The self-rating of the effects of alcohol questionnaire as a predictor of alcohol-related outcomes in 12-year-old subjects

Alcohol Consumption Questionnaire: Scale development in a sample of Mexican American young adults and association with ADH7

BACKGROUND

To understand why some individuals who develop alcohol use disorders (AUD) first begin to drink heavily, a number of scales have been developed that index aspects of alcohol craving and restraint from drinking. We developed a new measure called the Alcohol Consumption Questionnaire (ACQ), based in part on items modified from scales used to index binge eating because there are data to suggest that binge eating and binge drinking may share common antecedents. We present an initial validity study using data from a sample of Mexican Americans.

METHODS

Data were from 699 Mexican American young adults in San Diego County, CA. A subsample (n=60) had short-term test-retest data. Factor analysis and reliability assessment guided item reduction. Item response theory (IRT) analyses quantified item severity and identified questions with differential item functioning (DIF). Logistic regression assessed associations of mean scale scores with AUD, adjusting for key demographics, alcohol expectancies and subjective response to alcohol. We also examined associations with a protective genetic variant downstream from the alcohol dehydrogenase 7 gene (ADH7).

RESULTS

The scale was reduced from 20 to 14 questions, which can be summarized by a single overall score (Cronbach's alpha=0.896) or by two sub-scores (Consumption: 12 items, Cronbach's alpha=0.896; Enjoyment: 2 items, Cronbach's alpha=0.780). Test-retest reliability was very high (0.80-0.98) in this sample. The overall ACQ score and each subdomain score were strongly associated with AUD (ORs= 5.95 mild; 11.41 moderate; 48.56 severe) and family history of AUD. Respondents with the protective genetic variant had significantly lower overall ACQ scores (p<.001).

CONCLUSION

The ACQ is a novel measure of alcohol consumption with strong relationships with both the AUD phenotype and ADH7 gene variants in a sample of Mexican American young adults.

Retrospective self-reports of sensitivity to the effects of alcohol: Trait-like stability and concomitant changes with alcohol involvement

OBJECTIVE

Lower sensitivity to the acute effects of alcohol is known to confer risk for the development of alcohol use disorder. Alcohol sensitivity, or level of response to alcohol's subjective effects, is heritable but also can change as a result of persistent alcohol exposure (i.e., acquired tolerance). Here, we examined how changes over time in four indices of alcohol involvement affected scores on two validated, retrospective self-report measures of alcohol response-the Self-Rating of the Effects of Alcohol (SRE) form and the Alcohol Sensitivity Questionnaire (ASQ)-in a sample of emerging adult drinkers.

METHOD

Participants (N = 173; Mage = 19.5 years; 60% assigned female at birth) completed the ASQ, SRE, and measures of alcohol use and problems at two time points separated by a median of 0.77 years (range: 0.30-2.54 years).

RESULTS

Multiple linear regression showed that increases in drinking over this period accounted for increases in SRE and ASQ scores (i.e., in reported numbers of drinks needed to experience subjective effects of alcohol). Increased drinking accounted for more variance in the number of drinks needed to experience lighter drinking versus heavier drinking effects, and increases in the number of drinks consumed per occasion had a larger effect than did changes in total numbers of drinks consumed, number of binge-drinking occasions, or drinking-related problems.

CONCLUSIONS

Findings suggest that both SRE and ASQ capture some stable, trait-like variability in alcohol response as well as some state-dependent, within-person variability in alcohol response acquired through increases in alcohol involvement. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Patterns and Correlates of Polysubstance Use Among Individuals With Severe Alcohol Use Disorder

AIM

The present study examined patterns and correlates of polysubstance use among individuals with severe alcohol use disorder (AUD).

METHODS

Participants were 2785 individuals (63% female; mean age = 43 years, range = 18-78 years) from the Genes, Addiction and Personality Study. All participants met lifetime criteria for severe AUD (6+ symptoms). We used latent class analysis to identify patterns of frequency of lifetime use for cigarettes, marijuana, cocaine, stimulants, sedatives, opioids and hallucinogens. A variety of demographic and behavioral correlates of latent class membership were tested in univariable and multivariable models.

RESULTS

A five-class solution was selected: extended range polysubstance use (24.5%); cigarette and marijuana use (18.8%); 'testers,' characterized by high probabilities of smoking 100 or more cigarettes, using marijuana 6+ times, and trying the remaining substances 1-5 times (12.3%); moderate range polysubstance use (17.1%) and minimal use (reference class; 27.3%). In univariable analyses, all potential correlates were related to latent class membership. In the multivariable model, associations with gender, race/ethnicity, age of onset for alcohol problems, dimensions of impulsivity, depressive symptoms, antisocial behavior and family history density of alcohol problems remained significant, though the pattern and strength of associations differed across classes. For instance, sensation-seeking, lack of premeditation and family history were uniquely associated with membership in the extended range polysubstance use class.

CONCLUSION

Patterns of polysubstance use are differentially related to demographic and behavioral factors among individuals with severe AUD. Assessing use across multiple substances may inform the selection of targets for treatment and prevention.

Interoception and alcohol: Mechanisms, networks, and implications

Interoception refers to the perception of the internal state of the body and is increasingly being recognized as an important factor in mental health disorders. Drugs of abuse produce powerful interoceptive states that are upstream of behaviors that drive and influence drug intake, and addiction pathology is impacted by interoceptive processes. The goal of the present review is to discuss interoceptive processes related to alcohol. We will cover physiological responses to alcohol, how interoceptive states can impact drinking, and the recruitment of brain networks as informed by clinical research. We also review the molecular and brain circuitry mechanisms of alcohol interoceptive effects as informed by preclinical studies. Finally, we will discuss emerging treatments with consideration of interoception processes. As our understanding of the role of interoception in drug and alcohol use grows, we suggest that the convergence of information provided by clinical and preclinical studies will be increasingly important. Given the complexity of interoceptive processing and the multitude of brain regions involved, an overarching network-based framework can provide context for how focused manipulations modulate interoceptive processing as a whole. In turn, preclinical studies can systematically determine the roles of individual nodes and their molecular underpinnings in a given network, potentially suggesting new therapeutic targets and directions. As interoceptive processing drives and influences motivation, emotion, and subsequent behavior, consideration of interoception is important for our understanding of processes that drive ongoing drinking and relapse.

Cross-sectional and prospective associations of drinking characteristics with scores from the Self-Report of the Effects of Alcohol questionnaire and findings from alcohol challenges

BACKGROUND

Data from 2 generations of participants in the San Diego Prospective Study (SDPS) were used to compare cross-sectional and prospective relationships of 5 measures of the low level of response (low LR) to alcohol to 2 key alcohol-related outcomes.

METHODS

The analyses used data from 373 SDPS male probands and 158 male and female offspring of these individuals to evaluate relationships of 5 LR measures to the prior 5-year maximum drinks per occasion and the number of 11 DSM-IV alcohol use disorder (AUD) criteria experienced. Probands' LR measures included responses to alcohol challenges administered 15 years previously, and ratings for both generations included measures of the number of standard drinks during four periods: the first five times of drinking (SRE-5), the prior three drinking months (SRE-3), the period of heaviest drinking (SRE-H), and a total average across all time frames (SRE-T). Analyses included zero-order correlations, correlations using covariates, and hierarchical multiple regression analyses.

RESULTS

All 5 LR measures were correlated with aspects of maximum drinks and the number of AUD criteria, but the most robust results were seen for SRE-3 and maximum drinks. Correlations were less consistent for SRE-5, a measure more closely related to outcomes in the offspring. Hierarchical regression analyses supported most of these conclusions and showed that alcohol challenge-based LRs added significant information regarding maximum drinks even when evaluated with SRE values. The close correlation between SRE-H and SRE-T argues against the need for studies to include both measures. The patterns of results were similar irrespective of whether covariates were included.

CONCLUSIONS

There were significant correlations of maximum drinks and the number of AUD criteria with findings from prior alcohol challenges and all SRE scores. Challenges and SRE reports are related but not identical LR measures. All SRE scores, including SRE-5, offered useful information regarding subsequent drinking behavior.

Influence of Cannabinoid Receptor 1 Genetic Variants on the Subjective Effects of Smoked Cannabis

As many jurisdictions consider relaxing cannabis legislation and usage is increasing in North America and other parts of the world, there is a need to explore the possible genetic differences underlying the subjective effects of cannabis. This pilot study investigated specific genetic variations within the cannabinoid receptor 1 (CNR1) gene for association with the subjective effects of smoked cannabis. Data were obtained from a double-blinded, placebo-controlled clinical trial studying the impact of cannabis intoxication on driving performance. Participants randomized to the active cannabis group who consented to secondary genetic analysis (n = 52) were genotyped at the CNR1 rs1049353 and rs2023239 polymorphic areas. Maximum value and area under the curve (AUC) analyses were performed on subjective measures data. Analysis of subjective effects by genotype uncovered a global trend towards greater subjective effects for rs1049353 T-allele- and rs2023239 C-allele-carrying subjects. However, significant differences attributed to allelic identity were only documented for a subset of subjective effects. Our findings suggest that rs1049353 and rs2023239 minor allele carriers experience augmented subjective effects during acute cannabis intoxication.

Relationship between level of response to alcohol and acute tolerance

BACKGROUND

A low level of response (low LR) to alcohol correlates with the later development of alcohol-related problems. Although some of the underpinnings of LR are understood, little is known about the potential relationship between LR and acute tolerance. The current analyses tested the hypothesis that a low LR will be explained in part by more intense acute tolerance to alcohol during a drinking session.

METHODS

Data were generated through a reanalysis of data from 120 individuals who were 18- to 25-year-old, sex-matched pairs of low and high LR drinkers who at baseline did not meet criteria for an alcohol use disorder. Each subject participated in an oral alcohol challenge in which they consumed about 0.7 ml ethanol per kg and acute tolerance was measured as the differences in alcohol's effects at similar breath alcohol levels (BrACs) during the rising and falling breath alcohol concentration (BrAC) curve. Measures included aspects of the Subjective High Assessment Scale (SHAS) and body sway.

RESULTS

Contrary to our hypothesis, but similar to results with other alcohol measures, acute tolerance was significantly attenuated in low LR compared with high LR individuals on most SHAS scores. Neither LR group demonstrated acute tolerance to alcohol for sleepiness or body sway. Men and women did not differ on any of these measures.

CONCLUSION

These data do not support a role of acute tolerance in the low LR to alcohol as measured by subjective feelings of intoxication or body sway in these subjects, findings that were similar across males and females. In addition, consistent with the literature, the analyses demonstrated differences across measures such that acute tolerance was observed for most measures of subjective effects but not for body sway. Among the subjective effects, acute tolerance was observed for alcohol's intoxicating effect but not for feeling sleepy.

Effects of alcohol sensitivity on alcohol-induced blackouts and passing out: An examination of the alcohol sensitivity questionnaire among underage drinkers

BACKGROUND

The role of alcohol sensitivity in the experience of blacking out and passing out has not been well established. Here, we examined the relation between individual differences in alcohol sensitivity (i.e., numbers of drinks required to experience various effects of alcohol) and reports of blacking out and passing out in the past year.

METHODS

Participants (925 healthy, underage college student drinkers) completed the Alcohol Sensitivity Questionnaire (ASQ) and reported on their past year blacking out and passing out experiences.

RESULTS

The fit of the ASQ's 2-factor structure was fair (CFI = 0.90, RMSEA = 0.09) in this sample of underage drinkers. In unadjusted models, higher ASQ scores (i.e., requiring more drinks to experience effects, indicating lower alcohol sensitivity) were associated with experiencing more blackouts (IRR = 1.68 [1.31-2.15]) and passing out (IRR = 2.25 [1.59-3.18]) in the past year. After controlling for typical consumption, however, higher ASQ scores were associated with fewer past-year blackouts (IRR = 0.76 [0.60-0.98]). Total ASQ scores moderated the relationship between typical alcohol consumption and blackout occurrence (interaction IRR = 0.96 [0.93-0.98]), but not passing out occurrence (interaction IRR = 0.95 [0.89-1.01]), with the quantity of alcohol consumed more strongly associated with blackout occurrence among higher-sensitivity than lower-sensitivity drinkers.

CONCLUSIONS

These findings are consistent with prior work suggesting that low sensitivity may act as a paradoxical risk factor for certain heavy drinking effects, contributing to higher levels of alcohol consumption and more frequent negative consequences while also conferring protection (relative to high-sensitivity peers) at a given level of alcohol exposure.

Individual differences in biological regulation: Predicting vulnerability to drug addiction, obesity, and other dysregulatory disorders

Physiological regulation is so fundamental to survival that natural selection has greatly favored the evolution of robust regulatory systems that use both reactive and preemptive responses to mitigate the disruptive impact of biological and environmental challenges on physiological function. In good health, robust regulatory systems provide little insight into the typically hidden complex array of sensor-effector interactions that accomplish successful regulation. Numerous health disorders have been traced to defective regulatory mechanisms, and generations of scientists have worked to discover ways to correct these defects and restore normal physiological function. Despite progress, numerous chronic health disorders remain resistant to treatment, and indeed for some disorders the incidence is increasing. We propose that an individual's susceptibility to acquire certain persistent dysregulatory disorders can be traced to interindividual variation in how that individual's regulatory system responds to challenges. Preexisting reliable individual differences among regulatory systems are typically unrecognized until appropriate regulatory challenges (e.g., exposure to a drug of abuse) lead to dysregulation (e.g., drug addiction). Specific characteristics of an individual's regulatory responsiveness may include etiological factors that participate in the acquisition, escalation and maintenance of health disorders characterized by dysregulation. By appropriately challenging a healthy individual's regulatory systems to identify its underlying characteristics, it is possible to ascertain whether an individual has an elevated risk for acquiring a dysregulated health condition and thereby enable strategies designed to prevent, rather than treat, the condition. This model is applied to drug addiction, and in addition we relate this approach to other dysregulated conditions such as obesity. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Frequent intoxication and alcohol tolerance in adolescence: associations with psychiatric disorders in young adulthood

AIMS

To assess the associations of intoxication frequency and number of drinks needed to become intoxicated in mid-adolescence with onset of psychiatric disorders in early adulthood.

DESIGN, SETTING AND PARTICIPANTS

Prospective cohort study in Northern Finland, with people from the Northern Finland Birth Cohort 1986 who self-reported adolescent alcohol use: 6548 subjects (69.4% of the original sample). Data on alcohol use were collected using questionnaires at ages 15-16 years.

MEASUREMENTS

Outcomes were any non-organic psychosis, mood disorder, anxiety disorder, any substance use disorder (SUD) and all the studied psychiatric disorders in early adulthood gathered from nation-wide health care, pension and insurance registers. Number of drinks needed to become intoxicated was categorized into three classes: (1) no alcohol use or intoxication, and (2) low and (3) high alcohol tolerance (more than seven/nine drinks for females/males) groups. Similarly, intoxication frequency was divided into three classes: (1) never, (2) one to two times and (3) three or more times during the past 30 days. Information regarding gender, family type, other drug use, psychopathology using Youth Self-Report (YSR) total score and parental psychiatric disorders were used as covariates.

FINDINGS

In the multivariable analyses, both low [odds ratio (OR) = 3.0, 95% confidence interval (CI) = 1.3-6.7, P-value = 0.009] and high (OR = 4.4, 95% CI = 1.8-11.1, P-value = 0.001) alcohol tolerance were associated with increased risk of SUD. More frequent intoxication was associated with increased frequency of SUD (OR = 3.9, 95% CI = 2.0-7.3, P-value < 0.001) and mood disorder (OR = 1.6, 95% CI = 1.1-2.3, P-value = 0.008). The latter was attenuated after adjusting with concurrent psychopathology (YSR) and other drug use.

CONCLUSIONS

Both higher alcohol tolerance and frequent intoxication in adolescence appear to be associated with increased risk of future substance use disorder.

Genome-wide association studies of the self-rating of effects of ethanol (SRE)

The level of response (LR) to alcohol as measured with the Self-Report of the Effects of Alcohol Retrospective Questionnaire (SRE) evaluates the number of standard drinks usually required for up to four effects. The need for a higher number of drinks for effects is genetically influenced and predicts higher risks for heavy drinking and alcohol problems. We conducted genome-wide association study (GWAS) in the African-American (COGA-AA, N = 1527 from 309 families) and European-American (COGA-EA, N = 4723 from 956 families) subsamples of the Collaborative Studies on the Genetics of Alcoholism (COGA) for two SRE scores: SRE-T (average of first five times of drinking, the period of heaviest drinking, and the most recent 3 months of consumption) and SRE-5 (the first five times of drinking). We then meta-analyzed the two COGA subsamples (COGA-AA + EA). Both SRE-T and SRE-5 were modestly heritable (h2 : 21%-31%) and genetically correlated with alcohol dependence (AD) and DSM-IV AD criterion count (rg : 0.35-0.76). Genome-wide significant associations were observed (SRE-T: chromosomes 6, rs140154945, COGA-EA P = 3.30E-08 and 11, rs10647170, COGA-AA+EA P = 3.53E-09; SRE-5: chromosome13, rs4770359, COGA-AA P = 2.92E-08). Chromosome 11 was replicated in an EA dataset from the National Institute on Alcohol Abuse and Alcoholism intramural program. In silico functional analyses and RNA expression analyses suggest that the chromosome 6 locus is an eQTL for KIF25. Polygenic risk scores derived using the COGA SRE-T and SRE-5 GWAS predicted 0.47% to 2.48% of variances in AD and DSM-IV AD criterion count in independent datasets. This study highlights the genetic contribution of alcohol response phenotypes to the etiology of alcohol use disorders.

Predictors of Increases in Alcohol Problems and Alcohol Use Disorders in Offspring in the San Diego Prospective Study

BACKGROUND

The 35-year-long San Diego Prospective Study documented 2-fold increases in alcohol problems and alcohol use disorders (AUDs) in young-adult drinking offspring compared to rates in their fathers, the original probands. The current analyses use the same interviews and questionnaires at about the same age in members of the 2 generations to explore multiple potential contributors to the generational differences in adverse alcohol outcomes.

METHODS

Using data from recent offspring interviews, multiple cross-generation differences in characteristics potentially related to alcohol problems were evaluated in 3 steps: first through direct comparisons across probands and offspring at about age 30; second by backward linear regression analyses of predictors of alcohol problems within each generation; and finally third through R-based bootstrapped linear regressions of differences in alcohol problems in randomly matched probands and offspring.

RESULTS

The analyses across the analytical approaches revealed 3 consistent predictors of higher alcohol problems in the second generation. These included the following: (i) a more robust relationship to alcohol problems for offspring with a low level of response to alcohol; (ii) higher offspring values for alcohol expectancies; and (iii) higher offspring impulsivity.

CONCLUSIONS

The availability of data across generations offered a unique perspective for studying characteristics that may have contributed to a general finding in the literature of substantial increases in alcohol problems and AUDs in recent generations. If replicated, these results could suggest approaches to be used by parents, healthcare workers, insurance companies, and industry in their efforts to mitigate the increasing rates of alcohol problems in younger generations.

Performance of the Self-Report of the Effects of Alcohol Questionnaire Across Sexes and Generations

BACKGROUND

Low level of responses (low LRs) to alcohol established using the Self-Report of the Effects of Alcohol (SRE) questionnaire are genetically influenced phenotypes related to heavy drinking and alcohol problems. To date, most studies using SREs focused on scores for the number of drinks needed for effects across the first 5 times of drinking (SRE-5), and few evaluated scores that also included the prior 3 months and heaviest drinking periods (SRE-T). This paper evaluates characteristics of SRE-5 and SRE-T within and across generations.

METHODS

Data were extracted from 407 participants across 2 generations of 107 families in the San Diego Prospective Study (SDPS). Pearson's product-moment correlations for SRE-5 and SRE-T were determined across first-degree relatives both within and across generations and sexes, as well as correlations of each measure to maximum drinking quantities and alcohol problems.

RESULTS

Responding to 4 hypotheses, first the analyses demonstrated significant within-generation positive correlations for both SRE measures across brother-brother and sister-sister pairs as well as cross-generation correlations for fathers and sons, although correlations for mothers and daughters were not robust. Second, both SRE-5 and SRE-T correlated with maximum drinks and alcohol problems for both sexes and both generations. Third, within parental and offspring generations SRE-T correlated more robustly than SRE-5 to maximum drinks and alcohol problems. Fourth, across generations SRE values for sons were more closely related to drinking quantities and problems than for their fathers, but the mother-daughter SRE relationships to adverse alcohol characteristics were not different.

CONCLUSIONS

Both the SRE-5 and SRE-T offered useful information about propensities toward heavier drinking and alcohol problems in SDPS families. Correlations with adverse alcohol outcomes were greater for the more broad-based SRE-T, but both scores appeared to be genetically influenced and continue to operate in a robust manner in both generations of these families.

The Genetic Relationship Between Alcohol Consumption and Aspects of Problem Drinking in an Ascertained Sample

BACKGROUND

Genomewide association studies (GWAS) have begun to identify loci related to alcohol consumption, but little is known about whether this genetic propensity overlaps with specific indices of problem drinking in ascertained samples.

METHODS

In 6,731 European Americans who had been exposed to alcohol, we examined whether polygenic risk scores (PRS) from a GWAS of weekly alcohol consumption in the UK Biobank predicted variance in 6 alcohol-related phenotypes: alcohol use, maximum drinks within 24 hours (MAXD), total score on the Self-Rating of the Effects of Ethanol Questionnaire (SRE-T), DSM-IV alcohol dependence (DSM4AD), DSM-5 alcohol use disorder symptom counts (DSM5AUDSX), and reduction/cessation of problematic drinking. We also examined the extent to which an single nucleotide polymorphism (rs1229984) in ADH1B, which is strongly associated with both alcohol consumption and dependence, contributed to the polygenic association with these phenotypes and whether PRS interacted with sex, age, or family history of alcoholism to predict alcohol-related outcomes. We performed mixed-effect regression analyses, with family membership and recruitment site included as random effects, as well as survival modeling of age of onset of DSM4AD.

RESULTS

PRS for alcohol consumption significantly predicted variance in 5 of the 6 outcomes: alcohol use (Δmarginal R2  = 1.39%, Δ area under the curve [AUC] = 0.011), DSM4AD (Δmarginal R2  = 0.56%; ΔAUC = 0.003), DSM5AUDSX (Δmarginal R2  = 0.49%), MAXD (Δmarginal R2  = 0.31%), and SRE-T (Δmarginal R2  = 0.22%). PRS were also associated with onset of DSM4AD (hazard ratio = 1.11, p = 2.08e-5). The inclusion of rs1229984 attenuated the effects of the alcohol consumption PRS, particularly for DSM4AD and DSM5AUDSX, but the PRS continued to exert an independent effect for all 5 alcohol measures (Δmarginal R2 after controlling for ADH1B = 0.14 to 1.22%). Interactions between PRS and sex, age, or family history were nonsignificant.

CONCLUSIONS

Genetic propensity for typical alcohol consumption was associated with alcohol use and was also associated with 4 of the additional 5 outcomes, though the variance explained in this sample was modest. Future GWAS that focus on the multifaceted nature of AUD, which goes beyond consumption, might reveal additional information regarding the polygenic underpinnings of problem drinking.

The Relationship Between Regional Cerebral Blood Flow Estimates and Alcohol Problems at 5-Year Follow-Up: The Role of Level of Response

BACKGROUND

Acute alcohol consumption is associated with temporarily increased regional cerebral blood flow (CBF). The extent of this increase appears to be moderated by individual differences in the level of response (LR) to alcohol's subjective effects. The low LR phenotype is a known risk factor for the development of alcohol problems. This study investigates how the low LR phenotype relates to the relationship between alcohol-related changes in CBF and alcohol problems 5 years later.

METHODS

Young adults (ages 18 to 25) were selected based on their LR to alcohol and underwent a neuroimaging protocol including arterial spin labeling and functional scans. These participants were recontacted ~5 years later and assessed on alcohol outcomes. A final sample of 107 subjects (54 low and 53 high LR subjects) was included in the analyses. Whole-brain analysis revealed 5 clusters of significant alcohol-induced, versus placebo-induced, CBF changes that were consistent with a previous report. Peak alcohol-placebo CBF response was extracted from these regions and, along with the LR group, submitted to a hierarchical linear regression predicting alcohol problems. Analyses controlled for age, sex, and baseline alcohol problems.

RESULTS

In the regression analysis, greater alcohol-placebo CBF difference in the right middle/superior/inferior frontal gyri and bilateral anterior cingulate gyri clusters predicted greater future alcohol problems for the low LR group, whereas this relationship was not found to be significant in the high LR group.

CONCLUSIONS

This study demonstrates a clinically important relationship between CBF and future alcohol problems, particularly in individuals with a low LR phenotype. These initial results help to elucidate the neurobiological pathways involved in the development of alcohol use disorders for individuals with low LR.

Meta-Analysis of Genetic Influences on Initial Alcohol Sensitivity

BACKGROUND

Previous studies indicate that low initial sensitivity to alcohol may be a risk factor for later alcohol misuse. Evidence suggests that initial sensitivity is influenced by genetic factors, but few molecular genetic studies have been reported.

METHODS

We conducted a meta-analysis of 2 population-based genome-wide association studies of the Self-Rating of the Effects of Alcohol scale. Our final sample consisted of 7,339 individuals (82.3% of European descent; 59.2% female) who reported having used alcohol at least 5 times. In addition, we estimated single nucleotide polymorphism (SNP)-based heritability and conducted a series of secondary aggregate genetic analyses.

RESULTS

No individual locus reached genome-wide significance. Gene and set based analyses, both overall and using tissue-specific expression data, yielded largely null results, and genes previously implicated in alcohol problems and consumption were overall not associated with initial sensitivity. Only 1 gene set, related to hormone signaling and including core clock genes, survived correction for multiple testing. A meta-analysis of SNP-based heritability resulted in a modest estimate of h SNP 2  = 0.19 (SE = 0.10), though this was driven by 1 sample (N = 3,683, h SNP 2  = 0.36, SE = 0.14, p = 0.04). No significant genetic correlations with other relevant outcomes were observed.

CONCLUSIONS

Findings yielded only modest support for a genetic component underlying initial alcohol sensitivity. Results suggest that its biological underpinnings may diverge somewhat from that of other alcohol outcomes and may be related to core clock genes or other aspects of hormone signaling. Larger samples, ideally of prospectively assessed samples, are likely necessary to improve gene identification efforts and confirm the current findings.

A 22-Year Follow-Up (Range 16 to 23) of Original Subjects with Baseline Alcohol Use Disorders from the Collaborative Study on Genetics of Alcoholism

BACKGROUND

Recent reports indicate higher-than-expected problematic drinking in older populations. However, few data describe how to predict which older individuals are most likely to demonstrate alcohol-related problems, including those with earlier alcohol use disorders (AUDs). These analyses evaluate predictors of alcohol outcomes in individuals with earlier AUDs in the Collaborative Study on Genetics of Alcoholism (COGA).

METHODS

Original COGA participants with baseline AUDs at about age 40 were interviewed 13 to 26 years later and placed into clinically derived outcome categories. Chi-square and analysis of variance evaluated baseline differences across 4 outcome groups, with significant items entered into binary logistic regression backwards elimination analyses predicting outcomes.

RESULTS

Low-Risk Drinkers (N = 100) at follow-up were predicted by baseline higher levels of response to alcohol (high LRs), lower histories of alcohol treatment, experience with fewer types of illicit drugs, and were more likely to have been widowed. At follow-up, Problem Drinkers (N = 192) differed from High-Risk Drinkers (N = 93) who denied multiple alcohol problems by exhibiting baseline lower LRs, higher Sensation Seeking, and a higher proportion who were widowed. Abstinent (N = 278) outcomes were predicted by a history of higher baseline AUD treatments, higher alcohol problems, lower usual drinks, as well as older age and European American heritage. Thirty-four subjects (4.9%) could not be classified and were not included in these analyses.

CONCLUSIONS

These results generated from AUD individuals from both treatment and nontreatment settings reinforce low probabilities of recent Low-Risk Drinking in individuals with AUDs, but also suggest many individuals with AUDs demonstrate good outcomes 2 decades later.

A Critical Review of Methods and Results in the Search for Genetic Contributors to Alcohol Sensitivity

Attributes of alcohol sensitivity are present before alcohol use disorders (AUDs) develop, they predict those adverse alcohol outcomes, are familial in nature, and many are heritable. Whether measured by alcohol challenges or retrospective reports of numbers of drinks required for effects, alcohol sensitivity reflects multiple phenotypes, including low levels of alcohol response and alcohol-related stimulation. Identification of genes that contribute to alcohol sensitivity could help identify individuals carrying risks for AUDs through their alcohol responses for whom early intervention might mitigate their vulnerability. Such genes could also improve understanding of biological underpinnings of AUDs, which could lead to new treatment approaches. However, the existing literature points to a wide range of genetic mechanisms that might contribute to alcohol responses, and few such genetic findings have been widely replicated. This critical review describes the potential impact of the diverse methods used to study sensitivity on the diversity of genetic findings that have been reported, places the genetic variants mentioned in the literature into broader categories rather than isolated results, and offers suggestions regarding how to advance the field by interpreting findings in light of the methods used to select research subjects and to measure alcohol sensitivity. To date, the most promising results have been for GABA, glutamate, opioid, dopamine, serotonin, and cholinergic system genes. The more gene variants that can be identified as contributors to sensitivity the better future gene screening platforms or polygenic scores are likely to be.

Adolescent brain cognitive development (ABCD) study: Overview of substance use assessment methods

One of the objectives of the Adolescent Brain Cognitive Development (ABCD) Study (https://abcdstudy.org/) is to establish a national longitudinal cohort of 9 and 10 year olds that will be followed for 10 years in order to prospectively study the risk and protective factors influencing substance use and its consequences, examine the impact of substance use on neurocognitive, health and psychosocial outcomes, and to understand the relationship between substance use and psychopathology. This article provides an overview of the ABCD Study Substance Use Workgroup, provides the goals for the workgroup, rationale for the substance use battery, and includes details on the substance use module methods and measurement tools used during baseline, 6-month and 1-year follow-up assessment time-points. Prospective, longitudinal assessment of these substance use domains over a period of ten years in a nationwide sample of youth presents an unprecedented opportunity to further understand the timing and interactive relationships between substance use and neurocognitive, health, and psychopathology outcomes in youth living in the United States.

The Cerebellar GABAAR System as a Potential Target for Treating Alcohol Use Disorder

In the brain, fast inhibitory neurotransmission is mediated primarily by the ionotropic subtype of the gamma-aminobutyric acid (GABA) receptor subtype A (GABA_AR). It is well established that the brain's GABA_AR system mediates many aspects of neurobehavioral responses to alcohol (ethanol; EtOH). Accordingly, in both preclinical studies and some clinical scenarios, pharmacologically targeting the GABA_AR system can alter neurobehavioral responses to acute and chronic EtOH consumption. However, many of the well-established interactions of EtOH and the GABA_AR system have been identified at concentrations of EtOH ([EtOH]) that would only occur during abusive consumption of EtOH (≥40 mM), and there are still inadequate treatment options for prevention of or recovery from alcohol use disorder (AUD, including abuse and dependence). Accordingly, there is a general acknowledgement that more research is needed to identify and characterize: (1) neurobehavioral targets of lower [EtOH] and (2) associated brain structures that would involve such targets in a manner that may influence the development and maintenance of AUDs.Nearly 15 years ago it was discovered that the GABA_AR system of the cerebellum is highly sensitive to EtOH, responding to concentrations as low as 10 mM (as would occur in the blood of a typical adult human after consuming 1-2 standard units of EtOH). This high sensitivity to EtOH, which likely mediates the well-known motor impairing effects of EtOH, combined with recent advances in our understanding of the role of the cerebellum in non-motor, cognitive/emotive/reward processes has renewed interest in this system in the specific context of AUD. In this chapter we will describe recent advances in our understanding of cerebellar processing, actions of EtOH on the cerebellar GABA_AR system, and the potential relationship of such actions to the development of AUD. We will finish with speculation about how cerebellar specific GABA_AR ligands might be effective pharmacological agents for treating aspects of AUD.

Mediation of effects of the level of response to alcohol and impulsivity 15 years later in 36-year-old men: Implications for prevention efforts

BACKGROUND

Although the prevalence of alcohol use disorders (AUDs) has increased in older individuals in the recent decade, there are few programs to mitigate that increase. The current analyses evaluate the feasibility of applying to older drinkers elements of an approach to prevent heavier drinking in young adults by focusing on mediators of effects of two risk factors for alcohol problems, low levels of response to alcohol (low LRs) and higher impulsivity.

METHODS

Data were extracted from the San Diego Prospective Study (SDPS). Structural Equation Models evaluated relationships among age 36 low LRs and higher impulsivity; age 46 perceived peer drinking, alcohol expectancies, and drinking to cope; and age 51 alcohol problems, even after controlling for age 36 alcohol problems.

RESULTS

Relationships of age 36 low LRs to later alcohol problems was both direct and linked to age 46 heavy drinking peers. LR also operated indirectly through peer drinking to alcohol expectancies and drinking to cope. Age 36 impulsivity had no direct path to later alcohol problems and operated primarily through mediation by alcohol expectancies and via expectancies to drinking to cope. After controlling for age 36 alcohol problems, the low LR and impulsivity results remained robust.

CONCLUSIONS

Programs for mitigating increases in alcohol problems in middle-age drinkers should consider identifying individuals with low LRs and/or higher impulsivity and implementing prevention approaches similar to a program used in young adults. The approach should emphasize some different mediators for older drinkers with low LRs and those with higher impulsivity.

A Review of Developmental Considerations in Human Laboratory Alcohol Research

PURPOSE OF REVIEW

Human laboratory studies involving alcohol administration have generated critical knowledge about individual differences in risk for alcohol use disorder (AUD), but have primarily involved adult populations and cross-sectional research designs. Ethical constraints have largely precluded human laboratory alcohol research in adolescence, and prospective studies have been rare. This paper provides an overview of developmental considerations in human laboratory alcohol research, with a focus on studies conducted with youth.

RECENT FINDINGS

Recent human laboratory studies from Europe and Canada have examined aspects of alcohol response during late adolescence, while recent survey studies from the United States have highlighted methods for circumventing alcohol administration in studies of adolescents.

SUMMARY

Across several decades of research, exceedingly few laboratory studies have examined developmental differences in alcohol responses or utilized prospective designs. Efforts to prioritize prospective research would further clarify the role of alcohol sensitivity traits as predictors or markers of AUD onset and progression.

Women's Alcohol Sensitivity Predicts Alcohol-Related Regretted Sex

BACKGROUND

Low sensitivity (LS) to alcohol's acute effects is a known risk factor for heavy drinking and its negative consequences. However, LS could be protective due to LS drinkers being less impaired at a given level of consumption. Here, we tested whether LS is associated with differences in men's and women's reports of alcohol-related regretted sex.

METHODS

Eight hundred and one young adults (393 women) aged 21 to 35 (M = 23.11 years) recruited for a study of alcohol's effects on cognition completed self-report measures of alcohol sensitivity, typical alcohol use, and alcohol consequences (including regretted sex).

RESULTS

Participants whose alcohol sensitivity scores classified them as LS were more likely to experience alcohol-related regretted sex than were high-sensitivity (HS) participants. However, when controlling for typical alcohol use and experience of alcohol consequences in general, alcohol sensitivity was negatively associated with risk of alcohol-related regretted sex, but only among women.

CONCLUSIONS

At a given level of consumption, and controlling for experience of alcohol consequences other than regretted sex, reduced sensitivity to certain effects of alcohol may be a protective factor for women against risk for alcohol-related regretted sexual situations. This study provides insight on the unique risks of drinking among LS and HS women.

A Prospective Comparison of How the Level of Response to Alcohol and Impulsivity Relate to Future DSM-IV Alcohol Problems in the COGA Youth Panel

BACKGROUND

Alcohol problems reflect both environmental and genetic characteristics that often operate through endophenotypes like low levels of response (low LRs) to alcohol and higher impulsivity. Relationships of these preexisting characteristics to alcohol problems have been studied, but few analyses have included both low LR and impulsivity in the same model.

METHODS

We extracted prospective data from 1,028 participants in the Prospective Youth Sample of the Collaborative Study on the Genetics of Alcoholism (COGA). At Time 1 (age 18), these drinking but non-alcohol-dependent males and females completed the Barratt Impulsivity Scale and the Self-Report of the Effects of Alcohol questionnaire regarding drinks required for effects the first 5 times of drinking (SRE5-LR). Two years later, they reported perceived drinking patterns of peers (PEER), their own alcohol expectancies (EXPECT), and their drinking to cope with stress (COPE). Subsequently, at Time 3, participants reported numbers of up to 11 DSM-IV alcohol criterion items experienced in the 2 years since Time 2 (ALC PROBS). Data were analyzed using structural equation modeling (SEM).

RESULTS

In the SEM, Baseline SRE5-LR and impulsivity were weakly related and did not interact in predicting later ALC PROBS. LR was directly linked to Time 3 ALC PROBS and to PEER, but had no direct path to EXPECT, with partial mediation to ALC PROBS through PEER to EXPECT and via COPE. Impulsivity did not relate directly to ALC PROBS or PEER, but was directly related to EXPECT and COPE, with effects on ALC PROBS also operating through EXPECT and COPE.

CONCLUSIONS

Low LRs and impulsivity related to Time 3 ALC PROBS through somewhat different paths. Education- and counseling-based approaches to mitigate future alcohol problems may benefit from emphasizing different potential mediators of adverse alcohol outcomes for youth with low LRs versus those with high impulsivity or both characteristics.

The Ability of Functional Magnetic Resonance Imaging to Predict Heavy Drinking and Alcohol Problems 5 Years Later

BACKGROUND

Low levels of alcohol responses (low LRs) are genetically influenced phenotypes that are identified before alcohol dependence and predict future heavy drinking and alcohol problems. A recent paper described 13 LR-related blood oxygen level-dependent (BOLD) response contrast patterns observed during an emotional face recognition task that might reflect cognitive processes contributing to LR and that might themselves predict adverse alcohol outcomes (Paulus et al., Biol Psychiatry 2012; 72: 848). This paper evaluates the predictive implications of those functional magnetic resonance imaging (fMRI) patterns.

METHODS

Of 120 subjects from Paulus and colleagues (2012), 114 (57 low and high LRs; ~50% females) were interviewed 5 years later at age 25. Correlations between baseline fMRI patterns and alcohol-related outcomes were evaluated, and regression analyses were used to determine if BOLD response contrasts incremented over LR in predicting outcomes.

RESULTS

Baseline fMRI patterns in 5 of 13 baseline regions of interest correlated with adverse outcomes. Such patterns in insular regions, particularly the left anterior insula, and the right frontal gyrus, added to LR in predicting alcohol problems. The relationships remained robust when exact binomial procedures were used, but, reflecting the small sample size, it was not possible to adequately consider Bonferroni corrections.

CONCLUSIONS

The data suggest that fMRI BOLD response contrasts predicted heavier drinking and alcohol problems 5 years later, even after considering baseline low LRs. Future work will focus on whether fMRI results can predict outcomes in larger samples and among young nondrinkers, as well as how the imaging results increase understanding of the processes through which LR operates.

A prospective longitudinal model predicting early adult alcohol problems: evidence for a robust externalizing pathway

BACKGROUND

Risk factors for alcohol problems (AP) include biological and environmental factors that are relevant across development. The pathways through which these factors are related, and how they lead to AP, are optimally considered in the context of a comprehensive developmental model.

METHOD

Using data from a prospectively assessed, population-based UK cohort, we constructed a structural equation model that integrated risk factors reflecting individual, family and peer/community-level constructs across childhood, adolescence and young adulthood. These variables were used to predict AP at the age of 20 years.

RESULTS

The final model explained over 30% of the variance in liability to age 20 years AP. Most prominent in the model was an externalizing pathway to AP, with conduct problems, sensation seeking, AP at age 17.5 years and illicit substance use acting as robust predictors. In conjunction with these individual-level risk factors, familial AP, peer relationships and low parental monitoring also predicted AP. Internalizing problems were less consistently associated with AP. Some risk factors previously identified were not associated with AP in the context of this comprehensive model.

CONCLUSIONS

The etiology of young adult AP is complex, influenced by risk factors that manifest across development. The most prominent pathway to AP is via externalizing and related behaviors. These findings underscore the importance of jointly assessing both biologically influenced and environmental risk factors for AP in a developmental context.

Prediction of Long-Term Outcomes in Young Adults with a History of Adolescent Alcohol-Related Hospitalization

AIMS

Empirical data concerning the long-term psychosocial development of adolescents admitted to inpatient treatment with alcohol intoxication (AIA) are lacking. The aim of this study was to identify the factors that, at the time of admission, predict future substance use, alcohol use disorders (AUD), mental health treatment, delinquency and life satisfaction.

METHODS

We identified 1603 cases of AIA treated between 2000 and 2007 in one of five pediatric departments in Germany. These former patients were invited to participate in a telephone interview. Medical records were retrospectively analyzed extracting potential variables predicting long-term outcomes.

RESULTS

Interviews were conducted with 277 individuals, 5-13 [mean 8.3 (SD 2.3)] years after treatment, with a response rate of 22.7%; of these, 44.8% were female. Mean age at the interview was 24.4 (SD 2.2) years. Logistic and linear regression models revealed that being male, using illicit substances and truancy or runaway behavior in adolescence predicted binge drinking, alcohol dependence, use of illicit substances and poor general life satisfaction in young adulthood, explaining between 13 and 24% of the variance for the different outcome variables.

CONCLUSIONS

This naturalistic study confirms that known risk factors for the development of AUD also apply to AIA. This finding facilitates targeted prevention efforts for those cases of AIA who need more than the standard brief intervention for aftercare.

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.

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

OBJECTIVE

A person's pattern of heavier drinking often changes over time, especially during the early drinking years, and reflects complex relationships among a wide range of characteristics. Optimal understanding of the predictors of drinking during times of change might come from studies of trajectories of alcohol intake rather than cross-sectional evaluations.

METHOD

The patterns of maximum drinks per occasion were evaluated every 2 years between the average ages of 18 and 24 years for 833 subjects from the Collaborative Study on the Genetics of Alcoholism. Latent class growth analysis identified latent classes for the trajectories of maximum drinks, and then logistic regression analyses highlighted variables that best predicted class membership.

RESULTS

Four latent classes were found, including Class 1 (69%), with about 5 maximum drinks per occasion across time; Class 2 (15%), with about 9 drinks at baseline that increased to 18 across time; Class 3 (10%), who began with a maximum of 18 drinks per occasion but decreased to 9 over time; and Class 4 (6%), with a maximum of about 22 drinks across time. The most consistent predictors of higher drinking classes were female sex, a low baseline level of response to alcohol, externalizing characteristics, prior alcohol and tobacco use, and heavier drinking peers.

CONCLUSIONS

Four trajectory classes were observed and were best predicted by a combination of items that reflected demography, substance use, level of response and externalizing phenotypes, and baseline environment and attitudes.

Curious cases: Altered dose-response relationships in addiction genetics

Dose-response relationships for most addictive substances are "inverted U"-shaped. Addictive substances produce both positive features that include reward, euphoria, anxiolysis, withdrawal-relief, and negative features that include aversion, dysphoria, anxiety and withdrawal symptoms. A simple model differentially associates ascending and descending limbs of dose-response curves with rewarding and aversive influences, respectively. However, Diagnostic and Statistical Manual (DSM) diagnoses of substance dependence fail to incorporate dose-response criteria and don't directly consider balances between euphoric and dysphoric drug effects. Classical genetic studies document substantial heritable influences on DSM substance dependence. Linkage and genome-wide association studies identify modest-sized effects at any locus. Nevertheless, clusters of SNPs within selected genes display 10(-2)>p>10(-8) associations with dependence in many independent samples. For several of these genes, evidence for cis-regulatory, level-of-expression differences supports the validity of mouse models in which levels of expression are also altered. This review documents surprising, recently defined cases in which convergent evidence from humans and mouse models supports central influences of altered dose-response relationships in mediating the impact of relevant genomic variation on addiction phenotypes. For variation at loci for the α5 nicotinic acetylcholine receptor, cadherin 13, receptor type protein tyrosine phosphatase Δ and neuronal cell adhesion molecule genes, changed dose-response relationships conferred by gene knockouts in mice are accompanied by supporting human data. These observations emphasize desirability of carefully elucidating dose-response relationships for both rewarding and aversive features of abused substances wherever possible. They motivate consideration of individual differences in dose-response relationships in addiction nosology and therapeutics.

Stability of scores and correlations with drinking behaviors over 15 years for the Self-Report of the Effects of Alcohol Questionnaire

BACKGROUND

The low level of response (LR) to alcohol is an endophenotype that predicts future heavy drinking and alcohol use disorders (AUDs). LR can be measured by laboratory-based alcohol challenges or by the retrospective Self-Report of the Effects of Alcohol (SRE) questionnaire. This paper reports the relationships among these two measures and how each related to both recent and future drinking quantities and problems across 15 years in 235 men.

METHODS

Probands from the San Diego Prospective Study (SDPS) participated in alcohol challenges to determine their LR at age 20, and subsequently at ages 35, 40, 45 and 50 filled out an SRE regarding the number of standard drinks needed for up to four effects early in life (SRE5) and across early, recent, and heaviest drinking life epochs (SRET). Changes in SRE scores across time were evaluated with ANOVAs and Pearson correlations were used to evaluate how SRE5, SRET and earlier alcohol challenge-based LRs related to prior five-year drinking histories and future alcohol involvement.

RESULTS

While SRE scores decreased 9% over the 15 years, the relationships between SRE values with prior five-year drinking parameters and with future alcohol intake and problems remained robust, and even improved with advancing age. A similar pattern was seen for correlations between SRE and alcohol challenge-based LRs 15-30 years previously.

CONCLUSIONS

Alcohol challenge and SRE-based LRs related to each other, to alcohol use patterns, and to future alcohol problems across age 35-50 in the men studied here.

Comparison across two generations of prospective models of how the low level of response to alcohol affects alcohol outcomes

OBJECTIVE

This article presents the first direct comparison of level of response (LR)-based prospective models in two generations of the same families. To accomplish this, we describe results from the first prospective evaluation of potential mediators of how an earlier low LR to alcohol relates to adverse alcohol outcomes in offspring from the San Diego Prospective Study (SDPS).

METHOD

To compare with data from probands in the SDPS, new data were gathered from 86 drinking offspring (age ~20 years) during the 25-year follow-up of these families. Consistent with the usual effect of a low LR, outcomes 5 years later for both generations focused on drinking quantities as well as alcohol problems during the follow-up. A structural equation model (SEM) was used to analyze the relationships among variables, and the models in proband and offspring generations were compared using direct observations of the model results and through invariance procedures.

RESULTS

In these drinking offspring, LR correlated with 5-year outcomes (r = .48, p < .001) and the SEM R² was .48, with good fit statistics. As predicted, the LR relationship to alcohol-related outcomes was both direct and partially mediated by heavier peer drinking, positive alcohol expectancies, and using alcohol to cope with stress. These results were similar to a previously published prospective model in SDPS probands, although path coefficients were generally higher in the younger group.

CONCLUSIONS

The LR-based model of heavier drinking operated similarly across generations, with some modest differences. These results indicate that the model may be meaningful in both younger and middle-age groups.

fMRI differences between subjects with low and high responses to alcohol during a stop signal task

BACKGROUND

A low level of response (i.e., a low LR) to alcohol is a genetically influenced phenotype that predicts later alcoholism. While the low LR reflects, at least in part, a low brain response to alcohol, the physiological underpinnings of the low LR have only recently been addressed.

METHODS

Forty-nine drinking but not yet alcoholic matched pairs of 18- to 25-year-old subjects (N = 98; 53% women) with low and high LRs as established in separate alcohol challenges were evaluated in 2 event-related functional magnetic resonance imaging (fMRI) sessions (placebo and approximately 0.7 ml/kg of alcohol) while performing a validated stop signal task. The high and low LR groups had identical blood alcohol levels during the alcohol session.

RESULTS

Significant high versus low LR group and LR group × condition effects were observed in blood oxygen level-dependent (BOLD) signal during error and inhibitory processing, despite similar LR group performance on the task. In most clusters with significant (corrected p < 0.05, clusters > 1,344 μl) LR group × alcohol/placebo condition interactions, the low LR group demonstrated relatively less, whereas the high LR group demonstrated more, error and inhibition-related activation after alcohol compared with placebo.

CONCLUSIONS

This is one of the first fMRI studies to demonstrate significant differences between healthy groups with different risks of a future life-threatening disorder. The results may suggest a brain mechanism that contributes to how a low LR might enhance the risk of future heavy drinking and alcohol dependence.

Testing a level of response to alcohol-based model of heavy drinking and alcohol problems in 1,905 17-year-olds

BACKGROUND

The low level of response (LR) to alcohol is one of several genetically influenced characteristics that increase the risk for heavy drinking and alcohol problems. Efforts to understand how LR operates through additional life influences have been carried out primarily in modest-sized U.S.-based samples with limited statistical power, raising questions about generalizability and about the importance of components with smaller effects. This study evaluates a full LR-based model of risk in a large sample of adolescents from the United Kingdom.

METHODS

Cross-sectional structural equation models were used for the approximate first half of the age 17 subjects assessed by the Avon Longitudinal Study of Parents and Children, generating data on 1,905 adolescents (mean age 17.8 years, 44.2% boys). LR was measured with the Self-Rating of the Effects of Alcohol Questionnaire, outcomes were based on drinking quantities and problems, and standardized questionnaires were used to evaluate peer substance use, alcohol expectancies, and using alcohol to cope with stress.

RESULTS

In this young and large U.K. sample, a low LR related to more adverse alcohol outcomes both directly and through partial mediation by all 3 additional key variables (peer substance use, expectancies, and coping). The models were similar in boys and girls.

CONCLUSIONS

These results confirm key elements of the hypothesized LR-based model in a large U.K. sample, supporting some generalizability beyond U.S. groups. They also indicate that with enough statistical power, multiple elements contribute to how LR relates to alcohol outcomes and reinforce the applicability of the model to both genders.

A prospective evaluation of how a low level of response to alcohol predicts later heavy drinking and alcohol problems

BACKGROUND AND OBJECTIVES

Evaluations of how a genetically influenced characteristic, such as the low level of response (a low LR) to alcohol, relates to later heavy drinking and alcohol problems usually include environmental contributors. The best way to understand how LR works in the context of these additional characteristics is to study the process prospectively, but such analyses tend to be complex and the papers are sometimes cluttered with jargon. This report attempts to offer a more straightforward description of the results from such a prospective model of how a lower LR at age 20 relates to alcohol outcomes at age 40.

METHODS

A structural equation model of LR at age ∼20, outcomes of heavy drinking and problems at age ∼40, and additional characteristics at age ∼35 were tested in 378 men from the San Diego Prospective Study.

RESULTS

The results support both direct effects of age-20 LR on age-40 heavy drinking and alcohol problems, as well as indirect effects of LR through characteristics of these men at age 35. The latter include using alcohol to cope with stress and heavier drinking among peers.

CONCLUSIONS

A low LR to alcohol is an example of how both genes and environment can contribute to the risk for adverse alcohol outcomes. The identification of mechanisms through which LR impacts on later heavy drinking and problems can be approached in cross-sectional studies, but those may not be as sensitive as longitudinal models for identifying additional potential mediators of the LR-to-outcome relationship.

Comment on the paper by Quinn and Fromme entitled subjective response to alcohol challenge: a quantitative review

BACKGROUND

This commentary discusses the recent paper by Quinn and Fromme (2011), placing their results into perspective.

RESULTS

Quinn and Fromme's meta-analysis is an important and useful synthesis of a complex literature. It is clear, well written, and well reasoned, with conclusions that are relevant to both the Low Level of Response Model and the Differentiator Model.

CONCLUSIONS

Drs. Quinn and Fromme use a thorough and thoughtful approach, and I encourage researchers to address the important questions raised by their meta-analysis.

Self-Rating of the Effects of Alcohol (SRE): Predictive utility and reliability across interview and self-report administrations

The Self-Rating of the Effects of Alcohol (SRE) is a widely used and well-established measure of the level of response to alcohol. Although the SRE has been successfully used in studies of alcoholism etiology, including genetics, studies to date have not compared the self-report and interview formats. The objectives of this study are to: (a) test the predictive utility of the subscales of the SRE in relation to alcohol problems; and (b) test the reliability of the SRE in interview versus self-report formats. A sample of college drinkers (n=446) completed the SRE in a self-report format along with the Alcohol Use Disorders Identification Test (AUDIT). A subset of participants (n=34) returned to the laboratory and completed the SRE in a face-to-face interview format. All subscales of the SRE were robust predictors of alcohol problems accounting for as much as 25% of the variance in AUDIT scores. In addition, scores obtained via self-report and interview-based SRE were highly correlated (r=.70 to .80). Results support the predictive utility of the SRE and provide initial evidence that the self-report and interview formats produce reliable results and may be combined and/or used interchangeably.

ALDH2 and ADH1B interactions in retrospective reports of low-dose reactions and initial sensitivity to alcohol in Asian American college students

BACKGROUND

A mechanistic model has been proposed for how alcohol-metabolizing gene variants protect individuals from the development of alcohol use disorders, with heightened sensitivity to alcohol being an early step (endophenotype) in this model. This study was designed to determine whether possession of 2 alcohol-metabolizing genes variations, the aldehyde dehydrogenase ALDH2*2 allele and the alcohol dehydrogenase ADH1B*2 allele, was associated with self-reported sensitivity to alcohol at low doses and at initial use.

METHODS

Asian-American college students (N=784) of Chinese and Korean descent were genotyped at the ALDH2 and ADH1B loci and assessed for lifetime alcohol symptoms following 1 or 2 drinks and level of response to alcohol during the first 5 lifetime drinking episodes.

RESULTS

Participants who had an ALDH2*2 allele were more likely to report experiencing all 6 low-dose symptoms and having heightened initial response to alcohol. An interaction was found between ALDH2*2 and ADH1B*2, with ADH1B*2 being associated with heightened self-reported sensitivity to alcohol only in individuals who also possessed 1 ALDH2*2 allele.

CONCLUSIONS

These findings suggest the effects of ADH1B*2 may be felt more strongly in Asians who already have some heightened sensitivity to alcohol from possessing 1 ALDH2*2 allele, but who are not too sensitized to alcohol from possessing 2 ALDH2*2 alleles. These results offer additional insight into the discrepant findings that have been reported in the literature for the role of ADH1B*2 in response to alcohol and the development of alcohol-related problems.

Alcohol effects on cerebral blood flow in subjects with low and high responses to alcohol

BACKGROUND

Although there are multiple indications that alcohol can alter many physiological brain functions, including cerebral blood flow (CBF), studies of the latter have generally used small- or modest-sized samples. Few investigations have yet evaluated how CBF changes after alcohol relate to subsets of subjects with elevated alcoholism risks, such as those with lower levels of response (LR) to alcohol. This study used arterial spin labeling (ASL) after alcohol administration to evaluate a large sample of healthy young men and women with low and high alcohol responses, and, thus, varying risks for alcohol use disorders (AUD).

METHODS

Healthy young adult social drinkers with low and high LR (N=88, 50% women) matched on demography and drinking histories were imaged with whole-brain resting ASL ~1 hour after ingesting ~3 drinks of ethanol and after a placebo beverage (i.e., 178 ASL sessions). The relationships of CBF changes from placebo to alcohol for subjects with low and high LR were evaluated.

RESULTS

CBF increased after alcohol when compared to placebo in 5 frontal brain regions. Despite identical blood alcohol concentrations, these increases with alcohol were less prominent in individuals who required more drinks to experience alcohol-related effects (i.e., had a lower LR to alcohol). The LR group differences remained significant after covarying for recent drinking quantities.

CONCLUSIONS

The results confirm that alcohol intake is associated with acute increases in CBF, particularly in frontal regions. Less intense CBF changes were seen in subjects with a genetically influenced characteristic, a low LR to alcohol, that relates to the future risk of heavy drinking and alcohol problems.

Acute ethanol effects on brain activation in low- and high-level responders to alcohol

BACKGROUND

A low level of response (LR) to alcohol is an important endophenotype associated with an increased risk of alcoholism. However, little is known about how neural functioning may differ between individuals with low and high LRs to alcohol. This study examined whether LR group effects on neural activity varied as a function of acute alcohol consumption.

METHODS

A total of 30 matched high- and low-LR pairs (N = 60 healthy young adults) were recruited from the University of California, San Diego, and administered a structured diagnostic interview and laboratory alcohol challenge followed by two functional magnetic resonance imaging (fMRI) sessions under placebo and alcohol conditions, in randomized order. Task performance and blood oxygen level-dependent response contrast to high relative to low working memory load in an event-related visual working memory (VWM) task were examined across 120 fMRI sessions.

RESULTS

Both LR groups performed similarly on the VWM task across conditions. A significant LR group by condition interaction effect was observed in inferior frontal and cingulate regions, such that alcohol attenuated the LR group differences found under placebo (p < 0.05). The LR group by condition effect remained even after controlling for cerebral blood flow, age, and typical drinking quantity.

CONCLUSIONS

Alcohol had differential effects on brain activation for low- and high-LR individuals within frontal and cingulate regions. These findings represent an additional step in the search for physiological correlates of a low LR and identify brain regions that may be associated with the low LR response.

Comparing structural equation models that use different measures of the level of response to alcohol

BACKGROUND

The two measures of a low level of response (LR) to alcohol, an alcohol challenge and the retrospective Self-Report of the Effects of Alcohol questionnaire (SRE), each identify individuals at high risk for heavy drinking and alcohol problems. These measures also perform similarly in identifying subjects with unique functional brain imaging characteristics. However, few data are available regarding whether alcohol challenge-based and SRE-based LRs operate similarly in structural equation models (SEMs) that search for characteristics, which help to mediate how LR impacts alcohol outcomes.

METHODS

Two hundred and ninety-four men from the San Diego Prospective Study were evaluated for their LR to alcohol using alcohol challenges at approximately age 20. At approximately age 35, the same subjects filled out the SRE regarding the number of drinks needed for effects 15 to 20 years earlier. The two different LR scores for these men were used in SEM analyses evaluating how LR relates to future heavy drinking and to drinking in peers (PEER), alcohol expectancies (EXPECT), and drinking to cope (COPE) as potential mediators of the LR to drinking pattern (ALCOUT) relationships.

RESULTS

While the 2 LR measures that were determined 15 years apart related to each other at a modest level (r = 0.17, p < 0.01), the SEM results were similar regardless of the LR source. In both alcohol challenge-based and SRE-based LR models, LR related directly to ALCOUT, with partial mediation from PEER and COPE, but not through EXPECT in these 35-year-old men.

CONCLUSIONS

Consistent with the >60% overlap in prediction of outcomes for the 2 LR measures, and with results from functional brain imaging, alcohol challenge- and SRE-based LR values operated similarly in SEM models in these men.

Initial evidence of an association between OPRM1 and adolescent alcohol misuse

BACKGROUND

Considerable research efforts have attempted to identify genes associated with alcoholism among adults, yet few studies have examined adolescents. Identifying genes associated with alcohol misuse in youth is important given that the relative contribution of genetic and environmental influences on alcoholism varies across development. The purpose of this study was to examine the association between a polymorphism of the mu-opioid receptor gene (OPRM1) and alcohol misuse in a sample of youth and to test whether heightened sensitivity to the reinforcing effects of alcohol mediated this relationship.

METHODS

Adolescents (n = 187; mean age = 15.4 years; 47.6% female) were genotyped for A118G (rs1799971), a single-nucleotide polymorphism (SNP) of the OPRM1 gene, and assessed for alcohol use disorder (AUD) diagnoses and other psychopathology. Alcohol misuse was also measured continuously to maximize detection of drinking problems in youth. Drinking motives were used to capture the extent to which youth consumed alcohol to enhance positive affect.

RESULTS

AUD groups differed significantly in terms of allelic distributions of the A118G SNP, such that 51.9% of youth with an AUD carried at least one copy of the G allele compared to 16.3% of non-AUD controls. Those who carried the G allele endorsed drinking to enhance positive affect more strongly than those who were homozygous for the A allele and drinking to enhance positive affect mediated the association between OPRM1 and alcohol-related problems.

CONCLUSIONS

These data build on findings from adult studies and provide the first evidence that a polymorphism of the OPRM1 receptor gene is associated with the development of early-onset alcohol-related problems during adolescence, in part, by heightening sensitivity to the reinforcing effects of alcohol.

First positive reactions to cannabis constitute a priority risk factor for cannabis dependence

AIM

To assess the association between first reactions to cannabis and the risk of cannabis dependence.

DESIGN

A cross-sectional population-based assessment in 2007.

SETTING

A campus in a French region (Champagne-Ardennes).

PARTICIPANTS

A total of 1472 participants aged 18-21 years who reported at least one life-time cannabis consumption, of 3056 students who were screened initially [the Susceptibility Addiction Gene Environment (SAGE) study].

MEASUREMENTS

Positive and negative effects of first cannabis consumptions, present cannabis dependence and related risk factors were assessed through questionnaires.

FINDINGS

  The effects of first cannabis consumptions were associated dose-dependently with cannabis dependence at age 18-21 years, both according to the transversal approach of the SAGE study and to the prospective cohort of the Christchurch Health and Development Study (CHDS) assessed at the age of 25 years. Participants of the SAGE study who reported five positive effects of their first cannabis consumption had odds of life-time cannabis dependence that were 28.7 (95% confidence interval: 14.6-56.5) higher than those who reported no positive effects. This association remains significant after controlling for potentially confounding factors, including individual and familial variables.

CONCLUSIONS

This study suggests an association between positive reactions to first cannabis uses and risk of life-time cannabis dependence, this variable having a central role among, and through, other risk factors.

An evaluation of the full level of response to alcohol model of heavy drinking and problems in COGA offspring

OBJECTIVE

The low level of response (LR) to alcohol is an endophenotype related to heavier drinking and alcohol problems. Structural equation models (SEMs) indicate LR affects alcohol outcomes (ALCOUT) both directly and through mediation by drinking in peers (PEER), alcohol expectancies (EXPECT), and drinking to cope with stress (COPE), with some variation depending on the sample tested. This article presents the first full test of this LR-based model in young subjects from the Collaborative Study on the Genetics of Alcoholism (COGA).

METHOD

Data were generated from 325 12- to 22-year-old (47.4% male) drinking offspring from COGA families, using the Self-Report of the Effects of Alcohol questionnaire to determine LR early in the drinking career and a validated, structured interview for demography and alcohol use/problem patterns. Standardized questionnaires were used to measure PEER, EXPECT, and COPE, with the model tested through the maximum likelihood estimation for analyses of the variance/covariance matrix using both Amos and Mplus.

RESULTS

The SEM yielded good fit characteristics and explained 59% of the variance, with LR relating both directly to ALCOUT and as partially mediated by PEER and COPE. Although GENDER related to both LR and ALCOUT in the model, and AGE related to ALCOUT, the SEM results were invariant across both AGE and GENDER, with generally similar invariant results regarding the presence or absence of an alcohol-use disorder diagnosis.

CONCLUSIONS

The results support the applicability of the LR-based model of heavy drinking and alcohol problems in the COGA offspring, a group with different demography compared with the two other samples of adolescents tested to date. The modest differences observed across samples will be evaluated in future research to enhance understanding of how the model operates across socioeconomic groups.

The relationships of the level of response to alcohol and additional characteristics to alcohol use disorders across adulthood: a discrete-time survival analysis

BACKGROUND

A low level of response (LR) to alcohol has been shown to relate to a higher risk for alcohol use disorders (AUDs). However, no previous research has examined the association between LR and the development of AUDs in the context of additional robust risk factors for AUDs. This study evaluated whether LR and other related characteristics predicted the occurrence of AUDs across adulthood using discrete-time survival analysis (DTSA).

METHODS

A total of 297 probands from the San Diego Prospective Study reported on the LR to alcohol, a family history (FH) of AUDs, the typical drinking quantity, the age of drinking onset, the body mass index and the age at the baseline (T1) assessment. Alcohol use disorders (AUDs) were evaluated at the 10-year (T10), T15, T20, and T25 follow-ups.

RESULTS

A low LR to alcohol predicted AUD occurrence over the course of adulthood even after controlling for the effects of other robust risk factors. Interaction effects revealed that the impact of FH on AUDs was only observed for subjects with high T1 drinking levels, and probands with high T1 drinking were at high risk for AUDs regardless of their age of onset.

CONCLUSIONS

The findings illustrate that LR is a unique risk factor for AUDs across adulthood, and not simply a reflection of a broader range of risk factors. The continued investigation of how LR is related to AUD onset later in life will help inform treatment providers about this high-risk population, and future longitudinal evaluations will utilize DTSA to assess rates of AUD remission as well as the onset of drinking outcomes in adolescent samples.

The overlap in predicting alcohol outcome for two measures of the level of response to alcohol

BACKGROUND

Two different measures have been used to establish a person's level of response (LR) to alcohol as a risk factor for alcohol use disorders. LR values established by the alcohol challenge protocol and the Self-Report of the Effects of Ethanol (SRE) questionnaire usually correlate at 0.3 to 0.4, up to 0.6. However, it is not clear how this correlation relates to the ability of each measure to predict alcohol outcomes. This paper evaluates that overlap.

METHODS

Sixty-six Caucasian males (mean age = 22 years) from 2 protocols participated in alcohol challenges with 0.75 ml/kg of ethanol, filled out the SRE, and were followed with a structured interview approximately 5 years later. The relationship between the subjective feelings of intoxication at the time of peak breath alcohol levels from the alcohol challenge and the SRE score for a time early in the drinking career were evaluated regarding predicting the drinks per occasion in the 6 months prior to follow-up.

RESULTS

Cross-sectional correlations between alcohol challenge and SRE LR's ranged from -0.25 (p < 0.05) to -0.32 (p = 0.02) for the full sample, and the 2 LR measures correlated with drinking at follow-up (-0.26 and 0.41, respectively). The SRE measure was more robust than the challenge in a regression analysis predicting the outcome in the context of other baseline predictors (e.g., drinking at baseline). As much as 60% of the ability of the more well established (gold standard) alcohol challenge LR to predict outcome was shared with the SRE. The alcohol challenge accounted for as much as 44% of the ability of the SRE to predict outcome.

CONCLUSIONS

The SRE-generated LR overlapped considerably with the alcohol challenge LR in the ability to predict future heavier drinking.