Individual differences in subjective response to alcohol have been implicated as a risk factor for the development of alcohol use disorders. There are, however, a variety of ethical, legal, and practical considerations surrounding alcohol administration studies which limit the extent to which this marker can be used to identify those believed to be at greater risk. The current research contains two related laboratory studies with the overall goal of identifying valid and reliable correlates of individual differences in subjective response to alcohol that can be used to discern emerging adults at greater risk for problematic drinking. Study 1 evaluated the associations between the actual subjective experience of a moderate dose of alcohol (BAC .08%) and three domains of potential correlates: anticipated subjective response based on a hypothetical drinking scenario (targeted .08% BAC); response to other physiological and perceptual challenges (e.g., CO2 challenge, spinning challenge); and indices of cognitive impairment implicated as risk factors for the development of alcohol use disorders. Study 2 examined each of these domains in relation to transitions in heavy drinking from high school to college to determine whether they were associated with changes in relative risk during this developmental period. Overall, the results provide support for the utility of examining individual differences in subjective response to alcohol based on a hypothetical drinking scenario. The evidence suggests that experienced drinkers are capable of reliably and accurately estimating their subjective response to alcohol, that these anticipated effects are distinct from general beliefs about the effects of alcohol on behavior (i.e., alcohol expectancies), and that they are associated with patterns of drinking in emerging adults. There was little evidence to suggest that individual differences in subjective response to alcohol were associated with subjective response to other physiological or perceptual challenges, or patterns of cognitive impairment previously shown to be related to an increased risk for alcohol dependence. The results of the current study support the utility of using measures of anticipated subjective response as a proxy for individual differences in subjective response to alcohol when the administration of alcohol is either not appropriate or feasible.

Variability in subjective response to alcohol has been shown to predict drinking behavior as well as the development of alcohol use disorders. The current study examined the extent to which individual differences in alcohol pharmacokinetics impact subjective response and drinking behavior during a single session alcohol administration paradigm. Participants (N = 98) completed measures of subjective response at two time points following alcohol consumption. Pharmacokinetic properties (rate of absorption and metabolism) were inferred using multiple BAC readings to calculate the area under the curve during the ascending limb for absorption and descending limb for metabolism. Following the completion of the subjective response measures, an ad-libitum taste rating task was implemented in which participants were permitted to consume additional alcoholic beverages. The amount consumed during the taste rating task served as the primary outcome variable. Results of the study indicated that participants who metabolized alcohol more quickly maintained a greater level of subjective stimulation as blood alcohol levels declined and reported greater reductions in subjective sedation. Although metabolism did not have a direct influence on within session alcohol consumption, a faster metabolism did relate to increased ad-libitum consumption indirectly through greater acute tolerance to sedative effects and greater maintenance of stimulant effects. Rate of absorption did not significantly predict subjective response or within session drinking. The results of the study add clarity to theories of subjective response to alcohol, and suggest that those at highest risk for alcohol problems experience a more rapid reduction in sedation following alcohol consumption while simultaneously experiencing heightened levels of stimulation. Variability in pharmacokinetics, namely how quickly one metabolizes alcohol, may be an identifiable biomarker of subjective response and may be used to infer risk for alcohol problems.

Sensitivity to the effects of alcohol has long been studied as a risk factor for developing an alcohol use disorder. Several theories exist regarding the profile of subjective responses that constitute the highest risk: Two of the most prominent are the Low Level of Response and Differentiator Models. A newer model focused on craving for alcohol, the Dual Process Model, suggests that craving may be correlated to the risky patterns of response predicted by the Low Level of Response and Differentiator Models. Relatively little research up to this point has focused on whether the responses predicted by these models generalize beyond the laboratory. The present study focuses on how individual differences in response to alcohol during the course of naturalistic drinking episodes map onto those laboratory-based theories. Participants from Project Six of the Midwest Alcoholism Research Center recorded their responses to alcohol and when randomly prompted by an electronic diary for 21 days. Three sets of analyses were conducted: examining responses following the first drink of an episode relative to a random prompt, as well as while estimated blood alcohol content was ascending and descending. The Low Level of Response Model enjoyed the highest degree of support in the data. The observed pattern of craving responses did not clearly match either the Low Level of Response or Differentiator Models

Levels of heavy episodic drinking peak during emerging adulthood and contribute to the experience of negative consequences. Previous research has identified a number of trait-like personality characteristics that are associated with drinking. Studies of the Acquired Preparedness Model have supported positive expectancies, and to a lesser extent negative expectancies, as mediators of the relation between trait-like characteristics and alcohol outcomes. However, expectancies measured via self-report may reflect differences in learned expectancies in spite of similar alcohol-related responses, or they may reflect true individual differences in subjective responses to alcohol. The current study addressed this gap in the literature by assessing the relative roles of expectancies and subjective response as mediators within the APM in a sample of 236 emerging adults (74.7% male) participating in a placebo-controlled alcohol challenge study. The study tested four mediation models collapsed across beverage condition as well as eight separate mediation models with four models (2 beverage by 2 expectancy/subjective response) for each outcome (alcohol use and alcohol-related problems). Consistent with previous studies, SS was positively associated with alcohol outcomes in models collapsed across beverage condition. SS was also associated with positive subjective response in collapsed models and in the alcohol models. The hypothesized negative relation between SS and sedation was not significant. In contrast to previous studies, neither stimulation nor sedation predicted either weekly drinking or alcohol-related problems. While stimulation and alcohol use appeared to have a positive and significant association, this relation did not hold when controlling for SS, suggesting that SS and stimulation account for shared variability in drinking behavior. Failure to find this association in the placebo group suggests that, while explicit positive expectancies are related to alcohol use after controlling for levels of sensation seeking, implicit expectancies (at least as assessed by a placebo manipulation) are not. That the relation between SS and stimulation held only in the alcohol condition in analyses separate by beverage condition indicates that sensation seeking is a significant predictor of positive subjective response to alcohol (stimulation), potentially above and beyond expectancies.

The question how alcohol alters mood states and why this may end up becoming an addiction is puzzling alcohol researchers since decades. In this volume, an assembly of highly distinguished experts and leaders in alcohol addiction research provides lucid presentations of the current knowledge and research challenges as well as interesting viewpoints on future research directions aimed to stimulate communication and convergence between clinical and preclinical researchers, and to renew interest in the vibrant field of alcohol addiction research among a wide scientifically minded audience. Five Current Topics are discussed in this volume: Neurobiological mechanisms of alcoholism, Genetics, Clinical phenotypes and their preclinical models, Brain imaging, and Translational approaches for treatment development, both pharmacological and non-pharmacological. These areas have in our opinion brought alcohol research substantially forward and influenced our thinking about how to reach our common paramount goal, namely to offer effective treatment solutions for an extensive group of patients with largely unmet medical needs.