ALDH2 Status, Alcohol Expectancies, and Alcohol Response: Preliminary Evidence for a Mediation Model

Drinking experience uncovers genetic influences on alcohol expectancies across adolescence

AIMS

To test whether drinking onset moderates genetic and environmental contributions to individual differences in the etiology of alcohol expectancies across adolescence.

DESIGN

Longitudinal twin design.

SETTING

Community sample from Los Angeles, CA, USA.

PARTICIPANTS

A total of 1292 male and female twins, aged 11–18years, were assessed at 1 (n = 440), 2 (n = 587) or 3 (n = 265) occasions as part of the risk factors for the Antisocial Behavior Twin Study.

MEASUREMENTS

Social behavioral (SB) alcohol expectancies were measured using an abbreviated version of the Social Behavioral subscale from the Alcohol Expectancy Questionnaire for adolescents (AEQ-A). Drinking onset was defined as >1 full drink of alcohol.

FINDINGS

Alcohol expectancies increased over age and the increase became more rapid following onset of drinking. The importance of genetic and environmental influences on SB scores varied with age and drinking status, such that variation prior to drinking onset was attributed solely to environmental influences, whereas all post-onset variation was attributed to genetic influences. Results did not differ significantly by sex.

CONCLUSION

Only environmental factors explain beliefs about the social and behavioral consequences of alcohol use prior to drinking onset,whereas genetic factors explain an increasing proportion of the variance in these beliefs after drinking onset.

A framework for the specificity of addictions

Research over the last two decades suggests that a wide range of substance and behavioral addictions may serve similar functions. Yet, co-occurrence of addictions has only been reported among a minority of addicts. "Addiction specificity" pertains to a phenomenon in which one pattern of addictive behaviors may be acquired whereas another is not. This paper presents the PACE model as a framework which might help explain addiction specificity. Pragmatics, attraction, communication, and expectation (PACE) variables are described, which may help give some direction to future research needs in this arena.

Incapacitated rape and alcohol use in White and Asian American college women

This study examined the role of Asian ethnicity as a moderator of drinking outcomes associated with alcohol-related sexual assault (incapacitated rape). Participants were 5,467 Asian American and White college women. Results found the overall MANOVA for ethnicity and incapacitated rape (IR) interactions to be significant. Asian American participants with no history of IR had fewer drinking problems than White American participants with no history of IR. Asian American participants with IR histories had more drinking problems than White Americans with IR histories. Findings indicate Asian Americans who experience IR may be at increased risk for negative alcohol outcomes.

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.

The A1 allele of the D2 dopamine receptor gene region, alcohol expectancies and drinking refusal self-efficacy are associated with alcohol dependence severity

Psychological risk and genetic risk for alcohol dependence are rarely examined in concert. The current study used path analysis (via structural equation modelling) to explore the relationship between the A(1) allele of the D2 dopamine receptor DRD2 gene region, age of problem drinking onset, alcohol expectancy and drinking refusal self-efficacy towards alcohol consumption and dependence severity. One hundred and forty-three (93 male, 50 female) alcohol dependent inpatients provided an extensive clinical history, including age of onset of problem drinking and quantity and frequency of alcohol consumption. The Drinking Expectancy Profile and the Alcohol Dependence Scale were completed, and 10 milliliters of blood were obtained for genetic analysis. The results showed that the posited model fitted the data set well and support the pattern of direct (allele status to drinking) and indirect (allele status influenced by psychosocial variables) relationships hypothesised for the model. A formal test of mediation showed some support for a psychosocial mediational model. The results are discussed in terms of a possible developmental trajectory that involves both genetic risk that influences brain dopamine activity and reinforcement expectancies that both operate via diminished drinking refusal self-efficacy. The prevention and treatment possibilities that arise from understanding this trajectory are examined.

Drinking expectancies and motives: a genetic study of young adult women

BACKGROUND

Constructs such as drinking expectancies (beliefs regarding the effects of alcohol) and motives (drinking alcohol to achieve a valued end) have been shown to be associated with various stages of alcohol use behaviors. However, little is known of the extent to which genetic and environmental influences contribute to individual differences in expectancies and motives.

METHODS

Using data from 3,656 young adult same-sex female twins, we examined the association between measures of drinking expectancies and motives and drinking behaviors. Using twin models, we estimated the extent to which genetic, shared and non-shared environmental factors influenced individual differences in expectancies and motives and also tested whether the extent of the genetic and environmental contributions on expectancies varied across abstainers and users of alcohol.

RESULTS

Expectancies predicted initiation of alcohol use. Both motives and expectancies were associated with frequency and quantity of alcohol consumption and drinks-to-intoxication. There was no evidence for heritable influences on expectancies and enhancement motives, with familial similarity for these traits being due to shared environment. Heritable influences on social, coping and conformity motives ranged from 11% to 33%. When expectancies were stratified by alcohol use, significant heritable influences (31-39%) were found for cognitive-behavioral impairment and risk-taking/negative self-perception (RT/NSP) in abstainers only, while environmental influences contributed to familial variance for other measures of expectancies in alcohol users.

CONCLUSIONS

Environmental influences (both familial and individual-specific) shape alcohol expectancies, while heritable influences may predispose to motives for drinking. Individual differences in expectancies are moderated by alcohol use, suggesting that sources of individual differences in expectancies may vary in drinkers versus abstainers.

[Factors influencing juvenile alcohol consumption: the role of gene-environment interactions]

INTRODUCTION

Excessive alcohol consumption in youth increases the risk of subsequent alcohol use disorders. Despite the recognition of genetic and environmental factors, an appropriate aetiological model is needed to take adequate preventative steps. This is in part due to the complex interactions between genotype and environment. In this article we review research on factors determining alcohol use by adolescents and on the development of an unifying model.

METHOD

The data bank Medline Advanced was searched for topical articles that were then checked for relevance and sorted according to genetic factors, environmental factors, and their interactions.

RESULTS

Many factors, alone and in combination with others, influence juvenile alcohol consumption. Each single variable, however, can explain only a small part of the variation in consumption behaviour.

CONCLUSION

The manifold possibilities of interactions between these factors become clear. There is a strong need for comprehensive models of juvenile alcohol use and the integration of current results into these models.

The role of drug use outcome expectancies in substance abuse risk: an interactional-transformational model

While a variety of risk factors for substance abuse have been identified, the psychological mechanisms underlying the transmission of risk is unclear based on studies using traditional risk-outcome research designs. The present paper identifies drug use outcome expectancies as a common etiological mechanism involved in substance abuse risk. Existing literature findings are reviewed and integrated according to an interactional-transformational (IT) model of developmental psychopathology. This model identifies the preliminary (mediating) and secondary (moderating) role of drug expectancies as important operations involved in the development of substance use patterns. Advantages of the IT model over traditional trait-based or environmental models are discussed, along with implications for intervention and future research.

Is the Strength of Implicit Alcohol Associations Correlated with Alcohol-induced Heart-rate Acceleration?

BACKGROUND

Heart rate (HR) acceleration during the ascending limb of the blood alcohol curve has proven to be a reliable measure of the sensitivity to the activating effects of alcohol. In this study, we investigated the correlation between an ethanol-induced cardiac change and the strength of implicit alcohol-related arousal and approach associations and attentional bias for alcohol-related stimuli in heavy drinkers. These 3 types of implicit alcohol-related cognitions have been proposed to reflect the strength of incentive sensitization that is experienced after repeated alcohol use.

METHODS

Forty-eight heavy drinking men performed a modified version of the Implicit Association Test (IAT) to measure their implicit alcohol arousal and approach-avoidance associations. A modified version of the emotional Stroop was used to measure attentional bias for alcohol-related stimuli (blocked and unblocked). Next, a high dose of alcohol (1.0 mL/kg body weight 95% USP alcohol) was administered in a short period of time. Resting baseline HR, blood alcohol concentrations, mood, and craving for alcohol were assessed before alcohol administration and for 2 hours post-alcohol consumption.

RESULTS

Contrary to our hypothesis, a negative association was found between implicit arousal associations and alcohol-induced HR change. This indicates that strong arousal associations were correlated with a decrease in alcohol-induced HR. Approach associations and attentional bias were not correlated with alcohol-induced HR change, but both were correlated positively with each other.

CONCLUSIONS

Alcohol-arousal associations and other implicit cognitions (attentional bias, approach associations) are not positively related to individual differences in the sensitivity to alcohol's activating effects, at least not in the present sample consisting primarily of family history-negative heavy drinkers.

Alcohol-related expectancies are associated with the D2 dopamine receptor and GABAA receptor beta3 subunit genes

Molecular genetic research has identified promising markers of alcohol dependence, including alleles of the D2 dopamine receptor (DRD2) and the GABAA receptor beta3 subunit (GABRB3) genes. Whether such genetic risk manifests itself in stronger alcohol-related outcome expectancies, or in difficulty resisting alcohol, is unknown. In the present study, A1+ (A1A1 and A1A2 genotypes) and A1- (A2A2 genotype) alleles of the DRD2 and G1+ (G1G1 and G1 non-G1 genotypes) and G1- (non-G1 non-G1 genotype) alleles of the GABRB3 gene were determined in a group of 56 medically ill patients diagnosed with alcohol dependence. Mood-related alcohol expectancy (AE) and drinking refusal self-efficacy (DRSE) were assessed using the Drinking Expectancy Profile (Manual for the Drinking Expectancy Profile, Behaviour Research and Therapy Centre, Brisbane, 1996). Patients with the DRD2 A1+ allele, compared with those with the DRD2 A1- allele, reported significantly lower DRSE in situations of social pressure. Similarly, lower DRSE was reported under social pressure by patients with the GABRB3 G1+ allele when compared to those with the GABRB3 G1- alleles. Patients with the GABRB3 G1+ allele also revealed reduced DRSE in situations characterized by negative affect than those with the GABRB3 G1- alleles. Patients carrying the GABRB3 G1+ allele showed stronger AE relating to negative affective change (for example, increased depression) than their GABRB3 G1- counterparts. Biological influence in the development of some classes of cognitions is hypothesized. The clinical implications, particularly with regard to patient-treatment matching and the development of an integrated psychological and pharmacogenetic approach, are discussed.