Childhood adversity moderates the effect of ADH1B on risk for alcohol-related phenotypes in Jewish Israeli drinkers

Serial mediating effects of childhood trauma and conduct behaviors on the impact of family history among patients with alcohol use disorder

Family history (FH) of alcoholism increases the risk of alcohol use disorder (AUD); however, the contribution of childhood trauma (CT) in this respect remains unclear. This study investigated the relationship between FH and AUD-related clinical characteristics (social onset, antisocial tendency, and severity of problematic alcohol consumption) through the mediating effects of childhood trauma (CT) and conduct behaviors (CB) in a Korean male population with AUD. A total of 304 patients hospitalized for AUD at 16 psychiatric hospitals completed standardized questionnaires, including self-rated scales. Mediation analyses were performed using the SPSS macro PROCESS. Individuals with positive FH (133, 44%) had greater CT and CB and more severe AUD-related clinical characteristics than those without FH (171, 56%). In the present serial mediation model, FH had significant direct and indirect effects on AUD-related clinical characteristics through CT and CB. Indirect effects were 21.3% for social onset, 46.3%, antisocial tendency, and 37.9% for problematic drinking. FH directly contributed to AUD-related clinical characteristics, and CT and CB played mediating roles. This highlights the importance of careful intervention and surveillance of adverse childhood experiences and conduct disorder to prevent and mitigate alcohol-related problems in individuals with FH of AUD.

Early parent-child interactions and substance use disorder: An attachment perspective on a biopsychosocial entanglement

This review aims to elucidate environmental and genetic factors, as well as their epigenetic and neuroendocrine moderators, that may underlie the association between early childhood experiences and Substance Use Disorders (SUD), through the lens of parental attachment. Here we review those attachment-related studies that examined the monoaminergic systems, the hypothalamic pituitary adrenal stress response system, the oxytoninergic system, and the endogenous opioid system from a genetic, epigenetic, and neuroendocrine perspective. Overall, the selected studies point to a moderating effect of insecure attachment between genetic vulnerability and SUD, reasonably through epigenetic modifications. Preliminary evidence suggests that vulnerability to SUDs is related with hypo-methylation (e.g. hyper-expression) of high-risk polymorphisms on the monoaminergic and hypothalamic pituitary adrenal system and hyper-methylation (e.g. hypo-expressions) of protective polymorphisms on the opioid and oxytocin system. These epigenetic modifications may induce a cascade of neuroendocrine changes contributing to the subclinical and behavioural manifestations that precede the clinical onset of SUD. Protective and supportive parenting could hence represent a key therapeutic target to prevent addiction and moderate insecure attachment.

Quantile-Specific Heritability of Intakes of Alcohol but not Other Macronutrients

Genetic heritability (h²) of alcohol use is reported to be greater in rural dwellers, distressed marriages, low socioeconomic status, in girls who are unmarried or lacking closeness with their parents or religious upbringing, in less-educated men, and in adolescents with peers using alcohol. However, these are all risk factors for heavy drinking, and the greater heritability could be due to quantile-dependent expressivity, i.e., h² dependent upon whether the phenotype (alcohol intake) is high or low relative to its distribution. Quantile regression showed that h² estimated from the offspring-parent regression slope increased significantly from lowest to highest gram/day of alcohol consumption (0.006 ± 0.001 per percent, P = 1.1 × 10^-7). Heritability at the 90th percentile of the sample distribution (0.557 ± 0.116) was 4.5-fold greater than at the 10th percentile (0.122 ± 0.037). Heritabilities for intakes of other macronutrients were not quantile-dependent. Thus quantile-dependent expressivity may explain the higher estimated heritability associated with risk factors for high alcohol consumption.

Psychosocial moderation of polygenic risk for cannabis involvement: the role of trauma exposure and frequency of religious service attendance

Cannabis use and disorders (CUD) are influenced by multiple genetic variants of small effect and by the psychosocial environment. However, this information has not been effectively incorporated into studies of gene-environment interaction (GxE). Polygenic risk scores (PRS) that aggregate the effects of genetic variants can aid in identifying the links between genetic risk and psychosocial factors. Using data from the Pasman et al. GWAS of cannabis use (meta-analysis of data from the International Cannabis Consortium and UK Biobank), we constructed PRS in the Collaborative Study on the Genetics of Alcoholism (COGA) participants of European (N: 7591) and African (N: 3359) ancestry. The primary analyses included only individuals of European ancestry, reflecting the ancestral composition of the discovery GWAS from which the PRS was derived. Secondary analyses included the African ancestry sample. Associations of PRS with cannabis use and DSM-5 CUD symptom count (CUDsx) and interactions with trauma exposure and frequency of religious service attendance were examined. Models were adjusted for sex, birth cohort, genotype array, and ancestry. Robustness models were adjusted for cross-term interactions. Higher PRS were associated with a greater likelihood of cannabis use and with CUDsx among participants of European ancestry (p < 0.05 and p < 0.1 thresholds, respectively). PRS only influenced cannabis use among those exposed to trauma (R2: 0.011 among the trauma exposed vs. R2: 0.002 in unexposed). PRS less consistently influenced cannabis use among those who attend religious services less frequently; PRS × religious service attendance effects were attenuated when cross-term interactions with ancestry and sex were included in the model. Polygenic liability to cannabis use was related to cannabis use and, less robustly, progression to symptoms of CUD. This study provides the first evidence of PRS × trauma for cannabis use and demonstrates that ignoring important aspects of the psychosocial environment may mask genetic influences on polygenic traits.

Genetics of Alcoholism

PURPOSE OF REVIEW

We review the search for genetic variants that affect the risk for alcohol dependence and alcohol consumption.

RECENT FINDINGS

Variations in genes affecting alcohol metabolism (ADH1B, ALDH2) are protective against both alcohol dependence and excessive consumption, but different variants are found in different populations. There are different patterns of risk variants for alcohol dependence vs. consumption. Variants for alcohol dependence, but not consumption, are associated with risk for other psychiatric illnesses. ADH1B and ALDH2 strongly affect both consumption and dependence. Variations in many other genes affect both consumption and dependence-or one or the other of these traits-but individual effect sizes are small. Evidence for other specific genes that affect dependence is not yet strong. Most current knowledge derives from studies of European-ancestry populations, and large studies of carefully phenotyped subjects from different populations are needed to understand the genetic contributions to alcohol consumption and alcohol use disorders.

Alcohol Dehydrogenases, Aldehyde Dehydrogenases, and Alcohol Use Disorders: A Critical Review

Alcohol use disorders (AUDs) are complex traits, meaning that variations in many genes contribute to the risk, as does the environment. Although the total genetic contribution to risk is substantial, most individual variations make only very small contributions. By far the strongest contributors are functional variations in 2 genes involved in alcohol (ethanol [EtOH]) metabolism. A functional variant in alcohol dehydrogenase 1B (ADH1B) is protective in people of European and Asian descent, and a different functional variant in the same gene is protective in those of African descent. A strongly protective variant in aldehyde dehydrogenase 2 (ALDH2) is essentially only found in Asians. This highlights the need to study a wide range of populations. The likely mechanism of protection against heavy drinking and AUDs in both cases is alteration in the rate of metabolism of EtOH that at least transiently elevates acetaldehyde. Other ADH and ALDH variants, including functional variations in ADH1C, have also been implicated in affecting drinking behavior and risk for alcoholism. The pattern of linkage disequilibrium in the ADH region and the differences among populations complicate analyses, particularly of regulatory variants. This critical review focuses upon the ADH and ALDH genes as they affect AUDs.

The possible mediating effect of alcohol dependence on the relationship between adverse childhood experiences and attempted suicide

Adverse childhood experiences (ACEs) and alcohol dependence (AD) carry independent risks for suicidal behavior. While the strength of the association between ACEs and attempted suicide is weakened following adjustment for AD, no study to date has directly been performed to determine whether AD affects the risk of suicide attributable to ACEs. The study aimed to examine the possible role of alcohol dependence (AD) in the relationship between various ACEs and attempted suicide. This cross-sectional study assessed history of ACEs among 184 AD patients and 205 control participants using the Family Health Questionnaire. Lifetime history of attempted suicide was collected using the Chinese version of the Composite International Diagnostic Interview. We used the Sobel test to examine the mediating effects of AD on the relationship between ACEs and attempted suicide. Results showed that the suicide attempters were associated with higher rates of AD and ACEs. The regression analysis showed that AD and multiple ACEs exposure are independently associated with attempted suicide. AD appears as a partial mediator in the relationship between attempted suicide and the specific type of ACE (exposure to a battered mother or sexual abuse) or exposure to ≥3 types of ACEs. We conclude that AD might partially mediate the associations detected between attempted suicide and exposure to a battered mother, sexual abuse, and ≥3 types of ACEs. These observations may provide important insight for intervention strategies aimed at reducing the risk of suicide attempts.

ADH1B: From alcoholism, natural selection, and cancer to the human phenome

The ADH1B (Alcohol Dehydrogenase 1B (class I), Beta Polypeptide) gene and its best-known functional alleles, Arg48His (rs1229984, ADH1B*2) and Arg370Cys (rs2066702, ADH1B*3), have been investigated in relation to many phenotypic traits; most frequently including alcohol metabolism and alcohol drinking behaviors, but also human evolution, liver function, cancer, and, recently, the comprehensive human phenome. To understand ADH1B functions and consequences, we provide here a bioinformatic analysis of its gene regulation and molecular functions, literature review of studies focused on this gene, and a discussion regarding future research perspectives. Certain ADH1B alleles have large effects on alcohol metabolism, and this relationship particularly encourages further investigations in relation to alcoholism and alcohol-associated cancer to understand better the mechanisms by which alcohol metabolism contributes to alcohol abuse and carcinogenesis. We also observed that ADH1B has complex mechanisms that regulate its expression across multiple human tissues, and these may be involved in cardiac and metabolic traits. Evolutionary data strongly suggest that the selection signatures at the ADH1B locus are primarily related to effects other than those on alcohol metabolism. This is also supported by the involvement of ADH1B in multiple molecular pathways and by the findings of our recent phenome-wide association study. Accordingly, future studies should also investigate other functions of ADH1B potentially relevant for the human phenome. © 2017 Wiley Periodicals, Inc.

Interaction between ADH1B*3 and alcohol-facilitating social environments in alcohol behaviors among college students of african descent

BACKGROUND AND OBJECTIVES

Although alcohol-facilitating social environmental factors, such as alcohol offers and high perceived peer drinking norms, have been extensively studied as determinants of college drinking, their role among college students of African descent remains understudied. Furthermore, gene-environment interaction research suggests that the effects of alcohol-facilitating environments may differ as a function of genetic factors. Specifically, the alcohol dehydrogenase gene's ADH1B*3 allele, found almost exclusively in persons of African descent, may modulate the association of risky social environments with alcohol behaviors. The current study examined whether the ADH1B*3 allele attenuated the relationship between alcohol-facilitating environments (ie, alcohol offers and perceived peer drinking norms) and alcohol behaviors.

METHOD

Participants were 241 undergraduate students who self-identified as being of African descent (mean age = 20 years [SD = 4.11]; 66% female).

RESULTS

Significant interaction effects of ADH1B*3 with alcohol offers were found on alcohol use frequency (incidence rate ratio [IRR] = 1.14) and on drinking consequences (IRR = 1.21). ADH1B*3 also interacted with perceived peer norms on drinking consequences (IRR = 1.41). Carriers of the ADH1B*3 allele drank less frequently and experienced fewer negative consequences than non-carriers when exposed to lower levels of alcohol offers and perceived peer drinking. In contrast, in high alcohol-facilitating environments, no protective genetic effect was observed.

DISCUSSION AND CONCLUSION

This study demonstrates that ADH1B*3 may protect college students of African descent against alcohol outcomes, although only in low alcohol-facilitating environments.

SCIENTIFIC SIGNIFICANCE

Findings add to the growing body of knowledge regarding genetic and social determinants of alcohol behaviors among college students of African descent. (Am J Addict 2017;26:349-356).

First description and evaluation of SNPs in the ADH and ALDH genes in a population of alcoholics in Central-West Brazil

Worldwide, different studies have reported an association of alcohol-use disorder (AUD) with different types of Single Nucleotide Polymorphisms (SNPs) in the genes for aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH). In Brazil, there is little information about the occurrence of these SNPs in the AUD population and an absence of studies characterizing the population in the Central-West Region of Brazil. Actually, in Brazil, there are more than 4 million people with AUD. Despite the major health hazards of AUD, information on alcohol consumption and its consequences are not well understood. Therefore, it is extremely important to characterize these SNPs for the better understanding of AUD as a genetic disease in the Brazilian population. The present study, unlike other studies in other countries, is done with a subject population that shows a significant amount of racial homogenization. We evaluated the presence of SNPs in the ADH (ADH1B, ADH1C, and ADH4) and ALDH (ALDH2) genes in alcohol users of Goiânia, State of Goiás - Brazil, and then we established a possible relationship with AUD by allelic and genotypic study. This study was conducted with a population of people with AUD (n = 99) from Goiás Alcohol Dependence Recovery Center (GO CEREA) and Psychosocial Care Center for Alcohol and Drugs (CAPS AD), and with a population of people without AUD as controls (n = 100). DNA was extracted from whole-blood samples and the genotyping was performed using TaqMan^® SNP genotyping assays. For characterization and evaluation of SNPs in the population, genotype frequency, allele frequency, haplotype frequency, Hardy-Weinberg equilibrium, and linkage disequilibrium were analyzed. Statistical analyses were calculated by GENEPOP 4.5 and Haploview software. The allele 1 was considered as "wild" (or *1) and allele 2 as mutant (or *2). Significant differences were found for ADH1B*, ADH4*2, and ALDH2*2 SNPs when the genotype and allele frequencies were analyzed. In addition, four haplotypes were observed between ADH1B*2 and ADH1C*2 through linkage disequilibrium analysis. The genetic variants may be associated with protection against AUD in the population studied.

ALDH2*2 and peer drinking in East Asian college students

BACKGROUND

The ALDH2*2 allele (A-allele) at rs671 is more commonly carried by Asians and is associated with alcohol-related flushing, a strong adverse reaction to alcohol that is protective against drinking. Social factors, such as having friends who binge drink, also contribute to drinking in Asian youth.

OBJECTIVES

This study examined the interplay between ALDH2*2, peer drinking, and alcohol consumption in college students. We hypothesized that the relationship between ALDH2*2 and standard grams of ethanol per month would vary based on the level of peer drinking.

METHODS

Subjects (N = 318, 63.25% female) were East Asian college students in the United States who reported drinking alcohol. Data were from the freshman year of a university survey that included a saliva DNA sample. ALDH2*2 status was coded ALDH2*2(+) (A/G and A/A genotypes) and ALDH2*2(-) (G/G genotype). Peer drinking was students' perception of how many of their friends "got drunk".

RESULTS

Main effects of ALDH2*2(-) and having more friends who got drunk were associated with greater alcohol consumption. The ALDH2*2 × peer drunkenness interaction showed a stronger positive association with alcohol consumption for ALDH2*2(-) versus ALDH2*2(+) at increasing levels of peer drunkenness. Follow-up comparisons within each peer drunkenness level identified significantly higher alcohol consumption for ALDH2*2(-) compared to ALDH2*2(+) at the all friends got drunk level.

CONCLUSION

There was evidence of a stronger effect for ALDH2*2(-) compared to ALDH2*2(+) with greater alcohol use when students were more exposed to peer drinking. Findings contribute to a growing literature on the interrelationships between genetic influences and more permissive environments for alcohol consumption.

Examination of associations between early life victimisation and alcohol's harm from others

INTRODUCTION AND AIMS

Study aims were to examine: (i) how physical and sexual victimisation in early life are associated with alcohol's harm from others; and (ii) whether respondents' current drinking is a mediator of the association between early life victimisation and alcohol's harm from others among men and women.

DESIGN AND METHODS

Data were from national computer-assisted telephone interviews, using the landline sample (3335 men and 3520 women ages ≥18) from the 2010 US National Alcohol Survey. Harms from someone else's drinking included family/marital problems, financial troubles, assault and vandalism in the past 12 months. Victimisation was measured with severe physical abuse or sexual assault before age 18.

RESULTS

Severe physical or sexual victimisation before age 18 was reported by 3.4% of men and 8.1% of women. Significantly more men (5.2%) than women (2.4%) reported assault by other drinkers, and significantly more women reported family/marital (5.3%) and financial problems (2.8%) than did men (2.6 and 1% respectively). Severe early life victimisation was robustly associated with a greater likelihood of experiencing past-year harms from other drinkers for both men and women. Men's drinking partially mediated associations between early life victimisation and recent assaults and vandalism by other drinkers.

DISCUSSION AND CONCLUSIONS

Early life victimisation may increase risk of harms from someone else's drinking. Health services and interventions that screen for histories of victimisation may help decrease risk of later harms from others' drinking. Reductions in drinking among men with histories of victimisation also could help reduce their exposure to such harms. [Kaplan LM, Greenfield TK, Karriker-Jaffe KJ. Examination of associations between early life victimisation and alcohol's harm from others.

Review: Environmental influences on alcohol use: Informing research on the joint effects of genes and the environment in diverse U.S. populations

BACKGROUND AND OBJECTIVES

This review aimed to inform the current state of alcohol research on the joint effects of genes and the environment conducted in U.S. racial/ethnic minority populations, focusing on African Americans, Latinos/Hispanics, Asians, and American Indians.

METHODS

A key-word and author-based search was conducted and supplemented with direct contact to researchers in this area to ensure a comprehensive inclusion of published, peer-reviewed studies. These studies were considered in terms of the racial/ethnic population groups, phenotypes, genetic variants, and environmental influences covered. Research findings from alcohol epidemiologic studies were highlighted to introduce some potential environmental variables for future studies of gene and environment (G-E) relationships.

RESULTS

Twenty-six (N = 26) studies were reviewed. They predominantly involved African American and Asian samples and had a very limited focus on Latinos/Hispanics and American Indians. There was a wide range of alcohol-related phenotypes examined, and studies almost exclusively used a candidate gene approach. Environmental influences focused on the most proximate social network relationships with family and peers. There was far less examination of community- and societal-level environmental influences on drinking. Epidemiologic studies informing the selection of potential environmental factors at these higher order levels suggest inclusion of indicators of drinking norms, alcohol availability, socioeconomic disadvantage, and unfair treatment.

CONCLUSIONS

The review of current literature identified a critical gap in the study of environments: There is the need to study exposures at community and societal levels.

SCIENTIFIC SIGNIFICANCE

These initial studies provide an important foundation for evolving the dialogue and generating other investigations of G-E relationships in diverse racial/ethnic groups. (Am J Addict 2017;26:446-460).

The Impact of Peer Substance Use and Polygenic Risk on Trajectories of Heavy Episodic Drinking Across Adolescence and Emerging Adulthood

BACKGROUND

Heavy episodic drinking is developmentally normative among adolescents and young adults, but is linked to adverse consequences in later life, such as drug and alcohol dependence. Genetic and peer influences are robust predictors of heavy episodic drinking in youth, but little is known about the interplay between polygenic risk and peer influences as they impact developmental patterns of heavy episodic drinking.

METHODS

Data were from a multisite prospective study of alcohol use among adolescents and young adults with genome-wide association data (n = 412). Generalized linear mixed models were used to characterize the initial status and slopes of heavy episodic drinking between age 15 and 28. Polygenic risk scores (PRS) were derived from a separate genome-wide association study for alcohol dependence and examined for their interaction with substance use among the adolescents' closest friends in predicting the initial status and slopes of heavy episodic drinking.

RESULTS

Close friend substance use was a robust predictor of adolescent heavy episodic drinking, even after controlling for parental knowledge and peer substance use in the school. PRS were predictive of the initial status and early patterns of heavy episodic drinking in males, but not in females. No interaction was detected between PRS and close friend substance use for heavy episodic drinking trajectories in either males or females.

CONCLUSIONS

Although substance use among close friends and genetic influences play an important role in predicting heavy episodic drinking trajectories, particularly during the late adolescent to early adult years, we found no evidence of interaction between these influences after controlling for other social processes, such as parental knowledge and broader substance use among other peers outside of close friends. The use of longitudinal models and accounting for multiple social influences may be crucial for future studies focused on uncovering gene-environment interplay. Clinical implications are also discussed.

Interactions Between Alcohol Metabolism Genes and Religious Involvement in Association With Maximum Drinks and Alcohol Dependence Symptoms

OBJECTIVE

Variations in the genes encoding alcohol dehydrogenase (ADH) enzymes are associated with both alcohol consumption and dependence in multiple populations. Additionally, some environmental factors have been recognized as modifiers of these relationships. This study examined the modifying effect of religious involvement on relationships between ADH gene variants and alcohol consumption-related phenotypes.

METHOD

Subjects were African American, European American, and Hispanic American adults with lifetime exposure to alcohol (N = 7,716; 53% female) from the Collaborative Study on the Genetics of Alcoholism. Genetic markers included ADH1Brs1229984, ADH1B-rs2066702, ADH1C-rs698, ADH4-rs1042364, and ADH4-rs1800759. Phenotypes were maximum drinks consumed in a 24-hour period and total number of alcohol dependence symptoms according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Religious involvement was defined by self-reported religious services attendance.

RESULTS

Both religious involvement and ADH1B-rs1229984 were negatively associated with the number of maximum drinks consumed and the number of lifetime alcohol dependence symptoms endorsed. The interactions of religious involvement with ADH1B-rs2066702, ADH1C-rs698, and ADH4-rs1042364 were significantly associated with maximum drinks and alcohol dependence symptoms. Risk variants had weaker associations with maximum drinks and alcohol dependence symptoms as a function of increasing religious involvement.

CONCLUSIONS

This study provided initial evidence of a modifying effect for religious involvement on relationships between ADH variants and maximum drinks and alcohol dependence symptoms.

Biology, Genetics, and Environment: Underlying Factors Influencing Alcohol Metabolism

Gene variants encoding several of the alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), are among the largest genetic associations with risk for alcohol dependence. Certain genetic variants (i.e., alleles)--particularly the ADH1B*2, ADH1B*3, ADH1C*1, and ALDH2*2 alleles--have been associated with lower rates of alcohol dependence. These alleles may lead to an accumulation of acetaldehyde during alcohol metabolism, which can result in heightened subjective and objective effects. The prevalence of these alleles differs among ethnic groups; ADH1B*2 is found frequently in northeast Asians and occasionally Caucasians, ADH1B*3 is found predominantly in people of African ancestry, ADH1C*1 varies substantially across populations, and ALDH2*2 is found almost exclusively in northeast Asians. Differences in the prevalence of these alleles may account at least in part for ethnic differences in alcohol consumption and alcohol use disorder (AUD). However, these alleles do not act in isolation to influence the risk of AUD. For example, the gene effects of ALDH2*2 and ADH1B*2 seem to interact. Moreover, other factors have been found to influence the extent to which these alleles affect a person's alcohol involvement, including developmental stage, individual characteristics (e.g., ethnicity, antisocial behavior, and behavioral undercontrol), and environmental factors (e.g., culture, religion, family environment, and childhood adversity).

Monoacylglycerol lipase (MGLL) polymorphism rs604300 interacts with childhood adversity to predict cannabis dependence symptoms and amygdala habituation: Evidence from an endocannabinoid system-level analysis

Despite evidence for heritable variation in cannabis involvement and the discovery of cannabinoid receptors and their endogenous ligands, no consistent patterns have emerged from candidate endocannabinoid (eCB) genetic association studies of cannabis involvement. Given interactions between eCB and stress systems and associations between childhood stress and cannabis involvement, it may be important to consider childhood adversity in the context of eCB-related genetic variation. We employed a system-level gene-based analysis of data from the Comorbidity and Trauma Study (N = 1,558) to examine whether genetic variation in six eCB genes (anabolism: DAGLA, DAGLB, NAPEPLD; catabolism: MGLL, FAAH; binding: CNR1; SNPs N = 65) and childhood sexual abuse (CSA) predict cannabis dependence symptoms. Significant interactions with CSA emerged for MGLL at the gene level (p = .009), and for rs604300 within MGLL (ΔR2 = .007, p < .001), the latter of which survived SNP-level Bonferroni correction and was significant in an additional sample with similar directional effects (N = 859; ΔR2 = .005, p = .026). Furthermore, in a third sample (N = 312), there was evidence that rs604300 genotype interacts with early life adversity to predict threat-related basolateral amygdala habituation, a neural phenotype linked to the eCB system and addiction (ΔR2 = .013, p = .047). Rs604300 may be related to epigenetic modulation of MGLL expression. These results are consistent with rodent models implicating 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid metabolized by the enzyme encoded by MGLL, in the etiology of stress adaptation related to cannabis dependence, but require further replication.

Genomewide Association Study for Maximum Number of Alcoholic Drinks in European Americans and African Americans

BACKGROUND

We conducted a genomewide association study (GWAS) for maximum number of alcoholic drinks consumed in a 24-hour period ("MaxDrinks"), in 2 independent samples comprised of over 9,500 subjects, following up on our GWAS for alcohol dependence (AD) in European Americans (EAs) and African Americans (AAs).

METHODS

The samples included our GWAS samples (Yale-UPenn) recruited for studies of the genetics of drug or AD, and a publicly available sample: the Study of Addiction: Genetics and Environment (SAGE). Genomewide association analysis was performed for ~890,000 single nucleotide polymorphisms (SNPs) using linear association random effects models. EAs and AAs were separately analyzed.

RESULTS

The results confirmed significant associations of the well-known functional loci at ADH1B with MaxDrinks in EAs (rs1229984 Arg48His p = 5.96 × 10(-15) ) and AAs (rs2066702 Arg370Cys, p = 2.50 × 10(-10) ). The region of significant association on chromosome 4 was extended to LOC100507053 in AAs but not EAs. We also identified potentially novel significant common SNPs for MaxDrinks in EAs in the Yale-UPenn sample: rs1799876 at SERPINC1 on chromosome 1 (4.00 × 10(-8) ) and rs2309169 close to ANKRD36 on chromosome 2 (p = 5.58 × 10(-9) ). After adjusting for the peak SNP rs1229984 on ADH1B, rs1799876 was nearly significant (p = 1.99 × 10(-7) ) and rs2309169 remained highly significant (2.12 × 10(-9) ).

CONCLUSIONS

The results provide further support that ADH1B modulates alcohol consumption. Future replications of potential novel loci are warranted. This is the largest MaxDrinks GWAS to date, the first in AAs.

The Alcohol Use Disorder and Associated Disabilities Interview Schedule-5 (AUDADIS-5): procedural validity of substance use disorders modules through clinical re-appraisal in a general population sample

BACKGROUND

The purpose of this study was to assess the procedural validity of the substance disorder modules of the lay-administered Alcohol Use Disorder and Associated Disabilities Interview Schedule, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Version (AUDADIS-5) through clinician re-appraisal re-interviews.

METHODS

The study employed a test-retest design among 712 respondents from the National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III). A clinician-administered, semi-structured interview, the Psychiatric Research Interview for Substance and Mental Disorders, DSM-5 version (PRISM-5) was used as the re-appraisal. Kappa coeffients indicated concordance of the AUDADIS-5 and PRISM-5 for DSM-5 substance use disorder diagnoses, while intraclass correlation coefficients (ICC) indicated concordance on dimensional scales indicating the DSM-5 criteria count for each disorder.

RESULTS

With few exceptions, concordance of the AUDADIS-5 and the PRISM-5 for DSM-5 diagnoses of substance use disorders ranged from fair to good (κ=0.40-0.72). Concordance on dimensional scales was excellent (ICC≥0.75) for the majority of DSM-5 SUD diagnoses, and fair to good (ICC=0.43-0.72) for most of the rest.

CONCLUSIONS

As indicated by concordance with a semi-structured clinician-administered re-appraisal, the procedural validity of the AUDADIS-5 DSM-5 substance use disorder diagnoses found in this study indicates that these AUDADIS-5 diagnoses are useful tools in epidemiologic studies. The considerably stronger concordance of the AUDADIS-5 and PRISM-5 dimensional DSM-5 SUD measures supports a current movement to place more emphasis on dimensional measures of psychopathology, and suggests that such measures may be more informative than binary diagnoses for research, and possibly for clinical purposes as well.

The Alcohol Use Disorder and Associated Disabilities Interview Schedule-5 (AUDADIS-5): reliability of substance use and psychiatric disorder modules in a general population sample

BACKGROUND

The purpose of this study was to assess the test-retest reliability of substance use disorder and psychiatric modules in the Alcohol Use Disorder and Associated Disabilities Interview Schedule, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Version (AUDADIS-5).

METHODS

Kappa and intraclass correlation coefficients were calculated for DSM-5 substance use and psychiatric disorder diagnoses and dimensional criteria scales using a test-retest design among 1006 respondents drawn from the National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III).

RESULTS

Reliabilities of substance use disorder diagnoses and associated criteria scales were generally good to excellent, while reliabilities for mood, anxiety and trauma and stress-related disorders and associated scales were generally in the fair to good range.

CONCLUSIONS

The observed reliability of the DSM-5 diagnoses and dimensional scales for the substance use and psychiatric disorders found in this study indicates that the AUDADIS-5 can be a useful tool in various research settings, particularly in studies of the general population, the target population for which it was designed.

The joint effects of ADH1B variants and childhood adversity on alcohol related phenotypes in African-American and European-American women and men

BACKGROUND

The ADH1B gene has consistently been implicated in problem drinking, but rarely incorporated into gene by environment investigations of alcohol phenotypes. This study examined the joint effects of variation in ADH1B and childhood adversity-a well-documented risk factor for alcohol problems and moderator of genetic liability to psychiatric outcomes-on maximum drinks consumed in a 24-hour period (maxdrinks) and alcohol use disorder (AUD) symptoms.

METHODS

Data were drawn from 2,617 African-American (AA) and 1,436 European-American (EA) participants (42% female) in a multisite genetic study of substance dependence. We tested the most significant ADH1B single nucleotide polymorphisms for alcohol dependence from a genomewide association study with this sample, ADH1B-rs1229984 (Arg48His) and ADH1B-rs2066702 (Arg370Cys), in EA and AA subsamples, respectively.

RESULTS

Ordinal regression analyses conducted separately by sex and population revealed significant main effects for childhood adversity for both alcohol phenotypes in AA women and men and for maxdrinks in EA women. A significant rs1229984 by childhood adversity interaction was observed for AUD symptoms in EA men. Unexposed His-allele carriers reported a mean of 3.6 AUD criteria, but adversity-exposed His-allele carriers endorsed approximately the same number (6.3) as those without the protective allele (6.3 and 7.0 for adversity-exposed and -unexposed groups, respectively).

CONCLUSIONS

Results suggest that under conditions of childhood adversity, the His allele does not exert its protective effects in EA men (OR = 0.57, CI: 0.32 to 1.01; p = 0.056). Findings highlight the robust risk effect conferred by childhood adversity and the importance of considering population and sex in genetically informative investigations of its association with alcohol outcomes.

The Genetics, Neurogenetics and Pharmacogenetics of Addiction

Addictions are prevalent psychiatric disorders that confer remarkable personal and social burden. Despite substantial evidence for their moderate, yet robust, heritability (approx. 50%), specific genetic mechanisms underlying their development and maintenance remain unclear. The goal of this selective review is to highlight progress in unveiling the genetic underpinnings of addiction. First, we revisit the basis for heritable variation in addiction before reviewing the most replicable candidate gene findings and emerging signals from genomewide association studies for alcohol, nicotine and cannabis addictions. Second, we survey the modest but growing field of neurogenetics examining how genetic variation influences corticostriatal structure, function, and connectivity to identify neural mechanisms that may underlie associations between genetic variation and addiction. Third, we outline how extant genomic findings are being used to develop and refine pharmacotherapies. Finally, as sample sizes for genetically informed studies of addiction approach critical mass, we posit five exciting possibilities that may propel further discovery (improved phenotyping, rare variant discovery, gene-environment interplay, epigenetics, and novel neuroimaging designs).