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A key feature of circadian rhythms is the sleep/wake cycle. Sleep causes reduced responsiveness to the environment, which puts animals in a particularly vulnerable state; yet sleep has been conserved throughout evolution, indicating that it fulfils a vital purpose. A core function of sleep across species has not been identified, but substantial advances in sleep research have been made in recent years using the genetically tractable model organism, Drosophila melanogaster. This review describes the universality of sleep, the regulation of sleep, and current theories on the function of sleep, highlighting a historical and often overlooked theory called the Free Radical Flux Theory of Sleep. Additionally, we summarize our recent work with short-sleeping Drosophila mutants and other genetic and pharmacological tools for manipulating sleep which supports an antioxidant theory of sleep and demonstrates a bi-directional relationship between sleep and oxidative stress., (© 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Introduction and Aims: This study tested the measurement invariance of the Drinking Motives Questionnaire-Revised Short Form (DMQ-R-SF) in undergraduates across 10 countries. We expected the four-factor structure to hold across countries, and for social motives to emerge as the most commonly endorsed motive, followed by enhancement, coping and conformity motives. We also compared individualistic and collectivistic countries to examine potential differences in the endorsement of drinking motives when countries were divided according to this broad cultural value., Design and Methods: A sample of 8478 undergraduate drinkers from collectivistic (Portugal, Mexico, Brazil, Spain; n = 1567) and individualistic (Switzerland, Hungary, Canada, the Netherlands, the UK and Ireland, and the USA; n = 6911) countries completed the DMQ-R-SF. Countries were classified as individualistic or collectivistic based on world-wide norms., Results: Using multigroup confirmatory factor analysis, the 4-factor model of the DMQ-R-SF showed configural and metric invariance across all 10 countries. As predicted, the rank order of undergraduates' drinking motive endorsement was identical across countries (social > enhancement > coping > conformity), although a mixed model analysis of variance revealed a significant interaction where undergraduates from individualistic countries more strongly endorsed social and enhancement motives relative to undergraduates from collectivistic countries., Discussion and Conclusions: There was broad cross-cultural consistency in the factor structure and mean patterns of drinking motives. Undergraduate students appear to drink mainly for positive reinforcement (i.e. for social and enhancement reasons), although this tendency is particularly pronounced among those from more individualistic countries. [Mackinnon SP, Couture M-E, Cooper ML, Kuntsche E, O'Connor RM, Stewart SH, and the DRINC Team. Cross-cultural comparisons of drinking motives in 10 countries: Data from the DRINC project., (© 2017 Australasian Professional Society on Alcohol and other Drugs.)

Background: There is great interest in the role of the behavioral inhibition system (BIS) and the behavioral approach system (BAS) in the etiology of alcohol use because of the strong links of these systems to neuroscience and cognitive models of addiction. The revised Reinforcement Sensitivity Theory suggests that the strength of the BIS and BAS jointly influences behavior, so-called the joint systems hypothesis. Yet, relatively little work has examined this hypothesis, particularly with respect to alcohol information processing. Grounded in dual-process theories of alcohol information processing, this study aimed to clarify the roles of implicit (i.e., automatic processes) and explicit (i.e., controlled processes) cognitions in BIS-related drinking. When anxious and presented with an alcohol (vs. neutral) cue, we expected those with an elevated BIS to have increased implicit and explicit alcohol cognitions related to tension reduction, but only at elevated BAS. Shifts in cognitions following cue exposure were expected to positively correlate with alcohol misuse., Methods: Students (N = 110) completed baseline measures followed by the Trier Social Stress Test. This was followed by a cue exposure (random assignment to alcohol or water cue), during which participants completed postmood assessments of implicit/explicit alcohol cognitions., Results: Overall, participants' implicit alcohol cognition was negative. The effect of BIS on implicit and explicit cognitions was moderated by BAS; however, results were not as hypothesized. In the alcohol condition only (when controlling for baseline implicit cognition), BIS predicted relatively weak implicit negative alcohol cognition, but only at low BAS. Interestingly, in the alcohol condition only, BIS predicted increased explicit reward (but not relief) expectancies, but only at high BAS. Changes in explicit reward expectancies positively correlated with alcohol misuse., Conclusions: Our results suggest that explicit cognitions may be relevant to drinking among anxious individuals who are also reward responsive. Cognitive behavioral interventions should target reward expectancies to reduce anxiety-related drinking., (Copyright © 2016 by the Research Society on Alcoholism.)

Background: Undergraduate students experience diverse problems because of alcohol use. Accordingly, the Young Adult Alcohol Consequences Questionnaire (YAACQ) was developed to assess multiple domains of alcohol-related problems. A preliminary psychometric evaluation in a U.S. college sample showed support for 8 factors that were invariant across gender and that loaded onto a single higher-order alcohol-related problems factor. Supporting concurrent validity, this preliminary work also found that YAACQ total scores correlated with heavy alcohol use. While these results are promising, the factor structure of the YAACQ has yet to be replicated. This goal of this study was to test the psychometrics of the YAACQ in a large Canadian student sample. Invariance across gender, year of study, place of residence, and relative drinking level was examined. Correlations between the YAACQ subscales and alcohol use measures were investigated to test concurrent validity., Methods: Students (N = 1,103, 80% women) completed online self-reports., Results: Results from a confirmatory factor analysis (CFA) supported an 8-factor lower-order structure, with all factors loading onto a single higher-order alcohol-related problems factor. Multigroup CFAs supported measurement invariance across gender, year of study, place of residence, and relative drinking level. YAACQ subscales were positively correlated with weekly alcohol use and binge drinking., Conclusions: Our study provides an important replication of the psychometrics of the YAACQ in a new sample, and we extend previous work by presenting novel tests of measurement invariance across meaningful groups in young adulthood. Overall, our study suggests that the 48-item YAACQ is a valid measure of alcohol-related problems in Canadian students., (Copyright © 2016 by the Research Society on Alcoholism.)

Background: In response to conflicting reward (Behavioral Approach System [BAS]) and/or punishment cues (Fight-Flight-Freeze System [FFFS]) the Behavioral Inhibition System (BIS) inhibits behavior, leading to increased attention to threat, high anxiety, and behavioral ambivalence. The role of BIS in alcohol misuse is complex, as anxiety promotes self-medication drinking, while attention to threat (e.g., negative outcomes of heavy drinking) may reduce risk. Theory suggests that a concurrent strong BAS may bias BIS-conflict in favor of alcohol approach, while a concurrent strong FFFS may increase the likelihood of alcohol avoidance. However, few studies measure BIS as a conflict system, and no studies incorporate such a measure into examinations of alcohol misuse. Our study goals were to (i) test the Motivational Flanker Task (MFT) as a new laboratory measure of the BIS, BAS, and FFFS; and (ii) use the MFT, in conjunction with self-report measures, to test BAS and FFFS as moderators of the BIS-alcohol misuse relation. We hypothesized that an elevated BIS would predict heavy drinking and alcohol-related problems, but only when BAS was high. Further, we expected an elevated BIS to be associated with reduced alcohol misuse, but only when FFFS was high., Methods: Students (N = 198) completed self-reports of BIS/BAS/FFFS and drinking behavior, and 2 reaction time tasks: MFT and Point Scoring Reaction Time Task (PSRTT). The PSRTT is a published measure of the revised BIS., Results: MFT BIS conflict was associated with self-report and PSRTT measures. MFT BAS, but not FFFS, was associated with self-reports. As expected, elevated BIS was associated with heavy drinking, but only when BAS-Drive and BAS-Fun Seeking was also high. FFFS was not supported as a moderator of the BIS-alcohol misuse association., Conclusions: Results support the MFT as a promising measure of the revised BIS. Considering the joint effects of BIS and BAS clarified risk for alcohol misuse., (Copyright © 2014 by the Research Society on Alcoholism.)