Predictors of subgroups based on maximum drinks per occasion over six years for 833 adolescents and young adults in COGA

Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder

Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.

The collaborative study on the genetics of alcoholism: Sample and clinical data

The collaborative study on the genetics of alcoholism (COGA) is a multi-site, multidisciplinary project with the goal of identifying how genes are involved in alcohol use disorder and related outcomes, and characterizing how genetic risk unfolds across development and in conjunction with the environment and brain function. COGA is a multi-generational family-based study in which probands were recruited through alcohol treatment centers, along with a set of community comparison families. Nearly 18,000 individuals from >2200 families have been assessed over a period of over 30 years with a rich phenotypic battery that includes semi-structured psychiatric interviews and questionnaire measures, along with DNA collection and electrophysiological data on a large subset. Participants range in age from 7 to 97, with many having longitudinal assessments, providing a valuable opportunity to study alcohol use and problems across the lifespan. Here we provide an overview of data collection methods for the COGA sample, and details about sample characteristics and comorbidity. We also review key research findings that have emerged from analyses of the COGA data. COGA data are available broadly to researchers, and we hope this overview will encourage further collaboration and use of these data to advance the field.

Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder

Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.

Contributions of Demand/Withdraw Processes and Alcohol Consumption on Emotional Flooding in Distressed Violent versus Distressed Non-Violent Couples

Purpose

Although alcohol-related intimate partner violence (IPV) is a serious public health problem, the mechanisms underlying this association are poorly understood. For instance, prior research has shown differences in distressed violent (DV) and distressed nonviolent (DNV) couples' demand/withdraw communication and the extent to which they become emotionally flooded (i.e., physiologically aroused) in response to conflict. Additionally, alcohol use is associated with increased demand/withdraw communication, IPV, and emotional flooding. Therefore, the present study sought to clarify the association between demand/withdraw communication and emotional flooding among relationally couples who use alcohol and who do and do not experience IPV.

Methods

Relationally distressed couples (Mage =30.1 years) reported on their physical aggression, demand/withdraw communication, emotional flooding, and total number of drinks during the past six months. Couples were denoted as DV (N = 58) if at least one partner reported IPV and DNV (N = 29) if neither partner reported IPV. Actor-partner interdependence modeling was used to test whether couple type (DV versus DNV) moderates the link between demand/withdraw behavior and emotional flooding.

Results

With one exception, alcohol use was unrelated to any of the processes under investigation in the current study. Moreover, men's and women's report of a woman-demand/man-withdraw pattern and man-demand/woman-withdraw pattern, respectively, were positively associated with each partner's own emotional flooding. Couple type (DV vs DNV) did not moderate these associations.

Conclusions

The present results highlight the need for sensitive measures that can capture the nuanced processes that underlie IPV in couples who use alcohol.

Multiple diverse drinking trajectories among sexual minority women: Unique and joint prediction by minority stress and social influence risk factors

BACKGROUND

Sexual minority populations are at heightened risk for alcohol use disorders compared to heterosexual populations, and these disparities are particularly pronounced for sexual minority women (SMW). Little research has examined the diversity of drinking trajectories among sexual minorities, despite evidence that such trajectories have high predictive utility and are useful in understanding how risk factors may be uniquely associated with specific trajectories.

METHOD

We utilized four waves of data (12 months between waves) from a sample of 1,057 SMW ages 18-25 at Wave 1. The goals were to (a) identify multiple distinct trajectories of alcohol use; (b) examine the predictive utility of these trajectories; and (c) test associations between minority stress (e.g., discrimination) and social influence (e.g., sexual minority community involvement) risk factors and alcohol trajectories.

RESULTS

Using growth mixture modeling, we identified five classes based on drinking patterns at Wave 1 and change over time (stable low, stable high drinking, stable high HED, low increasing, and high decreasing). These classes were differentially associated with Wave 1 levels and changes in alcohol consequences. Minority stressors uniquely predicted a low increasing trajectory, while social influences uniquely predicted a stable high trajectory. Both minority stress and social risk factors predicted high decreasing and stable high HED trajectories.

CONCLUSIONS

Findings indicate that some drinking trajectories among SMW appear similar to those found in the general population, while others appear unique. Results provide insight into how minority stress and social influence risk factors may uniquely and jointly contribute to disparities affecting this population.

Exploration of the Impact of Combining Risk Phenotypes on the Likelihood of Alcohol Problems in Young Adults

AIMS

We tested the hypothesis that high novelty seeking (NS-an externalizing trait), sweet-liking (SL-a phenotype that may reflect processing of hedonic stimuli) and initial insensitivity to the impairing effects of alcohol (SRE-A) act independently and synergistically to increase the likelihood of having alcohol-related problems in young adults.

METHODS

A sample of 145 young adults, ages 18-26, balanced for gender and alcohol use disorders identification test (AUDIT) scores <8 or ≥8 were selected from a prior sample. NS, SL and SRE-A were assessed along with AUDIT score and family history of alcoholism (FH). The effect of phenotypes and their interaction on the likelihood of alcohol problems was assessed.

RESULTS

All three phenotypes contribute to the total AUDIT score. The best-fitting model explaining 35.8% of AUDIT variance includes all three phenotypes and an interaction between NS and SL/sweet-disliking (SDL) status. The addition of FH to the model explains an additional 4% of variance in both models. Classification and regression tree analysis showed that the main phenotype influencing AUDIT score is NS. The SL/SDL phenotype is a strong modifying factor for high NS. SRE-A was shown to be a weak modifier for individuals with low NS.

CONCLUSION

The evidence supports the hypothesis that the presence of multiple alcohol use disorders (AUD) risk phenotypes with different underlying neurobiological mechanisms within an individual (SL, NS and SRE-A) represents a higher likelihood for developing alcohol-related problems and may allow for a graded assessment of risk for AUD and offer the possibility for early intervention strategies.

Gamma oryzanol impairs alcohol-induced anxiety-like behavior in mice via upregulation of central monoamines associated with Bdnf and Il-1β signaling

Adolescent alcohol exposure may increase anxiety-like behaviors by altering central monoaminergic functions and other important neuronal pathways. The present study was designed to investigate the anxiolytic effect of 0.5% γ-oryzanol (GORZ) and its neurochemical and molecular mechanisms under chronic 10% ethanol consumption. Five-week-old ICR male mice received either control (14% casein, AIN 93 M) or GORZ (14% casein, AIN 93 M + 0.5% GORZ) diets in this study. We showed that GORZ could potentially attenuate alcohol-induced anxiety-like behaviors by significantly improving the main behavioral parameters measured by the elevated plus maze test. Moreover, GORZ treatment significantly restored the alcohol-induced downregulation of 5-hydroxytryptophan and 5-hydroxyindole acetic acid in the hippocampus and improved homovanillic acid levels in the cerebral cortex. Furthermore, a recovery increase in the level of 3-methoxy-4-hydroxyphenylglycol both in the hippocampus and cerebral cortex supported the anxiolytic effect of GORZ. The significant elevation and reduction in the hippocampus of relative mRNA levels of brain-derived neurotrophic factor and interleukin 1β, respectively, also showed the neuroprotective role of GORZ in ethanol-induced anxiety. Altogether, these results suggest that 0.5% GORZ is a promising neuroprotective drug candidate with potential anxiolytic, neurogenic, and anti-neuroinflammatory properties for treating adolescent alcohol exposure.

Identifying trajectories of alcohol use in a sample of secondary school students in Ontario and Alberta: longitudinal evidence from the COMPASS study

INTRODUCTION

Despite evidence indicating a rapid progression in use of alcohol during adolescence, little is known about the ways patterns of drinking develop over time. This study investigated patterns of alcohol use within a cohort of youth in Ontario and Alberta and the probability of changes between patterns.

METHODS

The sample consists of two-year linked longitudinal data (school year 2013/14 to 2014/15) from 19 492 students in Grades 9 to 12 in 89 secondary schools across Ontario and Alberta, Canada, who participated in the COMPASS study. The latent class analysis used two self-reported items about the frequency of drinking (measured as none, monthly, weekly, or daily use) and the frequency of binge drinking (measured as none, less than or once a month, 2-4 times a month, or more than once week) to characterize patterns of alcohol use. The effects of gender, ethnicity and cannabis and cigarette use on alcohol use patterns were examined.

RESULTS

The study identified four drinking patterns: non-drinker, periodic drinker (reported monthly drinking and no binge drinking), low-risk drinker (reported monthly drinking and limited binge drinking) and high-risk regular drinker (reported drinking 1-3 times a week and binge drinking 2-4 times a month). Non-drinker was the most prevalent pattern at baseline (55.1%) and follow-up (39.1%). Periodic drinkers had the highest likelihood of an increase in alcohol consumption, with 40% moving to the low-risk pattern. A notable proportion of participants returned to a lower severity pattern or transitioning out of drinking.

CONCLUSION

There are four distinct youth alcohol-use patterns. The high probability of transitioning to drinking during the secondary school years suggests the need for preventive interventions in earlier stages of use, before drinking becomes habitual.

Do Classes of Polysubstance Use in Adolescence Differentiate Growth in Substances Used in the Transition to Young Adulthood?

BACKGROUND

Past studies have differentiated classes of polysubstance use in adolescence, however, the associations of adolescent polysubstance use classes with longitudinal substance use trajectories from adolescence to young adulthood have not been studied.

OBJECTIVE

The current study examined substance use classes during adolescence and longitudinal trajectories of each substance used across the transition to young adulthood.

METHOD

Data were collected biennially from 662 youth and followed 10 years across six measurement assessments. Using baseline data (T1), latent class analysis was used to identify classes of polysubstance use (cigarette, alcohol, marijuana, and illicit drug use) during adolescence. Using T2 through T6 data, we fit latent growth models for cigarette, alcohol, marijuana, and illicit drug use to examine longitudinal trajectories of each substance used by class.

RESULTS

A three-class model fit the data best and included a poly-use class, that had high probabilities of use among all substances, a co-use class, that had high probabilities of use among alcohol and marijuana, and a low-use class that had low probabilities of use among all substances. We then examined trajectories of each substance used by class. Strong continuity of substance use was found by class across 14 years. Additionally, for some substances, higher average levels of use of at age 14 were associated with change in growth of other substances used over time. Conclusions/Importance: Efforts that only target a single drug type may be missing an important opportunity to reduce the use and subsequent consequences related to the use of multiple substances.

Altered Brain Developmental Trajectories in Adolescents After Initiating Drinking

OBJECTIVE

The authors sought evidence for altered adolescent brain growth trajectory associated with moderate and heavy alcohol use in a large national, multisite, prospective study of adolescents before and after initiation of appreciable alcohol use.

METHOD

This study examined 483 adolescents (ages 12-21) before initiation of drinking and 1 and 2 years later. At the 2-year assessment, 356 participants continued to meet the study's no/low alcohol consumption entry criteria, 65 had initiated moderate drinking, and 62 had initiated heavy drinking. MRI was used to quantify regional cortical and white matter volumes. Percent change per year (slopes) in adolescents who continued to meet no/low criteria served as developmental control trajectories against which to compare those who initiated moderate or heavy drinking.

RESULTS

In no/low drinkers, gray matter volume declined throughout adolescence and slowed in many regions in later adolescence. Complementing gray matter declines, white matter regions grew at faster rates at younger ages and slowed toward young adulthood. Youths who initiated heavy drinking exhibited an accelerated frontal cortical gray matter trajectory, divergent from the norm. Although significant effects on trajectories were not observed in moderate drinkers, their intermediate position between no/low and heavy drinkers suggests a dose effect. Neither marijuana co-use nor baseline volumes contributed significantly to the alcohol effect.

CONCLUSIONS

Initiation of drinking during adolescence, with or without marijuana co-use, disordered normal brain growth trajectories. Factors possibly contributing to abnormal cortical volume trajectories include peak consumption in the past year and family history of alcoholism.

Effects of adolescent alcohol exposure on stress-induced reward deficits, brain CRF, monoamines and glutamate in adult rats

BACKGROUND

Adolescent alcohol exposure may increase depression vulnerability in adulthood by increasing the anhedonic response to stress.

METHODS

Male Wistar rats (postnatal days 28-53) were exposed to binge-like adolescent intermittent ethanol (AIE) or water. In adulthood, rats were exposed to social defeat, consisting of daily confrontations with an aggressive conspecific, followed by testing of brain reward function in a discrete-trial current-intensity intracranial self-stimulation procedure for 10 consecutive days. Neurochemistry and corticotropin-releasing factor (CRF) and CRF receptor 1 (CRFR1) mRNA levels were assessed in corticolimbic brain areas on day 11 of social defeat stress.

RESULTS

Social defeat elevated reward thresholds in both AIE- and water-exposed rats indicating stress-induced anhedonia. However, AIE-exposed rats were more likely to show threshold elevations after repeated stress compared to water-exposed rats. AIE exposure decreased CRF mRNA levels in the nucleus accumbens and increased CRFR1 mRNA levels in the prefrontal cortex, while stress increased CRF mRNA levels in the central amygdala. In the caudate putamen, AIE exposure decreased dopamine turnover, while stress increased glutamate and serotonin metabolism and turnover.

CONCLUSIONS

These results demonstrate increased risk of repeated stress-induced anhedonia after AIE exposure, an effect that may be due to alterations in brain CRF and dopamine systems. These results suggest that the increased rates of depression reported in people with a history of adolescent alcohol exposure may be related to alterations in brain reward and stress systems that may contribute to increased stress-induced anhedonia.

Predictors of Patterns of Alcohol-Related Blackouts Over Time in Youth From the Collaborative Study of the Genetics of Alcoholism: The Roles of Genetics and Cannabis

OBJECTIVE

Alcohol-related blackouts (ARBs) are anterograde amnesias related to heavy alcohol intake seen in about 50% of drinkers. Although a major determinant of ARBs relates to blood alcohol concentrations, additional contributions come from genetic vulnerabilities and possible impacts of cannabis use disorders (CUDs). We evaluated relationships of genetics and cannabis use to latent class trajectories of ARBs in 829 subjects from the Collaborative Study of the Genetics of Alcoholism (COGA).

METHOD

The number of ARBs experienced every 2 years from subjects with average ages of 18 to 25 were entered into a latent class growth analysis in Mplus, and resulting class membership was evaluated in light of baseline characteristics, including CUDs. Correlations of number of ARBs across assessments were also compared for sibling pairs versus unrelated subjects.

RESULTS

Latent class growth analysis identified ARB-based Classes 1 (consistent low = 42.5%), 2 (moderate low = 28.3%), 3 (moderate high = 22.9%), and 4 (consistent high = 6.3%). A multinomial logistic regression analysis within latent class growth analysis revealed that baseline CUDs related most closely to Classes 3 and 4. The number of ARBs across time correlated .23 for sibling pairs and -.10 for unrelated subjects.

CONCLUSIONS

Baseline CUDs related to the most severe latent ARB course over time, even when considered along with other trajectory predictors, including baseline alcohol use disorders and maximum number of drinks. Data indicated significant roles for genetic factors for alcohol use disorder patterns over time. Future research is needed to improve understanding of how cannabis adds to the ARB risk and to find genes that contribute to risks for ARBs among drinkers.

Sex and Adolescent Ethanol Exposure Influence Pavlovian Conditioned Approach

BACKGROUND

Alcohol use among adolescents is widespread and a growing concern due to long-term behavioral deficits, including altered Pavlovian behavior, that potentially contribute to addiction vulnerability. We tested the hypothesis that adolescent intermittent ethanol (AIE) exposure alters Pavlovian behavior in males and females as measured by a shift from goal-tracking to sign-tracking. Additionally, we investigated GLT-1, an astrocytic glutamate transporter, as a potential contributor to a sign-tracking phenotype.

METHODS

Male and female Sprague-Dawley rats were exposed to AIE (5 g/kg, intragastric) or water intermittently 2 days on and 2 days off from postnatal day (P) 25 to 54. Around P70, animals began 20 daily sessions of Pavlovian conditioned approach (PCA), where they learned that a cue predicted noncontingent reward delivery. Lever pressing indicated interaction with the cue, or sign-tracking, and receptacle entries indicated approach to the reward delivery location, or goal-tracking. To test for effects of AIE on nucleus accumbens (NAcc) excitatory signaling, we isolated membrane subfractions and measured protein levels of the glutamate transporter GLT-1 after animals completed behavior as a measure of glutamate homeostasis.

RESULTS

Females exhibited elevated sign-tracking compared to males with significantly more lever presses, faster latency to first lever press, and greater probability to lever press in a trial. AIE significantly increased lever pressing while blunting goal-tracking, as indicated by fewer cue-evoked receptacle entries, slower latency to receptacle entry, and lower probability to enter the receptacle in a trial. No significant sex-by-exposure interactions were observed in sign- or goal-tracking metrics. Moreover, we found no significant effects of sex or exposure on membrane GLT-1 expression in the NAcc.

CONCLUSIONS

Females exhibited enhanced sign-tracking compared to males, while AIE decreased goal-tracking compared to control exposure. Our findings support the hypothesis that adolescent binge ethanol can shift conditioned behavior from goal- to cue-directed in PCA, especially in females.

Longitudinal Conjoint Patterns of Alcohol and Tobacco Use Throughout Emerging Adulthood

BACKGROUND

The concurrent use of alcohol and tobacco has a multiplicative effect on both social and physical consequences. While it is known that alcohol and tobacco use are strongly correlated in emerging adulthood, there is significant individual variability in use. However, little research has examined how patterns of concurrent use are related over time.

OBJECTIVES

The current study explores these longitudinal conjoint trajectories, as well as the associated sociodemographic factors.

METHODS

We used sequential latent class growth analysis to explore the co-occurring longitudinal patterns of recent alcohol and tobacco use across emerging adulthood (10 data collection periods, 2004-2009) with a diverse sample of 2,244 college students (60% female; 54% White).

RESULTS

Twenty distinct patterns of conjoint alcohol and tobacco use were found. There was more variation in tobacco use trajectories among alcohol users than variation in alcohol trajectories among tobacco users. Using multinomial logistic regression models we determined the impact of sociodemographic characteristics on classification into each conjoint pattern versus the normative trajectory (Abstaining tobacco/Low alcohol). Male gender, White race, fraternity/sorority affiliation, and higher family income were significantly associated with riskier conjoint trajectory patterns. Conclusions/Importance: Findings highlight the diversity of alcohol and tobacco use behaviors across emerging adulthood. The low variation in alcohol use among tobacco users indicates that tobacco use is a significant risk factor for heavier drinking. A better understanding of the covarying use of these two ubiquitous substances may provide new avenues for preventing and reducing the use of both.

Adolescent Alcohol Exposure Persistently Impacts Adult Neurobiology and Behavior

Adolescence is a developmental period when physical and cognitive abilities are optimized, when social skills are consolidated, and when sexuality, adolescent behaviors, and frontal cortical functions mature to adult levels. Adolescents also have unique responses to alcohol compared with adults, being less sensitive to ethanol sedative-motor responses that most likely contribute to binge drinking and blackouts. Population studies find that an early age of drinking onset correlates with increased lifetime risks for the development of alcohol dependence, violence, and injuries. Brain synapses, myelination, and neural circuits mature in adolescence to adult levels in parallel with increased reflection on the consequence of actions and reduced impulsivity and thrill seeking. Alcohol binge drinking could alter human development, but variations in genetics, peer groups, family structure, early life experiences, and the emergence of psychopathology in humans confound studies. As adolescence is common to mammalian species, preclinical models of binge drinking provide insight into the direct impact of alcohol on adolescent development. This review relates human findings to basic science studies, particularly the preclinical studies of the Neurobiology of Adolescent Drinking in Adulthood (NADIA) Consortium. These studies focus on persistent adult changes in neurobiology and behavior following adolescent intermittent ethanol (AIE), a model of underage drinking. NADIA studies and others find that AIE results in the following: increases in adult alcohol drinking, disinhibition, and social anxiety; altered adult synapses, cognition, and sleep; reduced adult neurogenesis, cholinergic, and serotonergic neurons; and increased neuroimmune gene expression and epigenetic modifiers of gene expression. Many of these effects are specific to adolescents and not found in parallel adult studies. AIE can cause a persistence of adolescent-like synaptic physiology, behavior, and sensitivity to alcohol into adulthood. Together, these findings support the hypothesis that adolescent binge drinking leads to long-lasting changes in the adult brain that increase risks of adult psychopathology, particularly for alcohol dependence.

Adolescent alcohol exposure decreased sensitivity to nicotine in adult Wistar rats

Many adolescents engage in heavy alcohol use. Limited research in humans indicates that adolescent alcohol use predicts adult tobacco use. The present study investigated whether adolescent intermittent ethanol (AIE) exposure alters nicotine sensitivity in adulthood. Adolescent male Wistar rats (postnatal day 28-53) were exposed to AIE exposure that consisted of 5 g/kg of 25 percent ethanol three times per day in a 2 days on/2 days off regimen. Control rats received water with the same exposure regimen. In adulthood, separate groups of rats were tested for nicotine intravenous self-administration (IVSA), drug discrimination and conditioned taste aversion (CTA). The dose-response function for nicotine IVSA under a fixed-ratio schedule of reinforcement was similar in AIE-exposed and control rats. However, AIE-exposed rats self-administered less nicotine at the lowest dose, suggesting that low-dose nicotine was less reinforcing in AIE-exposed, compared with control rats. AIE-exposed rats self-administered less nicotine under a progressive-ratio schedule, suggesting decreased motivation for nicotine after AIE exposure. The discriminative stimulus effects of nicotine were diminished in AIE-exposed rats compared with control rats. No group differences in nicotine CTA were observed, suggesting that AIE exposure had no effect on the aversive properties of nicotine. Altogether, these results demonstrate that AIE exposure decreases sensitivity to the reinforcing, motivational and discriminative properties of nicotine while leaving the aversive properties of nicotine unaltered in adult rats. These findings suggest that drinking during adolescence may result in decreased sensitivity to nicotine in adult humans, which may in turn contribute to the higher rates of tobacco smoking.

Population Behavior Patterns in Response to the Risk of Influenza A(H7N9) in Hong Kong, December 2013-February 2014

Background

A novel avian influenza A(H7N9) virus, first identified in Mainland China in February and March 2013, caused an outbreak in humans in April and May, 2013. Closure of live poultry markets in some affected cities dramatically reduced numbers of cases during summer of 2013, but the epidemic resurged during the winter 2013–14, increasing reported cases to 393 in Mainland China as of 30 March 2014.

Purpose

The study aimed to explore population behavior patterns responding to an epidemic of influenza A(H7N9) virus.

Method

Three cross-sectional surveys were conducted among 1000, 680, and 1011 respondents in December 2013, January 2014, and February 2014, with response rates of 68.0, 64.4, and 66.6 %, respectively, in Hong Kong. Adults were recruited and interviewed using random digit-dialing telephone survey. Latent class analysis was employed to explore heterogeneity in protective behavior patterns across the three surveys. Multinomial regression models were developed to determine factors associated with latent class membership.

Results

Three comparable latent classes were identified across the three surveys: Moderate hygiene compliance (Class 1), High hygiene compliance (Class 2), and Vigilance (Class 3). The prevalence of Class 1 was 48–52 % across the three surveys while Class 3 prevalence increased significantly from 13 % in the Dec-2013 survey to 20 % in the Feb-2014 survey. Compared with Class 1, Class 3 were more likely to be female, older, better educated, married, perceive higher susceptibility to H7N9, attribute greater severity to H7N9, report higher current worry, and anticipated worry about H7N9 infection.

Conclusion

The three classes reflect different levels of adoption of protection and thereby may have different levels of vulnerability toward contracting H7N9 infection. It appears that as the epidemic intensifies, Class 2 (Good hygiene compliance) members are likely to transfer to Class 3 (Vigilance) while Class 1 (Moderate hygiene compliance) could be unchanged. The young, mostly single males and those with lower educational achievement represent a group for whom public health messages need to be targeted.

A Preliminary Prospective Study of an Escalation in 'Maximum Daily Drinks', Fronto-Parietal Circuitry and Impulsivity-Related Domains in Young Adult Drinkers

Excessive alcohol use in young adults is associated with greater impulsivity and neurobiological alterations in executive control systems. The maximum number of drinks consumed during drinking occasions ('MaxDrinks') represents a phenotype linked to vulnerability of alcohol use disorders, and an increase, or 'escalation', in MaxDrinks may be indicative of greater risk for problematic drinking. Thirty-six young adult drinkers performed a Go/No-Go task during fMRI, completed impulsivity-related assessments, and provided monthly reports of alcohol use during a 12-month follow-up period. Participants were characterized by MaxDrinks at baseline and after follow-up, identifying 18 escalating drinkers and 18 constant drinkers. Independent component analysis was used to investigate functional brain networks associated with response inhibition, and relationships with principal component analysis derived impulsivity-related domains were examined. Greater baseline MaxDrinks was associated with an average reduction in the engagement of a right-lateralized fronto-parietal functional network, while an escalation in MaxDrinks was associated with a greater difference in fronto-parietal engagement between successful inhibitions and error trials. Escalating drinkers displayed greater impulsivity/compulsivity-related domain scores that were positively associated with fronto-parietal network engagement and change in MaxDrinks during follow-up. In young adults, an escalating MaxDrinks trajectory was prospectively associated with altered fronto-parietal control mechanisms and greater impulsivity/compulsivity scores. Continued longitudinal studies of MaxDrinks trajectories, functional network activity, and impulsivity/compulsivity-related features may lend further insight into an intermediate phenotype vulnerable for alcohol use and addictive disorders.

The impact of focusing a program to prevent heavier drinking on a pre-existing phenotype, the low level of response to alcohol

BACKGROUND

Heavy drinking is common during transitions from high school to college. Optimal programs for diminishing risks for high alcohol consumption often tailor the approach to the specific needs of students. This study describes the results of an Internet-based prevention protocol that tailors the information to the risk associated with a pre-existing phenotype, the Low level of Response (Low LR) to alcohol.

METHODS

Using stratified random assignment, 454 freshmen with Low and High LR values were assigned to 2 education groups (LR-based where all examples were given the context of the Low LR model of heavy drinking or a State Of The Art (SOTA) Group where the same lessons were taught but without an emphasis on LR) or a no-intervention Control Group. Individuals in the 2 education groups viewed 50-minute online videos once per week for 4 weeks. Changes in drinking patterns were assessed at Baseline, 4 weeks, and 8 weeks using a 2 (LR status) by 3 (education group) by 3 (time points) analysis of variance, with additional tests for ethnicity and sex.

RESULTS

Low LR participants tended to decrease their usual (p < 0.06) and maximum (p < 0.05) drinks per occasion most prominently when assigned to the LR-based protocol, while those with High LRs improved more in the SOTA Group. The most robust differences were seen when controlling for ethnicity. The effect sizes were small to medium.

CONCLUSIONS

These results support the advantages of carrying out prevention via the Internet and in tailoring the approach to a pre-existing phenotype.

Latent trajectory classes for alcohol-related blackouts from age 15 to 19 in ALSPAC

BACKGROUND

Alcohol-related blackouts (ARBs) are reported by ~50% of drinkers. While much is known about the prevalence of ARBs in young adults and their cross-sectional correlates, there are few prospective studies regarding their trajectories over time during mid-adolescence. This paper reports latent trajectory classes of ARBs between age 15 and 19, along with predictors of those patterns.

METHODS

Latent class growth analysis (LCGA) was used to evaluate the pattern of occurrence of ARBs across 4 time points for 1,402 drinking adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC). Multinomial regression analyses evaluated age-15 demography, substance-related items, externalizing characteristics, and estimated peer substance use as predictors of latent class membership.

RESULTS

ARBs were reported at age 15 in 30% and at age 19 in 74% of these subjects. Four latent trajectory classes were identified: Class 1 (5.1%) reported no blackouts; for Class 2 (29.5%), ARBs rapidly increased with age; for Class 3 (44.9%), blackouts slowly increased; and for Class 4 (20.5%), ARBs were consistently reported. Using Class 2 (rapid increasers) as the reference, predictors of class membership included female sex, higher drinking quantities, smoking, externalizing characteristics, and estimated peer substance involvement (pseudo R(2)  = 0.22).

CONCLUSIONS

ARBs were common and repetitive in these young subjects, and predictors of their trajectories over time involved multiple domains representing diverse characteristics.