may increase the likelihood of smoking to cope among adolescents. Research suggests anxiety sensitivity (AS) is associated with smoking to cope among adults, although the link between AS and coping motives for cigarette use among youth is less clear. Gender differences have also been noted in AS. The current study investigates this association using a biological challenge paradigm. Specifically, the indirect effects of anxious reactivity to bodily arousal on the relation between the physical and mental AS factors and coping motives for cigarette smoking were examined within a sample of 108 adolescent cigarette smokers. Gender was examined as a moderator. Results suggested significant indirect effects of self-reported anxiety in response to bodily arousal on the relation between physical AS and coping motives for cigarette smoking. This indirect effect was moderated by gender, such that it was significant for females but not males. Models examining AS mental concerns and psychophysiological responding to the challenge were not significant. These results suggest that, relative to their low AS counterparts, female adolescents high in physical concerns respond with elevated anxiety in response to interoceptive arousal and, in turn, endorse elevated coping-related smoking motives. Findings are discussed in terms of implications for understanding the nature and origins of coping-related smoking motives and how such information can be used to inform intervention efforts. (PsycINFO Database Record

A neuroscience perspective on sexual risk behavior in adolescence and emerging adulthood

Late adolescence and emerging adulthood (specifically ages 15-24) represent a period of heightened sexual risk taking resulting in the greatest annual rates of sexually transmitted infections and unplanned pregnancies in the US population. Ongoing efforts to prevent such negative consequences are likely to benefit from a deepening of our understanding of biological mechanisms through which sexual risk taking emerges and biases decision making during this critical window. Here we present a neuroscience framework from which a mechanistic examination of sexual risk taking can be advanced. Specifically, we adapt the neurodevelopmental triadic model, which outlines how motivated behavior is governed by three systems: approach, avoidance, and regulation, to sexual decision making and subsequent risk behavior. We further propose a testable hypothesis of the triadic model, wherein relatively decreased threat-related amygdala reactivity and increased reward-related ventral striatum reactivity leads to sexual risk taking, which is particularly exaggerated during adolescence and young adulthood when there is an overexpression of dopaminergic neurons coupled with immature top-down prefrontal cortex regulation. We conclude by discussing how future research based on our adapted triadic model can inform ongoing efforts to improve intervention and prevention efforts.

The prospective association between sipping alcohol by the sixth grade and later substance use

OBJECTIVE

Although there is a clear association between early use of alcohol and short- and long-term adverse outcomes, it is unclear whether consumption of minor amounts of alcohol (less than a full drink) at a young age is prognostic of risk behaviors in later adolescence.

METHOD

Data were taken from 561 students enrolled in an ongoing prospective web-based study on alcohol initiation and progression (55% female; 25% White non-Hispanic). Based on a combination of monthly and semiannual surveys, we coded whether participants sipped alcohol before sixth grade and examined associations between early sipping and alcohol consumption by fall of ninth grade, as well as other indices of problem behavior. Participants also reported on the context of the first sipping event.

RESULTS

The prevalence of sipping alcohol by fall of sixth grade was 29.5%. Most participants indicated that their first sip took place at their own home, and the primary source of alcohol was an adult, usually a parent. Youth who sipped alcohol by sixth grade had significantly greater odds of consuming a full drink, getting drunk, and drinking heavily by ninth grade than nonsippers. These associations held even when we controlled for temperamental, behavioral, and environmental factors that contribute to proneness for problem behavior, which suggests that sipping is not simply a marker of underlying risk.

CONCLUSIONS

Our findings that early sipping is associated with elevated odds of risky behaviors at high school entry dispute the idea of sipping as a protective factor. Offering even just a sip of alcohol may undermine messages about the unacceptability of alcohol consumption for youth.

Early unpredictability predicts increased adolescent externalizing behaviors and substance use: A life history perspective

According to evolutionary life history models, environmental harshness and unpredictability can both promote a fast life history strategy characterized by increased risk taking and enacting short-term, opportunistic behaviors. The current longitudinal study tests whether environmental unpredictability during childhood has stronger effects on risky behavior during adolescence than harshness, and whether there may be an early "sensitive period" during which unpredictability has particularly strong and unique effects on these outcomes. Using data from the Minnesota Longitudinal Study of Risk and Adaptation, prospective assessments of environmental unpredictability (changes in residence, cohabitation, and parental occupation) and harshness (mean socioeconomic status) from birth into adolescence were used to predict self-reported externalizing behaviors and substance use at age 16 (N = 220). Exposure to greater early unpredictability (between ages 0 and 5) predicted more externalizing behaviors as well as more alcohol and marijuana use at age 16, controlling for harshness and later unpredictability (between ages 6 and 16). Harshness predicted adolescent substance use, and later unpredictability predicted adolescent externalizing behaviors at the trend level. Early unpredictability and harshness also interacted, such that the highest levels of risk taking occurred in individuals who experienced more early unpredictability and lived in harsher environments. Age 16 externalizing behaviors, but not substance use, mediated the association between early unpredictability and externalizing/criminal behaviors at age 23. We discuss how exposure to early environmental unpredictability may alter biological and social-cognitive functioning from a life history perspective.

Adolescent Alcohol Exposure Amplifies the Incentive Value of Reward-Predictive Cues Through Potentiation of Phasic Dopamine Signaling

Adolescent alcohol use remains a major public health concern due in part to well-established findings implicating the age of onset in alcohol use in the development of alcohol use disorders and persistent decision-making deficits in adults. We have previously demonstrated that moderate adolescent alcohol consumption in rats promotes suboptimal decision making and an associated perturbation in mesolimbic dopamine transmission in adulthood. Dopamine-dependent incentive learning processes are an integral component of value-based decision making and a fundamental element to many theoretical accounts of addiction. Thus we tested the hypothesis that adolescent alcohol use selectively alters incentive learning processes through perturbation of mesolimbic dopamine systems. To assess incentive learning, behavioral and neurochemical measurements were made during the acquisition, maintenance, extinction, and reacquisition of a Pavlovian conditioned approach procedure in adult rats with a history of adolescent alcohol consumption. We show that moderate adolescent alcohol consumption potentiates stimulus-evoked phasic dopamine transmission, measured in vivo by fast-scan cyclic voltammetry, in adulthood and biases individuals toward a dopamine-dependent incentive learning strategy. Moreover, we demonstrate that animals exposed to alcohol in adolescence are more sensitive to an unexpected variation in reward outcomes. This pattern of phasic dopamine signaling and the associated bias in learning may provide a mechanism for the well-documented vulnerability of individuals with early-life alcohol use for alcohol use disorders in adulthood.

Binge drinking and cognitive impairment in young people

AIMS AND OBJECTIVES

To investigate the links between the binge pattern of drinking and the development of cognitive impairment in young adults in the UK. To determine from the findings whether cognitive impairment is an additional public health concern manifesting from this form of alcohol misuse and its relevance to nursing practice.

BACKGROUND

Young adults in the UK are participating in binge drinking; a 'harmful' form of alcohol misuse. Morbidity and mortality associated with alcohol misuse is already a public health concern.

DESIGN

Literature review.

METHOD

Multiple database searches were undertaken, which revealed three case-control studies. The studies all investigated the binge pattern of drinking as well as meeting the following inclusion criteria; primary research published from 2005 onwards, used a human sample, participants were aged 18 to 24 and cognitive function was tested.

RESULTS

The quantitative data found cognitive impairment present in young adult binge drinkers, specifically in regions of the frontal lobe, temporal lobe and hippocampus. Individually the studies did not pose strong enough evidence to generalise findings. However, collectively the core findings along with previous studies can validate the link between binge drinking and cognitive impairment.

CONCLUSION

Nurse-led alcohol misuse screening and brief intervention is the most effective public health prevention strategy. It is important for nurses to keep abreast of current evidence to better inform their practice and the information they provide to their service users. This review emphasises the need for nurses to routinely screen young adults and address the associated risk to cognitive function when participating in harmful drinking.

Adolescent alcohol exposure alters GABAA receptor subunit expression in adult hippocampus

BACKGROUND

The long-term consequences of adolescent alcohol abuse that persist into adulthood are poorly understood and have not been widely investigated. We have shown that intermittent exposure to alcohol during adolescence decreased the amplitude of GABAA receptor (GABAA R)-mediated tonic currents in hippocampal dentate granule cells in adulthood. The aim of this study was to investigate the enduring effects of chronic intermittent alcohol exposure during adolescence or adulthood on the expression of hippocampal GABAA Rs.

METHODS

We used a previously characterized tissue fractionation method to isolate detergent resistant membranes and soluble fractions, followed by Western blots to measure GABAA R protein expression. We also measured mRNA levels of GABAA R subunits using quantitative real-time polymerase chain reaction.

RESULTS

Although the protein levels of α1-, α4-, and δ-GABAA R subunits remained stable between postnatal day (PD) 30 (early adolescence) and PD71 (adulthood), the α5-GABAA R subunit was reduced across that period. In rats that were subjected to adolescent intermittent ethanol (AIE) exposure between PD30 and PD46, there was a significant reduction in the protein levels of the δ-GABAA R, in the absence of any changes in mRNA levels, at 48 hours and 26 days after the last ethanol (EtOH) exposure. Protein levels of the α4-GABAA R subunit were significantly reduced, but mRNA levels were increased, 26 days (but not 48 hours) after the last AIE exposure. Protein levels of α5-GABAA R were not changed by AIE, but mRNA levels were reduced at 48 hours but normalized 26 days after AIE. In contrast to the effects of AIE, chronic intermittent ethanol (CIE) exposure during adulthood had no effect on expression of any of the GABAA R subunits examined.

CONCLUSIONS

AIE produced both short- and long-term alterations of GABAA R subunits mRNA and protein expression in the hippocampus, whereas CIE produced no long-lasting effects on those measures. The observed reduction of protein levels of the δ-GABAA R, specifically, is consistent with previously reported altered hippocampal GABAA R-mediated electrophysiological responses after AIE. The absence of effects of CIE underscores the emerging view of adolescence as a time of distinctive vulnerability to the enduring effects of repeated EtOH exposure.

How do we 'learn' addiction? Risk factors and mechanisms getting addicted to alcohol

BACKGROUND

Alcohol dependence is one of the leading contributors to the burden of disease in the world. A range of genetic and environmental risk factors has been identified to date, and preclinical and clinical studies including imaging studies have identified neuronal networks involved in the development of alcohol dependence.

METHODS

We review genetic and environmental risk factors for the development of alcohol addiction as well as structural and neuronal changes, including their transmitter systems, due to regular alcohol intake.

RESULTS

Stress as well as family background and, in juveniles, the peer group could be identified as environmental risk factors for alcohol dependence. Heritability is estimated at around 50%, and it seems to be comparable in women and men. There is ongoing research on a broad range of putative endophenotypes such as tolerance of the effects of alcohol intake or personal traits like 'impulsivity'. On the neurobiological level, chronic alcohol intake seems to render mesolimbic circuits hypersensitive to alcohol and alter the motivational reward system including dopaminergic neurotransmission.

CONCLUSION

Environmental and genetic risk factors, and especially their interaction, facilitate the development of alcohol dependence. Ongoing alcohol intake results in profound alterations of neuronal systems crucial for motivation, learning, memory and cognition control. Future studies should further combine the knowledge of neurobiological mechanisms and risk factors to develop new prevention strategies.

Alcohol use across the lifespan: An analysis of adolescent and aged rodents and humans

Adolescence and old age are unique periods of the lifespan characterized by differential sensitivity to the effects of alcohol. Adolescents and the elderly appear to be more vulnerable to many of alcohol's physiological and behavioral effects compared to adults. The current review explores the differential effects of acute alcohol, predominantly in terms of motor function and cognition, in adolescent and aged humans and rodents. Adolescents are less sensitive to the sedative-hypnotic, anxiolytic, and motor-impairing effects of acute alcohol, but research results are less consistent as it relates to alcohol's effects on cognition. Specifically, previous research has shown adolescents to be more, less, and similarly sensitive to alcohol-induced cognitive deficits compared to adults. These equivocal findings suggest that learning acquisition may be differentially affected by ethanol compared to memory, or that ethanol-induced cognitive deficits are task-dependent. Older rodents appear to be particularly vulnerable to the motor- and cognitive-impairing effects of acute alcohol relative to younger adults. Given that alcohol consumption and abuse is prevalent throughout the lifespan, it is important to recognize age-related differences in response to acute and long-term alcohol. Unfortunately, diagnostic measures and treatment options for alcohol dependence are rarely dedicated to adolescent and aging populations. As discussed, although much scientific advancement has been made regarding the differential effects of alcohol between adolescents and adults, research with the aged is underrepresented. Future researchers should be aware that adolescents and the aged are uniquely affected by alcohol and should continue to investigate alcohol's effects at different stages of maturation.

A field investigation of the effects of drinking consequences on young adults' readiness to change

In the research on readiness to change (RTC) one's drinking, there has been little assessment of the influence of positive drinking consequences or other potential moderating variables. To address these limitations, we examined how young adults' RTC their alcohol consumption shortly following a drinking episode was associated with self-reported drinking consequences, as well as any potential moderating effects of gender and Breath Alcohol Concentration (BrAC). In street interviews outside bars, 238 young adults were administered questionnaires about their drinking, including a measure examining participants' current readiness to reduce their alcohol consumption. Within 72h of their drinking episode, 67 participants (36 males; entire sample Mage=20.90years, Range=18-26years) completed an online survey, once again measuring RTC as well as positive and negative drinking consequences. Consistent with our hypothesis, positive drinking consequences were negatively associated with participants' changes in RTC. Additionally, a three-way interaction of gender×BrAC×positive drinking consequences on RTC showed that females with low BrACs reported higher RTC scores when they had endorsed fewer positive drinking consequences. Interestingly, negative drinking consequences alone did not impact individuals' RTC. Because positive drinking consequences were a significantly better predictor of RTC than were negative drinking consequences, researchers are advised to examine both types of consequences in future studies. Finally, effective alcohol education programs for those who have never consumed alcohol as well as social drinkers should include consideration of the experience of positive outcomes.

Reinforcing properties and neurochemical response of ethanol within the posterior ventral tegmental area are enhanced in adulthood by periadolescent ethanol consumption

Alcohol drinking during adolescence is associated with increased alcohol drinking and alcohol dependence in adulthood. Research examining the biologic consequences of adolescent ethanol (EtOH) consumption on the response to EtOH in the neurocircuitry shown to regulate drug reinforcement is limited. The experiments were designed to determine the effects of periadolescent alcohol drinking on the reinforcing properties of EtOH within the posterior ventral tegmental area (pVTA) and the ability of EtOH microinjected into the pVTA to stimulate dopamine (DA) release in the nucleus accumbens shell (AcbSh). EtOH access (24-hour free-choice) by alcohol-preferring rats occurred during postnatal days (PND) 30-60. Animals were tested for their response to EtOH after PND 85. Intracranial self-administration techniques were performed to assess EtOH self-infusion into the pVTA. In the second experiment, rats received microinjections of EtOH into the pVTA, and dialysis samples were collected from the AcbSh. The results indicate that in rats that consumed EtOH during adolescence, the pVTA was more sensitive to the reinforcing effects of EtOH (a lower concentration of EtOH supported self-administration) and the ability of EtOH microinjected into the pVTA to stimulate DA release in the AcbSh was enhanced (sensitivity and magnitude). The data indicate that EtOH consumption during adolescence altered the mesolimbic DA system to be more sensitive and responsive to EtOH. This increase in the response to EtOH within the mesolimbic DA during adulthood could be part of biologic sequelae that are the basis for the deleterious effects of adolescent alcohol consumption on the rate of alcoholism during adulthood.

The declining trend in Swedish youth drinking: collectivity or polarization?

AIMS

Alcohol consumption among youth in Sweden has declined markedly during the last decade. This study aims to tackle the following research questions: (i) how is the decrease in drinking distributed across consumption categories; and (ii) is the pattern of change in consumption consistent with Skog's theory of the collectivity of drinking behaviour?

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

We analysed data from the nationally representative annual school survey of alcohol and drug habits among Swedish 9th-grade students (aged 15-16 years) covering the period 2000-12 (n ≈ 5000/year). Respondents were divided into seven drinking groups based on their relative ranking on consumption, which was measured by beverage-specific quantity and frequency items summarized into a measure of overall drinking in litres of 100% alcohol per year. In addition, the mean number of heavy episodic drinking occasions (HED) was computed for each drinking group.

FINDINGS

The decline in consumption among Swedish youth was mirrored in all seven drinking groups, although the relative decrease was smaller for heavy drinkers (top 5%) than for light drinkers (below the median). Among the top 5%, the average annual decrease was 2% (P = 0.027), while the corresponding figure for light drinkers was 28.9% (P < 0.001). The reverse pattern was true when looking at the absolute decrease. The decrease among the top 5% accounted for 26.1% of the decrease in mean consumption during the study period, whereas the light drinkers accounted for 2.9%. There was a marked relation between overall consumption, on one hand, and mean consumption and HED, on the other hand, in each of the seven drinking groups.

CONCLUSION

The marked decrease in youth drinking in Sweden that occurred during the period 2000-12 was manifest at all consumption levels. The findings are consistent with Skog's theory of the collectivity of drinking behaviour.

Effects of voluntary alcohol intake on risk preference and behavioral flexibility during rat adolescence

Alcohol use is common in adolescence, with a large portion of intake occurring during episodes of binging. This pattern of alcohol consumption coincides with a critical period for neurocognitive development and may impact decision-making and reward processing. Prior studies have demonstrated alterations in adult decision-making following adolescent usage, but it remains to be seen if these alterations exist in adolescence, or are latent until adulthood. Here, using a translational model of voluntary binge alcohol consumption in adolescents, we assess the impact of alcohol intake on risk preference and behavioral flexibility during adolescence. During adolescence (postnatal day 30-50), rats were given 1-hour access to either a 10% alcohol gelatin mixture (EtOH) or a calorie equivalent gelatin (Control) at the onset of the dark cycle. EtOH consuming rats were classified as either High or Low consumers based on intake levels. Adolescent rats underwent behavioral testing once a day, with one group performing a risk preference task, and a second group performing a reversal-learning task during the 20-day period of gelatin access. EtOH-High rats showed increases in risk preference compared to Control rats, but not EtOH-Low animals. However, adolescent rats did a poor job of matching their behavior to optimize outcomes, suggesting that adolescents may adopt a response bias. In addition, adolescent ethanol exposure did not affect the animals' ability to flexibly adapt behavior to changing reward contingencies during reversal learning. These data support the view that adolescent alcohol consumption can have short-term detrimental effects on risk-taking when examined during adolescence, which does not seem to be attributable to an inability to flexibly encode reward contingencies on behavioral responses.

Adolescent drinking and motivated decision-making: a cotwin-control investigation with monozygotic twins

The present study used a monozygotic (MZ) cotwin-control (CTC) design to investigate associations between alcohol use and performance on the Iowa gambling task (IGT) in a sample of 96 adolescents (half female). The MZ CTC design is well suited to shed light on whether poor decision-making, as reflected on IGT performance, predisposes individuals to abuse substances or is a consequence of use. Participants completed structural MRI scans as well, from which we derived gray matter volumes for cortical and subcortical regions involved in IGT performance and reduced in adolescents with problematic alcohol use. Drinking was associated with poorer task performance and with reduced volume of the left lateral orbital-frontal cortex. CTC analyses indicated that the former was due to differences between members of twin pairs in alcohol use (suggesting a causal effect of alcohol), whereas the latter was due to factors shared by twins (consistent with a pre-existing vulnerability for use). Although these preliminary findings warrant replication, they suggest that normative levels of alcohol use may diminish the quality of adolescent decision-making and thus have potentially important public health implications.

Adolescent alcohol exposure and persistence of adolescent-typical phenotypes into adulthood: a mini-review

Alcohol use is typically initiated during adolescence, which, along with young adulthood, is a vulnerable period for the onset of high-risk drinking and alcohol abuse. Given across-species commonalities in certain fundamental neurobehavioral characteristics of adolescence, studies in laboratory animals such as the rat have proved useful to assess persisting consequences of repeated alcohol exposure. Despite limited research to date, reports of long-lasting effects of adolescent ethanol exposure are emerging, along with certain common themes. One repeated finding is that adolescent exposure to ethanol sometimes results in the persistence of adolescent-typical phenotypes into adulthood. Instances of adolescent-like persistence have been seen in terms of baseline behavioral, cognitive, electrophysiological and neuroanatomical characteristics, along with the retention of adolescent-typical sensitivities to acute ethanol challenge. These effects are generally not observed after comparable ethanol exposure in adulthood. Persistence of adolescent-typical phenotypes is not always evident, and may be related to regionally specific ethanol influences on the interplay between CNS excitation and inhibition critical for the timing of neuroplasticity.

Worth the wait: effects of age of onset of marijuana use on white matter and impulsivity

RATIONALE

Marijuana (MJ) use continues to rise, and as the perceived risk of using MJ approaches an all-time historic low, initiation of MJ use is occurring at even younger ages. As adolescence is a critical period of neuromaturation, teens and emerging adults are at greater risk for experiencing the negative effects of MJ on the brain. In particular, MJ use has been shown to be associated with alterations in frontal white matter microstructure, which may be related to reports of increased levels of impulsivity in this population.

OBJECTIVES

The aim of this study was to examine the relationship between age of onset of MJ use, white matter microstructure, and reported impulsivity in chronic, heavy MJ smokers.

METHODS

Twenty-five MJ smokers and 18 healthy controls underwent diffusion tensor imaging and completed the Barratt Impulsiveness Scale. MJ smokers were also divided into early onset (regular use prior to age 16) and late onset (age 16 or later) groups in order to clarify the impact of age of onset of MJ use on these variables.

RESULTS

MJ smokers exhibited significantly reduced fractional anisotropy (FA) relative to controls, as well as higher levels of impulsivity. Earlier MJ onset was also associated with lower levels of FA. Interestingly, within the early onset group, higher impulsivity scores were correlated with lower FA, a relationship that was not observed in the late onset smokers.

CONCLUSIONS

MJ use is associated with white matter development and reported impulsivity, particularly in early onset smokers.

The gender-specific association between age at first drink and later alcohol drinking patterns in Korea

This study investigated the association between the age at first drink and later alcohol drinking patterns, and analyzed whether differences in the association exist among Korean adults according to gender. The subjects included 10,649 adults (5,405 men and 5,244 women) from the fourth Korean National Health and Nutrition Examination Survey between 2007 and 2009, which extracted the standard survey household by using the proportional systematic sampling method. Baseline individual characteristics, the age at first drink, and individual alcohol drinking patterns were obtained by specially trained interviewers or examiners. The association between the age at first drink and the adult alcohol drinking patterns was summarized with odds ratios and their confidence intervals obtained from multiple logistic regression analysis with sampling weights of KNHANES complex sample survey design. The results of this study show that age, co-habitation, occupation, smoking, and self-rated stress level were significantly related to the drinking patterns for men, whereas education, co-habitation, smoking, and self-rated stress level were significant factors for the drinking patterns of women. The association between the age at first drink and the adult alcohol consumption was significant for both genders and, interestingly, the alcohol drinking patterns were significantly differed by gender even after controlling for the individual characteristics. These results imply a need for gender-specific strategies to prevent hazardous alcohol consumption at a later time for Korean.

Wahrgenommene Verfügbarkeit und Alkoholkonsum Jugendlicher im Längsschnitt

Zielsetzung: Untersuchung des Einflusses der wahrgenommenen Verfügbarkeit von Alkohol auf die Initiierung des Rauschtrinkens im Kindes- und Jugendalter Methodik: Es handelt sich um eine längsschnittliche Beobachtungsstudie mit drei Erhebungszeitpunkten über einen Zeitraum von 30 Monaten. Die Daten wurden an 1167 Schüler/innen mittels Fragebögen erhoben. Ergebnisse: Die Wahrscheinlichkeit für die Initiierung des Rauschtrinkens im Beobachtungszeitraum war bei Kindern und Jugendliche, die die Verfügbarkeit von Bier/Wein als hoch einschätzten, im Vergleich zu denen, die sie für gering erachteten, mit einem Chancenverhältnis (Adjustiertes Odds Ratio: AOR) von 1,54 (95 % Konfidenzintervall (KI): 1,14 – 2,09; p = 0,005) signifikant erhöht. Auch die wahrgenommene Verfügbarkeit von Spirituosen stellte sich als signifikanter Prädiktor heraus (AOR = 1,59; 95 % KI: 1,10 – 2,32; p = 0,014). Hier ergab sich weiterhin ein signifikanter Interaktionseffekt mit dem Alter der Kinder und Jugendlichen (AOR = 3,01; 95 % KI: 1,35 – 6,74; p = 0,007). Ein signifikanter Einfluss der wahrgenommenen Verfügbarkeit von Spirituosen konnte lediglich bei älteren Jugendlichen gefunden werden. Schlussfolgerungen: Neben politischen Maßnahmen zur Regulation der objektiven Verfügbarkeit von Alkohol (Mindestbezugsalter, Öffnungszeiten und Dichte von Verkaufsstellen) erscheint im Hinblick auf die subjektive Verfügbarkeit auch die Berücksichtigung des unmittelbaren sozialen Umfeldes für präventive Maßnahmen von Bedeutung zu sein.

A retrospective analysis of psychosocial risk factors modulating adolescent alcohol binge drinking

BACKGROUND/AIMS

Adolescent alcohol binge-induced hospital admissions (BIHAs) are an increasing problem in Europe. We investigated whether psychosocial factors (e.g., drinking situations, drinking occasions and neighborhood unemployment) are associated with particularly risky patterns of alcohol or substance use.

METHOD

We performed a systematic retrospective chart review of all the respective cases in 2003-2008 (n = 586; age range: 12-17 years) from both pediatric hospitals in the city of Dresden, Germany.

RESULTS

The vast majority of adolescent BIHAs were associated with drinking together with peers at weekend parties. Compared to this 'typical' drinking pattern, adolescents drinking 'atypically' (i.e., drinking either alone, to cope or despite the fact that the next day was a school/work day) more often had already used alcohol and illegal substances before and were more often diagnosed with substance use disorders and other mental disorders prior to BIHA. The unemployment rate in the patients' neighborhood was positively related to the incidence proportion of adolescent BIHAs in the respective subdistricts (r(s) = 0.61).

CONCLUSION

Adolescent atypical drinking may indicate an increased risk for the development of alcohol and substance use disorders. This information is quickly accessible and can alert clinicians to initiate psychosocial aftercare; their infrastructure should address the strong relation between BIHA probability and neighborhood unemployment rates.

Current hypotheses on the mechanisms of alcoholism

Chronic use of alcohol results in progressive changes to brain and behavior that often lead to the development of alcohol dependence and alcoholism. Although the mechanisms underlying the development of alcoholism remain to be fully elucidated, diminished executive functioning due to hypoactive prefrontal cortex executive control and hyperactive limbic system anxiety and negative emotion might contribute mechanistically to the shift from experimental use to alcoholism and dependence. In the chapter that follows, behavioral deficits associated with cortical dysfunction and neurodegeneration will be related to the behavioral characteristics of alcoholism (e.g., diminished executive function, impulsivity, altered limbic modulation). We will provide evidence that alterations in cyclic AMP-responsive element binding protein (CREB: neurotrophic) and NF-κB (neuroimmune) signaling contribute to the development and persistence of alcoholism. In addition, genetic predispositions and an earlier age of drinking onset will be discussed as contributing factors to the development of alcohol dependence and alcoholism. Overall chronic ethanol-induced neuroimmune gene induction is proposed to alter limbic and frontal neuronal networks contributing to the development and persistence of alcoholism.