Leveraging genome-wide data to investigate differences between opioid use vs. opioid dependence in 41,176 individuals from the Psychiatric Genomics Consortium.

To provide insights into the biology of opioid dependence (OD) and opioid use (i.e., exposure, OE), we completed a genome-wide analysis comparing 4503 OD cases, 4173 opioid-exposed controls, and 32,500 opioid-unexposed controls, including participants of European and African descent (EUR and AFR, respectively). Among the variants identified, rs9291211 was associated with OE (exposed vs. unexposed controls; EUR z = -5.39, p = 7.2 × 10-8). This variant regulates the transcriptomic profiles of SLC30A9 and BEND4 in multiple brain tissues and was previously associated with depression, alcohol consumption, and neuroticism. A phenome-wide scan of rs9291211 in the UK Biobank (N > 360,000) found association of this variant with propensity to use dietary supplements (p = 1.68 × 10-8). With respect to the same OE phenotype in the gene-based analysis, we identified SDCCAG8 (EUR + AFR z = 4.69, p = 10-6), which was previously associated with educational attainment, risk-taking behaviors, and schizophrenia. In addition, rs201123820 showed a genome-wide significant difference between OD cases and unexposed controls (AFR z = 5.55, p = 2.9 × 10-8) and a significant association with musculoskeletal disorders in the UK Biobank (p = 4.88 × 10-7). A polygenic risk score (PRS) based on a GWAS of risk-tolerance (n = 466,571) was positively associated with OD (OD vs. unexposed controls, p = 8.1 × 10-5; OD cases vs. exposed controls, p = 0.054) and OE (exposed vs. unexposed controls, p = 3.6 × 10-5). A PRS based on a GWAS of neuroticism (n = 390,278) was positively associated with OD (OD vs. unexposed controls, p = 3.2 × 10-5; OD vs. exposed controls, p = 0.002) but not with OE (p = 0.67). Our analyses highlight the difference between dependence and exposure and the importance of considering the definition of controls in studies of addiction.

Associations of developmental imbalance between sensation seeking and premeditation in adolescence and heavy episodic drinking in emerging adulthood.

BACKGROUND: Dual systems theories suggest that greater imbalance between higher reward sensitivity and lower cognitive control across adolescence conveys risk for behaviors such as heavy episodic drinking (HED). Prior research demonstrated that psychological analogues of these systems, sensation seeking and premeditation, change from childhood through emerging adulthood, and each has been independently linked with HED. However, few studies have assessed whether change over time in these developing analogues is prospectively associated with HED. Moreover, we know of no research that has shown whether within-person differences between higher sensation seeking and relatively lower premeditation across the adolescent period predict HED in emerging adulthood. METHODS: Prospective data from the National Consortium on Alcohol and NeuroDevelopment in Adolescence study (n = 715) were used to examine the association of sensation seeking and premeditation with HED among adolescents ages 16 to 20 years. We used novel applications of latent difference score modeling and growth curve analysis to test whether increasing sensation seeking, premeditation, and their imbalance over time are associated with HED across the study period, and whether these associations differed by sex. RESULTS: Whereas premeditation increased linearly from adolescence through emerging adulthood across sexes, males reported growth and females reported decline in sensation seeking. Sensation seeking in adolescence (and not premeditation) was associated with higher levels of HED by emerging adulthood. Importantly, greater imbalance between sensation seeking and premeditation was associated with higher levels of HED by emerging adulthood though we note that variability capturing this imbalance correlated highly (r = 0.86) with baseline levels of sensation seeking. CONCLUSIONS: Developmental imbalance between higher sensation seeking and lower premeditation in late adolescence may be a risk factor for greater HED in emerging adulthood.

Meta-Analysis on Associations of Alcohol Metabolism Genes With Alcohol Use Disorder in East Asians.

AIMS: The current meta-analysis tested independent and composite associations of three commonly studied alcohol metabolism alleles with alcohol use disorder (AUD) within East Asians as well as characterized potential moderating factors in these associations. METHODS: For meta-analysis, 32 articles were selected that investigated ALDH2 (n = 17,755), ADH1B (n = 13,591) and ADH1C (n = 4,093) associations with AUD in East Asians. RESULTS AND CONCLUSIONS: All three variants were associated with AUD across allelic and genotypic models: ALDH2, ORs = 0.25, P < 0.001; ADH1B, ORs = 0.22-0.49, P < 0.001; ADH1C, ORs = 0.26-0.46, P < 0.001. Composite analyses suggested genetic associations did not differ across ALDH2*2 and ADH1B*2, correcting for multiple comparisons. Moderation analyses suggested ADH1B was more strongly associated with AUD among samples with cases recruited from treatment than the community. Also, strength of ALDH2 and/or ADH1B associations varied with mean age and proportion of men in cases and controls. Findings support medium to large and unique associations of ALDH2, ADH1B, and ADH1C with AUD in East Asians. Results also identified novel methodological and sample characteristics that may modulate strength of these associations.

Impulsivity Dimensions and Risky Sex Behaviors in an At-Risk Young Adult Sample.

Impulsivity is a personality-based risk factor that has been well studied in relation to risky sexual behavior. Recent conceptualizations of impulsivity have proposed multidimensional facets comprised of premeditation, perseverance, sensation seeking, negative urgency, and positive urgency (UPPS-P model). Prior studies have found that these facets are associated with risky sexual behavior in adolescent and college student samples, but no prior studies have evaluated them in clinical samples. The current study examined how impulsivity-related traits related to two different risky sexual behaviors in a clinical sample of at-risk young adults who had both conduct disorder and substance use disorder symptoms as adolescents (n = 529). Lack of premeditation was also tested as a moderator of the relationship between facets of impulsivity and both risky sex outcomes. Results demonstrated that sensation seeking, negative urgency, and positive urgency were correlated with risky sex behaviors. Additionally, multiple regression analyses indicated that sensation seeking was uniquely associated with the number of sexual partners in the past 5 years, whereas positive urgency was uniquely associated with unprotected sex while under the influence. Finally, a significant interaction between lack of premeditation and negative urgency suggests that at-risk young adults with both high negative urgency and lack of premeditation were the likeliest to have the most sexual partners in the past 5 years. This study adds to the current understanding of the relationship between reward- and affect-driven facets of impulsivity and risky sexual behaviors and may lend utility to the development of interventions for at-risk populations.

Positive expectancies mediate the association between sensation seeking and marijuana outcomes in at-risk young adults: A test of the acquired preparedness model.

BACKGROUND AND OBJECTIVES: The acquired preparedness model (APM) integrates personality trait research and psychosocial learning, which are theorized to ultimately increase risk for problematic substance use outcomes. METHODS: The present study uses the APM to examine the potential mediational role of positive and negative expectancies on the relationship between impulsivity and two marijuana outcomes (ie, frequency of use and marijuana use disorder [MUD] symptom count) among an at-risk sample of young adults with history of antisocial behavior and substance use in adolescence and their siblings (n = 312). RESULTS: Results suggest a significant indirect effect of sensation seeking on recent marijuana use through positive marijuana expectancies. There also was a significant indirect effect of sensation seeking on past-year MUD symptoms through positive expectancies. No significant indirect effects through negative expectancies were found for either outcome. DISCUSSION AND CONCLUSIONS: Our findings are consistent with the APM and suggest that higher sensation seeking is related to increased positive beliefs about marijuana outcomes, which is related to higher marijuana use and more MUD symptoms. SCIENTIFIC SIGNIFICANCE: These findings suggest that positive expectancies are an important risk factor for marijuana use and misuse, particularly for at-risk individuals with elevated rates of sensation seeking. Positive marijuana expectancies may be important to address in interventions for at-risk individuals. (Am J Addict 2018;XX:1-6).

Age of Drinking Initiation as a Risk Factor for Alcohol Use Disorder Symptoms is Moderated by ALDH2*2 and Ethnicity.

BACKGROUND: An early age of drinking initiation (ADI) has been associated with increased risk for alcohol use disorders (AUDs), but the consistency of this risk across diverse samples has not been well studied. The purpose of this study was to examine whether the pathway from ADI to AUD symptoms by early adulthood is moderated by ethnicity and possessing an alcohol-metabolizing gene ALDH2*2 variant allele. METHODS: We used multigroup structural equation modeling, including 5 groups split by ethnicity and ALDH2*2, to examine the consistency of the path from ADI to AUD symptoms in 604 Chinese-, Korean-, and White-American college students. We further examined the effects of ALDH2*2, ethnicity, and their interaction in Asians to better understand their unique contributions to the moderation. RESULTS: The association between ADI and AUD symptoms was moderated, with ADI negatively associated with AUD symptoms among Koreans without ALDH2*2 and Whites, but not among Koreans with ALDH2*2 or Chinese regardless of ALDH2*2. Both ALDH2*2 and ethnicity within Asians contributed unique variability in the effect. CONCLUSIONS: Ethnicity and ALDH2*2 altered the relationship of ADI as a risk factor for AUD symptoms. Being Chinese and possessing an ALDH2*2 allele within Koreans both buffered against the risk for AUD symptoms associated with earlier ADI, indicating that this relationship can be attenuated by protective factors.

Review: Prevalence and co-occurrence of addictions in US ethnic/racial groups: Implications for genetic research.

BACKGROUND AND OBJECTIVES: We conducted a review of the prevalence and co-occurrence of 12 types of addictions in US ethnic/racial groups and discuss the implications of the results for genetic research on addictions. METHODS: We utilized MEDLINE and PsycINFO databases to review the literature on alcohol, tobacco, marijuana, illicit drugs, gambling, eating/food, internet, sex, love, exercise, work, and shopping. We present results for each addiction based on total US prevalence, prevalence within ethnic groups, and co-occurrence of addictions among ethnic groups when available. RESULTS: This review indicates very little research has examined the interrelationships of addictive behaviors among US ethnic groups. The studies that exist have focused nearly exclusively on comorbidity of substances and gambling behaviors. Overall findings suggest differences among US ethnic groups in prevalence of addictions and in prevalence of addiction among those who use substances or engage in gambling. Almost no ethnic group comparisons of other addictive behaviors including eating/food, internet, love, sex, exercise, work, and shopping were identified in the literature. CONCLUSIONS: Despite large-scale research efforts to examine alcohol and substance use disorders in the United States, few studies have been published that examine these addictive behaviors among ethnic groups, and even fewer examine co-occurrence and comorbidity with other addictions. SCIENTIFIC SIGNIFICANCE: Even with the limited studies, these findings have implications for genetic research on addictive behaviors. We include a discussion of these implications, including issues of population stratification, disaggregation, admixture, and the interplay between genetic and environmental factors in understanding the etiology and treatment of addictions. (Am J Addict 2017;26:424-436).

Unique and interactive effects of impulsivity facets on reckless driving and driving under the influence in a high-risk young adult sample.

Risky driving behaviors are disproportionately high among young adults and impulsivity is a robust risk factor. Recent conceptualizations have proposed multidimensional facets of impulsivity comprised of negative urgency, premeditation, perseverance, sensation seeking, and positive urgency (UPPS-P model). Prior studies have found these facets are associated with risky driving behaviors in college student samples, but no prior studies have examined these facets in clinical samples. This study examined the unique and interactive effects of UPPS-P impulsivity facets on past-year risky driving behaviors in a sample of high-risk young adults (ages 18-30 years) with a history of substance use and antisocial behavior and their siblings (n=1,100). Multilevel Poisson regressions indicated that sensation seeking and negative urgency were uniquely and positively associated with both frequency of past-year reckless driving and driving under the influence. Moreover, lack of premeditation was uniquely and positively associated with reckless driving, whereas lack of perseverance was uniquely and positively associated with driving under the influence. Furthermore, lack of premeditation moderated and strengthened the positive association between sensation seeking and driving under the influence. These study findings suggest that assessing multiple facets of trait impulsivity could facilitate targeted prevention efforts among young adults with a history of externalizing psychopathology.

Gambling problems and comorbidity with alcohol use disorders in Chinese-, Korean-, and White-American college students.

BACKGROUND AND OBJECTIVES: This study examined gambling behaviors and the relationship between gambling problems and alcohol use disorders (AUDs) among Chinese-, Korean-, and White-American college students. METHODS: Participants were 678 (179 Chinese, 194 Korean, and 305 White; 50% female) 21-26 year-old (M = 22.0 ± 1.36) students attending one university in California. The South Oaks Gambling Screen was administered to assess gambling behavior and the Semi-Structured Assessment for the Genetics of Alcoholism was administered to diagnose lifetime AUDs. Chi-squares and multinomial logistic regressions were conducted to test our hypotheses. RESULTS: Rates of lifetime ever gambling and weekly gambling were similar across the three ethnic groups, but participation in five types of gambling behavior differed. Chinese had the highest rates of gambling problems followed by Koreans and then Whites. Univariate odds ratios determined being Chinese or Korean, being male, and having an AUD were risk factors for gambling problems. When stratified by gender and ethnicity, having an AUD was not related to gambling problems in women, but was strongly associated with gambling problems in Chinese and White men and modestly associated in Korean men. This was true despite low rates of AUDs in Chinese men. DISCUSSION AND CONCLUSIONS: Gambling problems were strongly comorbid with AUDs in Chinese- and White-American men, and moderately comorbid in Korean-American men. No relationship of AUD with gambling problems was found in women. SCIENTIFIC SIGNIFICANCE: The results highlight the importance of assessing disaggregated Asian-American subgroups with respect to addictive behaviors and their comorbidity.

The FKBP5 Gene Affects Alcohol Drinking in Knockout Mice and Is Implicated in Alcohol Drinking in Humans.

FKBP5 encodes FK506-binding protein 5, a glucocorticoid receptor (GR)-binding protein implicated in various psychiatric disorders and alcohol withdrawal severity. The purpose of this study is to characterize alcohol preference and related phenotypes in Fkbp5 knockout (KO) mice and to examine the role of FKBP5 in human alcohol consumption. The following experiments were performed to characterize Fkpb5 KO mice. (1) Fkbp5 KO and wild-type (WT) EtOH consumption was tested using a two-bottle choice paradigm; (2) The EtOH elimination rate was measured after intraperitoneal (IP) injection of 2.0 g/kg EtOH; (3) Blood alcohol concentration (BAC) was measured after 3 h limited access of alcohol; (4) Brain region expression of Fkbp5 was identified using LacZ staining; (5) Baseline corticosterone (CORT) was assessed. Additionally, two SNPs, rs1360780 (C/T) and rs3800373 (T/G), were selected to study the association of FKBP5 with alcohol consumption in humans. Participants were college students (n = 1162) from 21-26 years of age with Chinese, Korean or Caucasian ethnicity. The results, compared to WT mice, for KO mice exhibited an increase in alcohol consumption that was not due to differences in taste sensitivity or alcohol metabolism. Higher BAC was found in KO mice after 3 h of EtOH access. Fkbp5 was highly expressed in brain regions involved in the regulation of the stress response, such as the hippocampus, amygdala, dorsal raphe and locus coeruleus. Both genotypes exhibited similar basal levels of plasma corticosterone (CORT). Finally, single nucleotide polymorphisms (SNPs) in FKBP5 were found to be associated with alcohol drinking in humans. These results suggest that the association between FKBP5 and alcohol consumption is conserved in both mice and humans.

Development of a real-time repeated-measures assessment protocol to capture change over the course of a drinking episode.

AIMS: We report on the development of a real-time assessment protocol that allows researchers to assess change in BrAC, alcohol responses, behaviors, and contexts over the course of a drinking event. METHOD: We designed a web application that uses timed text messages (adjusted based on consumption pattern) containing links to our website to obtain real-time participant reports; camera and location features were also incorporated into the protocol. We used a transdermal alcohol sensor device along with software we designed to convert transdermal data into estimated BrAC. Thirty-two college students completed a laboratory session followed by a 2-week field trial. RESULTS: Results for the web application indicated we were able to create an effective tool for obtaining repeated measures real-time drinking data. Participants were willing to monitor their drinking behavior with the web application, and this did not appear to strongly affect drinking behavior during, or 6 weeks following, the field trial. Results for the transdermal device highlighted the willingness of participants to wear the device despite some discomfort, but technical difficulties resulted in limited valid data. CONCLUSION: The development of this protocol makes it possible to capture detailed assessment of change over the course of naturalistic drinking episodes.

Framing ethnic variations in alcohol outcomes from biological pathways to neighborhood context.

BACKGROUND: Health disparities research seeks to eliminate disproportionate negative health outcomes experienced in some racial/ethnic minority groups. This brief review presents findings on factors associated with drinking and alcohol-related problems in racial/ethnic groups. METHODS: Those discussed are as follows: (i) biological pathways to alcohol problems, (ii) gene × stress interactions, (iii) neighborhood disadvantage, stress, and access to alcohol, and (iv) drinking cultures and contexts. RESULTS: These factors and their interrelationships are complex, requiring a multilevel perspective. CONCLUSIONS: The use of interdisciplinary teams and an epigenetic focus are suggested to move the research forward. The application of multilevel research to policy, prevention, and intervention programs may help prioritize combinations of the most promising intervention targets.

Association of the ALDH1A1*2 promoter polymorphism with alcohol phenotypes in young adults with or without ALDH2*2.

BACKGROUND: Prior studies suggest a possible association of a promoter polymorphism in the ALDH1A1 gene ( ALDH1A1*2 ) with alcohol use or dependence. The aim of this study was to examine the association of ALDH1A1*2 with drinking behaviors in Asian young adults and to examine ALDH2 genotype as a potential moderator of these associations. METHODS: Asian young adults (n = 951) were recruited from 2 college sites for studies of genetic associations with alcohol use behavior. Participants completed comprehensive background questionnaires on demographics and drinking behavior. Fingertip blood samples were obtained for DNA extraction and analysis. RESULTS: Participants with the ALDH2*1/*2 genotype reported significantly lower levels (frequency and quantity) of drinking within the last 90 days, fewer numbers of heavy drinking episodes within the last 90 days, and lower lifetime maximum consumption levels compared with ALDH2*1/*1 participants. There were no significant main effects of ALDH1A1*2 on any drinking variables, nor was there a significant interaction between ALDH2 and ALDH1A1 genotypes on drinking outcomes. CONCLUSIONS: The association of ALDH2*2 with reduced alcohol consumption replicates previous findings across numerous studies. Although ALDH1A1*2 was not associated with drinking levels, the lack of an ALDH1A1*2 effect in ALDH2*2 individuals is consistent with the only other study that has examined these associations in East Asian populations.

Evaluating a cognitive model of ALDH2 and drinking behavior.

BACKGROUND: Despite evidence for genetic influences on alcohol use and alcohol-related cognitions, genetic factors and endophenotypes are rarely incorporated in cognitive models of drinking behavior. This study evaluated a model of ALDH2 and drinking behavior stipulating cognitive factors and alcohol sensitivity as accounting for genetic influences on drinking outcomes. METHODS: Participants were Asian-American young adults (n = 171) who completed measures of alcohol cognitions (drinking motives, drinking refusal self-efficacy, and alcohol expectancies), alcohol sensitivity, drinking behavior, and alcohol-related problems as part of a prospective study. Structural equation modeling (SEM) evaluated a model of drinking behavior that stipulated indirect effects of ALDH2 on drinking outcomes through cognitive variables and alcohol sensitivity. RESULTS: The full model provided an adequate fit to the observed data, with the measurement model explaining 63% of the variance in baseline heavy drinking and 50% of the variance in alcohol-related problems at follow-up. Associations of ALDH2 with cognitive factors and alcohol sensitivity were significant, whereas the association of ALDH2 with drinking was not significant with these factors included in the model. Mediation tests indicated significant indirect effects of ALDH2 through drinking motives, drinking refusal self-efficacy, and alcohol sensitivity. CONCLUSIONS: Results are consistent with the perspective that genetic influences on drinking behavior can be partly explained by learning mechanisms and implicate cognitive factors as important for characterizing associations of ALDH2 with drinking.

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.

Familial factors may not explain the effect of moderate-to-heavy cannabis use on cognitive functioning in adolescents: a sibling-comparison study.

AIMS: To examine whether moderate adolescent cannabis use has neurocognitive effects that are unexplained by familial confounds, which prior family-controlled studies may not have identified. DESIGN: A quasi-experimental, sibling-comparison design was applied to a prospective, observational study of adolescents with moderate cannabis use. Participants were recruited from 2001 to 2006 (mean age = 17 years). A second wave of data was collected from 2008 to 2013 (mean age = 24 years). SETTING: Two US metropolitan communities. PARTICIPANTS: A total of 1192 adolescents from 596 families participated in this study. Participants were primarily male (64%) and racially and ethnically diverse (non-Hispanic white = 45%). A sibling in each family was a clinical proband identified due to delinquent behaviors. Whereas prior family-controlled studies have used samples of primarily infrequent cannabis users (mean = 1-2 days/month), participants here endorsed levels of cannabis use comparable to findings from epidemiological cohort studies (mean = 7-9 days/month). MEASUREMENTS: Semi-structured clinical interviews assessed drug use, and a neuropsychological battery assessed cognitive abilities. Covariates included age at assessment, gender and alcohol use. FINDINGS: After correcting for multiple testing, a greater frequency and earlier onset of regular cannabis use were associated with poorer cognitive performance, specifically on tests of verbal memory. Further, after accounting for familial factors shared by siblings and alcohol use, poorer verbal memory performance was still associated with greater life-time frequency of cannabis use at wave 1 [b = -0.007 (-0.002, -0.012), adjusted P = 0.036]; earlier cannabis use at wave 2 [b = -0.12 (-0.05, -0.19), adjusted P = 0.006; b = -0.14 (-0.06, -0.23), adjusted P = 0.006]; and greater frequency of past 6 months use at wave 2 [b = -0.02 (-0.01, -0.03), adjusted P = 0.002; b = -0.02 (-0.01, -0.03), adjusted P = 0.008]. CONCLUSIONS: Moderate adolescent cannabis use may have adverse effects on cognitive functioning, specifically verbal memory, that cannot be explained by familial factors.

Sleep deficits and cannabis use behaviors: an analysis of shared genetics using linkage disequilibrium score regression and polygenic risk prediction.

STUDY OBJECTIVES: Estimate the genetic relationship of cannabis use with sleep deficits and an eveningness chronotype. METHODS: We used linkage disequilibrium score regression (LDSC) to analyze genetic correlations between sleep deficits and cannabis use behaviors. Secondly, we generated sleep deficit polygenic risk score (PRS) and estimated their ability to predict cannabis use behaviors using linear and logistic regression. Summary statistics came from existing genome-wide association studies of European ancestry that were focused on sleep duration, insomnia, chronotype, lifetime cannabis use, and cannabis use disorder (CUD). A target sample for PRS prediction consisted of high-risk participants and participants from twin/family community-based studies (European ancestry; n = 760, male = 64%; mean age = 26.78 years). Target data consisted of self-reported sleep (sleep duration, feeling tired, and taking naps) and cannabis use behaviors (lifetime ever use, number of lifetime uses, past 180-day use, age of first use, and lifetime CUD symptoms). RESULTS: Significant genetic correlation between lifetime cannabis use and an eveningness chronotype (rG = 0.24, p < 0.001), as well as between CUD and both short sleep duration (<7 h; rG = 0.23, p = 0.017) and insomnia (rG = 0.20, p = 0.020). Insomnia PRS predicted earlier age of first cannabis use (OR = 0.92, p = 0.036) and increased lifetime CUD symptom count (OR = 1.09, p = 0.012). CONCLUSION: Cannabis use is genetically associated with both sleep deficits and an eveningness chronotype, suggesting that there are genes that predispose individuals to both cannabis use and sleep deficits.

ADH1B*3 and response to alcohol in African-Americans.

BACKGROUND: Variations in the alleles for the alcohol-metabolizing enzymes have been shown to influence risk for alcohol dependence. One variant, ADH1B*3, is observed almost exclusively in populations of African ancestry and has been shown to be associated with reduced rates of alcohol dependence. We conducted an alcohol challenge study to test whether ADH1B*3 is associated with differences in subjective and physiological response to alcohol. METHOD: We administered a moderate dose of alcohol (0.72 g/kg for males, 0.65 g/kg for females) to a sample of African-American young adults (n = 91; ages 21 to 26). Participants were genotyped for ADH1B, as well as additional polymorphisms that might contribute to alcohol response. Breath alcohol concentration, self-reported sedation and stimulation, and pulse rate were assessed prior to alcohol administration and for 2.5 hours following administration. RESULTS: ADH1B*3 was associated with higher levels of sedation and a sharper increase in pulse rate immediately following alcohol consumption. CONCLUSIONS: These findings suggest that the lower rates of alcohol dependence in those with ADH1B*3 alleles may be because of differences in alcohol response, particularly increased sedation.

Evaluation of a brief web-based genetic feedback intervention for reducing alcohol-related health risks associated with ALDH2.

There is increasing interest in health interventions that incorporate genetic risk information. Although genetic feedback has been evaluated as an adjunct to smoking cessation interventions, its efficacy for reducing alcohol-related risks is unknown. The purpose of this study was to evaluate the feasibility, acceptability, and efficacy of a web-based alcohol intervention incorporating genetic feedback and risk information specific to ALDH2 genotype. The ALDH2*2 variant is associated with partial protection against alcohol dependence but confers significantly increased risk for alcohol-related cancers as a function of alcohol exposure. Two hundred Asian-American young adults were randomly assigned to receive web-based personalized genetic feedback or attention-control feedback. Genetic feedback included health risk information specific to alcohol-related cancer or alcohol dependence, depending on genotype. Outcomes included postintervention drinking behavior and theoretical correlates of behavior change. Genetic feedback and risk information resulted in significant reductions in 30-day drinking frequency and quantity among participants with the ALDH2*1/*2 genotype. Genetic feedback was rated highly by participants and also showed some effects on theoretical correlates of behavior change. Results provide initial evidence of the feasibility, acceptability, and brief efficacy of web-based genetic feedback for reducing alcohol-related health risks associated with ALDH2 genotype.

Associations of ALDH2 and ADH1B genotypes with alcohol-related phenotypes in Asian young adults.

BACKGROUND: Associations of ALDH2 and ADH1B genotypes with alcohol use have been evaluated largely using case-control studies, which typically focus on adult samples and dichotomous diagnostic outcomes. Relatively fewer studies have evaluated ALDH2 and ADH1B in relation to continuous drinking outcomes or at different developmental stages. This study examined additive and interactive effects of ALDH2 and ADH1B genotypes on drinking behavior in a mixed-gender sample of Asian young adults, focusing on continuous phenotypes (e.g., heavy episodic and hazardous drinking, alcohol sensitivity, drinking consequences) whose expression is expected to precede the onset of alcohol use disorders. METHODS: The sample included 182 Chinese- and Korean-American young adults ages 18 years and older (mean age = 20 years). Effects of ALDH2, ADH1B and ethnicity were estimated using generalized linear modeling. RESULTS: The ALDH2*2 allele predicted lower reported rates of alcohol use and drinking consequences as well as greater reported sensitivity to alcohol. There were significant ethnic group differences in drinking outcomes, such that Korean ethnicity predicted higher drinking rates and lower alcohol sensitivity. ADH1B status was not significantly related to drinking outcomes. CONCLUSIONS: Ethnicity and ALDH2 status, but not ADH1B status, consistently explained significant variance in alcohol consumption in this relatively young sample. Results extend previous work by showing an association of ALDH2 genotype with drinking consequences. Findings are discussed in the context of possible developmental and population differences in the influence of ALDH2 and ADH1B variations on alcohol-related phenotypes.