Initial development of a measure of expectancies for combinations of alcohol and caffeine: the Caffeine + Alcohol Combined Effects Questionnaire (CACEQ)

Alcohol Mixed with Energy Drinks (AmED) Use among University Students: A Systematic Review and Meta-Analysis

In the last decades, there has been a huge increase in the consumption of both Energy Drinks (EDs) and alcohol and, concurrently, these two trends generated the additional practice of mixing ED with alcohol, known as Alcohol mixed with Energy Drink (AmED). One of the most important group of AmED consumers is represented by young. Indeed, the study population of the researches in this field are mainly represented by college students and the results evidence a great range of negative consequences for health. The purpose of the systematic review was to explore the prevalence of AmED consumption among undergraduate students, together with motivations to their use, adverse effects and health-related behaviors associated to AmEDs use. The review was conducted according to the PRISMA Statement and PubMed, Scopus and Web of Science were interrogated. 42 articles, published from 2008 to 2021, were included in the review. An overall prevalence rate of 37% was estimated for AmEDs use in undergraduates, with geographical differences. Although a decrease in consumption was observed throughout the studied period, a continuous monitoring on this phenomenon is needed for identifying those risk groups that could develop risky behaviors related to AmEDs consumption and provide them targeted educational interventions.

Alcohol Use and Problems in Daily and Non-Daily Coffee Drinking College Females

BACKGROUND

For more than a decade, a large proportion of research on caffeine use in college students has focused on energy drinks (ED), demonstrating an association between ED consumption and heavy/problem alcohol use. The present study examined the relationship between daily coffee consumption and varied measures of alcohol use and problems in a sample of college women.

METHODS

Participants were undergraduate females (N=360) attending an urban university in 2001-02 and prior to the rise in ED popularity on college campuses. Analyses compared women who reported drinking coffee daily (DC; 16.9%), to women who did not (NDC; 83.1%) on standardized measures of alcohol use and problems.

RESULTS

For both past month and year of drinking, DC women generally reported consuming more alcohol and were 2.1-2.6 times more likely to screen at risk for alcohol problems than their NDC counterparts. DC women were also more likely than NDC women to report problems related to drinking (e.g., experiencing blackouts, inability to stop drinking after they had started).

CONCLUSIONS

Findings support potential benefits of health education and screening that goes beyond EDs, focusing on varied forms of caffeine consumption.

Behavioral effects of the combined use of alcohol and energy drinks on alcohol hangover in an experimental mice model

In last few years it has been a significant increase in the consumption of alcohol combined with energy drink. The aim of this work was to study the effect of this mixture in motor and affective behaviors during an alcohol hangover episode. Male Swiss mice received one of the following treatments: saline + sucrose; saline + energy drink; ethanol + sucrose; ethanol + energy drink. Ethanol dose was 3.8 g/kg BW (i.p.) and energy drink dose was 18 ml/kg BW (gavage) at ZT1 (8 am) (ZT: Zeitgeber time; ZT0: 7 am; lights on). The behavioral tests used were tight rope test to determine motor coordination; hanging wire test to study muscular strength; elevated plus maze and open field tests to evaluate anxiety like-behavior and locomotor activity. Tests were carried out at basal point that matched with lights onset and every 6 h up to 18 h after treatments. Hangover onset was established at ZT7 when blood alcohol concentration (BAC) was almost zero. Our results showed that the mixture of alcohol and energy drink altered significantly motor skills. Specifically, a significant decrease was observed in the performance of the animals in the tightrope and hanging wire tests in groups treated with the mixture of alcohol and energy drink. A significant impairment in the anxiety-like behavior was observed mainly at the beginning of alcohol hangover. These findings suggest that energy drink added to alcohol extends motor disabilities observed during an alcohol hangover episode in comparison with animals that received alcohol alone.

Alcohol-Induced Impairment of Balance is Antagonized by Energy Drinks

BACKGROUND

The acute administration of alcohol reliably impairs balance and motor coordination. While it is common for consumers to ingest alcohol with other stimulant drugs (e.g., caffeine, nicotine), little is known whether prototypical alcohol-induced balance impairments are altered by stimulant drugs. The purpose of this study was to examine whether the coadministration of a high-caffeine energy drink with alcohol can antagonize expected alcohol-induced increases in body sway.

METHODS

Sixteen social drinkers (of equal gender) participated in 4 separate double-blind dose administration sessions that involved consumption of alcohol and energy drinks, alone and in combination. Following dose administration, participants completed automated assessments of balance stability (both eyes open and eyes closed) measured using the Biosway Portable Balance System. Participants completed several subjective measures including self-reported ratings of sedation, stimulation, fatigue, and impairment. Blood pressure and pulse rate were recorded repeatedly.

RESULTS

The acute administration of alcohol increased body sway, and the coadministration of energy drinks antagonized this impairment. When participants closed their eyes, alcohol-induced body sway was similar whether or not energy drinks were ingested. While alcohol administration increased ratings of sedation and fatigue, energy drink administration increased ratings of stimulation and reduced ratings of fatigue. Modest increases in systolic and diastolic blood pressure following energy drink administration were also observed.

CONCLUSIONS

Visual assessment of balance impairment is frequently used to indicate that an individual has consumed too much alcohol (e.g., as part of police-standardized field sobriety testing or by a bartender assessing when someone should no longer be served more alcohol). The current findings suggest that energy drinks can antagonize alcohol-induced increases in body sway, indicating that future work is needed to determine whether this observation regarding neuromotor functioning applies to alcohol in combination with all types of stimulant drugs.

Nature versus intensity of intoxication: Co-ingestion of alcohol and energy drinks and the effect on objective and subjective intoxication

BACKGROUND

We report a series of studies examining the effect of alcohol mixed with energy drinks (AmEDs) versus alcohol on objective intoxication (breath alcohol concentration; BrAC), intensity, and nature of intoxication. We also aimed to disentangle the role of energy drink (ED) ingredients in any effects.

METHOD

Three within-subject double-blind placebo-controlled studies measured BrAC, subjective intoxication and impairment ('intensity of intoxication'), stimulation and sedation ('nature of intoxication') following administration of ED, Cola, Caffeine+Sugar, and Placebo with alcohol (Study 1, n=18); ED, Caffeine-only, Sugar-only and Placebo with alcohol (Study 2, n=20); and ED and Placebo with alcohol (Study 3, n=27).

RESULTS

Significant moderate-to-large magnitude BrAC decrements and delayed time to peak BrAC were observed after ED administration versus Placebo. However, no meaningful BrAC differences between ED and other active conditions were observed in Study 1 and 2. After BrAC adjustment, moderate-to-large magnitude reductions in intoxication and impairment ratings were observed after ED versus Placebo on the ascending limb in all studies and at peak in Study 2 and 3. No meaningful differences were observed in intoxication and impairment ratings between ED and Caffeine+Sugar and Cola conditions (Study 1); ratings were lower after ED versus Sugar-only (Study 2). Stimulation and sedation ratings did not differ between ED and Placebo.

CONCLUSION

Reductions in objective intoxication and perceived intensity of intoxication, but not nature of intoxication, were observed after AmED consumption. However, effects may be common to alcohol mixers containing sugars (objective intoxication) and caffeine (intensity of intoxication) and specific to a laboratory setting.

A daily diary examination of caffeine mixed with alcohol among college students

OBJECTIVE

Caffeinated alcoholic beverage (CAB) use is associated with a range of substance-related problems. The majority of prior research on CABs is based on cross-sectional and retrospective reports, which do not account for intraindividual differences in use and may be subject to recall biases. The current research used a daily diary, within-subjects design to compare days where individuals simultaneously mixed alcohol with caffeine (CAB days) and days where individuals drank other types of alcohol (non-CAB days) on alcohol use outcomes. These relationships were tested further by examining the impact of the type of mixer (i.e., energy drink or cola-caffeinated).

METHOD

Participants were 122 (73.8% women) heavy drinking, college student CAB users. Mean age was 20.39 (SD = 2.08) years. Students completed a baseline questionnaire and up to 14 consecutive daily surveys about the previous night's drinking behavior.

RESULTS

Multilevel modeling results indicated that CAB days were associated with heavier alcohol use, regardless of mixer type. In addition, beyond amount of alcohol consumed the previous night and trait impulsivity, CAB days were linked with more alcohol-related problems, but only when the mixer was an energy drink. CAB days did not differ from non-CAB days on driving or sex after drinking.

CONCLUSIONS

This study was the first to demonstrate the unique risks posed by simultaneously consuming caffeine and alcohol in a within-subjects, daily diary design. Future research investigating use patterns may benefit from the use of fine-grained approaches in order to provide information relevant for CAB prevention and intervention efforts. (PsycINFO Database Record

Intoxication-Related Alcohol Mixed with Energy Drink Expectancies Scale: Initial Development and Validation

BACKGROUND

Young adult use of alcohol mixed with energy drinks (AmEDs) has been linked with elevated risks of a constellation of problem behaviors. These risks may be conditioned by expectancies regarding the effects of caffeine in conjunction with alcohol consumption. The aim of this study was to describe the construction and psychometric evaluation of the Intoxication-Related AmED Expectancies Scale (AmED_EXPI), 15 self-report items measuring beliefs about how the experience of AmED intoxication differs from the experience of noncaffeinated alcohol (NCA) intoxication.

METHODS

Scale development and testing were conducted using data from a U.S. national sample of 3,105 adolescents and emerging adults aged 13 to 25. Exploratory and confirmatory factor analyses were conducted to evaluate the factor structure and establish factor invariance across gender, age, and prior experience with AmED use. Cross-sectional and longitudinal analyses examining correlates of AmED use were used to assess construct and predictive validity.

RESULTS

In confirmatory factor analyses, fit indices for the hypothesized 4-factor structure (i.e., Intoxication Management [IM], Alertness [AL], Sociability [SO], and Jitters [JT]) revealed a moderately good fit to the data. Together, these factors accounted for 75.3% of total variance. The factor structure was stable across male/female, teen/young adult, and AmED experience/no experience subgroups. The resultant unit-weighted subscales showed strong internal consistency and satisfactory convergent validity. Baseline scores on the IM, SO, and JT subscales predicted changes in AmED use over a subsequent 3-month period.

CONCLUSIONS

The AmED_EXPI appears to be a reliable and valid tool for measuring expectancies about the effects of caffeine during alcohol intoxication.

Effects of caffeine on alcohol reinforcement: beverage choice, self-administration, and subjective ratings

RATIONALE

Combining alcohol and caffeine is associated with increased alcohol consumption, but no prospective experimental studies have examined whether added caffeine increases alcohol consumption.

OBJECTIVES

This study examined how caffeine alters alcohol self-administration and subjective reinforcing effects in healthy adults.

METHODS

Thirty-one participants completed six double-blind alcohol self-administration sessions: three sessions with alcohol only (e.g., beverage A) and three sessions with alcohol and caffeine (e.g., beverage B). Participants chose which beverage to consume on a subsequent session (e.g., beverage A or B). The effects of caffeine on overall beverage choice, number of self-administered drinks, subjective ratings (e.g., Biphasic Alcohol Effects Scale), and psychomotor performance were examined.

RESULTS

A majority of participants (65%) chose to drink the alcohol beverage containing caffeine on their final self-administration session. Caffeine did not increase the number of self-administered drinks. Caffeine significantly increased stimulant effects, decreased sedative effects, and attenuated decreases in psychomotor performance attributable to alcohol. Relative to nonchoosers, caffeine choosers reported overall lower stimulant ratings and reported greater drinking behavior prior to the study.

CONCLUSIONS

Although caffeine did not increase the number of self-administered drinks, most participants chose the alcohol beverage containing caffeine. Given the differences in subjective ratings and pre-existing differences in self-reported alcohol consumption for caffeine choosers and nonchoosers, these data suggest that decreased stimulant effects of alcohol and heavier self-reported drinking may predict subsequent choice of combined caffeine and alcohol beverages. These predictors may identify individuals who would benefit from efforts to reduce risk behaviors associated with combining alcohol and caffeine.

Faster self-paced rate of drinking for alcohol mixed with energy drinks versus alcohol alone

The consumption of alcohol mixed with energy drinks (AmED) has been associated with higher rates of binge drinking and impaired driving when compared with alcohol alone. However, it remains unclear why the risks of use of AmED are heightened compared with alcohol alone even when the doses of alcohol consumed are similar. Therefore, the purpose of this laboratory study was to investigate if the rate of self-paced beverage consumption was faster for a dose of AmED versus alcohol alone using a double-blind, within-subjects, placebo-controlled study design. Participants (n = 16) of equal gender who were social drinkers attended 4 separate test sessions that involved consumption of alcohol (1.97 ml/kg vodka) and energy drinks, alone and in combination. On each test day, the dose assigned was divided into 10 cups. Participants were informed that they would have a 2-h period to consume the 10 drinks. After the self-paced drinking period, participants completed a cued go/no-go reaction time (RT) task and subjective ratings of stimulation and sedation. The results indicated that participants consumed the AmED dose significantly faster (by ∼16 min) than the alcohol dose. For the performance task, participants' mean RTs were slower in the alcohol conditions and faster in the energy-drink conditions. In conclusion, alcohol consumers should be made aware that rapid drinking might occur for AmED beverages, thus heightening alcohol-related safety risks. The fast rate of drinking may be related to the generalized speeding of responses after energy-drink consumption. (PsycINFO Database Record

A Preliminary Investigation of Caffeinated Alcohol Use During Spring Break

BACKGROUND

Caffeinated alcoholic beverages (e.g., Red Bull and vodka) are popular but associated with negative consequences. CABs may be particularly popular during Spring Break, a potentially risky social event.

OBJECTIVES

We aimed to identify the prevalence of Spring Break caffeinated alcohol use, determine how caffeinated alcohol use Spring Break drinking habits differ from usual, and examine the association between Spring Break caffeinated alcohol use and alcohol-related problems.

METHODS

Data were collected from 95 college students during March of 2013 and 2014. Students completed questionnaires of their alcohol and caffeinated alcohol use before and during Spring Break and Spring Break alcohol-related problems.

RESULTS

Approximately 54% of students used caffeinated alcohol during Spring Break. Spring Break caffeinated alcohol use was associated with more alcohol-related problems, even after controlling for other alcohol consumed and Spring Break vacation status.

CONCLUSIONS/IMPORTANCE

Caffeinated alcoholic beverages are commonly consumed during Spring Break and their use uniquely predicted harms. Prevention efforts placed on caffeinated alcoholic beverage users may be helpful in reducing Spring Break-related harms.

Expert testimony in sexual assault cases: Alcohol intoxication and memory

At court-martial tribunals in the United States military, cases involving alcohol facilitated sexual assault often pivot on the alleged victim's level of intoxication or impairment and ability to consent to the sexual act. These cases frequently arise following a night of partying and heavy drinking among a group of friends and acquaintances, military and civilian. The determination of whether a sexual act was consensual may rest on estimates of the alleged victim's blood alcohol concentration and related behavioral indicia of impairment. Expert testimony may be presented by the prosecution and/or the defense, from forensic toxicologists and psychiatrists or psychologists regarding the potential involvement of alcohol and its impact on the participants relevant to the charges at court-martial. A review of the state of the science is offered to bring such testimony into perspective. Appellate cases illustrate that the experts' testimony may sometimes elucidate, sometimes obfuscate, and sometimes exceed professional expertise and invade the province of the factfinder.

Testing a model of caffeinated alcohol-specific expectancies

INTRODUCTION

The present study sought to further understand the association between caffeinated alcoholic beverage (CAB) use and alcohol-related risks. In particular, we focused on the role of two identified expectancies specific to CAB use: intoxication enhancement and avoidance of negative consequences. Although outcome expectancies are consistent predictors of substance use, limited research has examined expectancies related to CAB use and their association with alcohol-related behaviors, such as protecting themselves from alcohol-related harms. Consequently, the present study examined CAB-specific expectancies and protective behavioral strategies (PBS) as mediators of CAB use and negative consequences.

METHODS

Participants were 322 (219 women) college drinkers who completed self-report measures of typical CAB and alcohol use, CAB-specific expectancies, PBS use, and alcohol-related harms.

RESULTS

Structural equation modeling revealed, after controlling for typical non-CAB heavy alcohol use, a significant indirect effect of CAB use to alcohol-related problems through avoidance of negative consequences CAB expectancies and PBS use. However, intoxication enhancement expectancies did not mediate this association.

CONCLUSIONS

Our findings indicate that heavier CAB use was associated with stronger expectations that drinking CABs can help avoid negative consequences. These beliefs were related to using fewer PBS when drinking and a greater likelihood of experiencing problems. Given that these expectancies may be underlying mechanisms of CAB use, their inclusion in existing alcohol interventions may be beneficial.

A comprehensive review of the effects of mixing caffeinated energy drinks with alcohol

BACKGROUND

In response to concern about whether mixing caffeinated energy drinks with alcohol (AED) increases alcohol consumption and related harm, and the role of industry in this debate, we conducted a comprehensive review of the research evidence on the effects of AED and documented industry involvement in this research.

METHOD

A systematic review of 6 databases. Studies must have examined the effect of consuming alcohol with energy drinks (ED) or caffeine on alcohol-related outcomes.

RESULTS

62 studies were identified; 29 were experiments, 9 had industry ties (8 with Red Bull GmbH). Young adults who consumed AED drank more alcohol and experienced more alcohol-related harm than other drinkers. There was insufficient evidence to conclude that AED led to increased alcohol consumption or altered the nature of alcohol-related harm. However, AED consumers reported that AED increased stimulation and alertness, offset fatigue from drinking, and facilitated drinking. Experimental research also found that combining ED or caffeine with alcohol increased stimulation and alertness, offset alcohol-related fatigue and increased the desire to keep drinking. It did not change BAC, perceived intoxication, perceived impairment and it did not reverse alcohol-induced impairment on simple psychomotor tasks. Combining ED/caffeine with alcohol reduced alcohol-induced impairment on some but not all aspects of complex tasks. Although few in number, studies with industry ties presented contrary evidence.

CONCLUSION

A growing body of evidence suggests that AED may facilitate drinking and related harms via its effects on intoxication but a causal link needs to be confirmed. The influence of industry involvement in this area of research needs to be monitored.

Caffeinated alcohol use and expectancies for caffeine versus alcohol

BACKGROUND

Caffeinated alcoholic beverage (CAB) use is related to alcohol-related risk. Limited research has examined outcome expectancies and CAB consumption.

OBJECTIVES

This study tested the predictive utility of caffeine and alcohol expectancies in CAB use outcomes (i.e. quantity, frequency, and alcohol-related harms).

METHODS

Participants were 419 (302 women) alcohol and caffeine users from a mid-sized urban university. Data collection occurred between August 2010 and December 2011. Participants completed measures of caffeine and alcohol expectancies, alcohol problems, alcohol use, and CAB use.

RESULTS

Caffeine and alcohol expectancies contributed uniquely to approximately 12% of the variability in quantity, 8% in frequency, and 16% in problems. When examined separately, alcohol expectancies explained approximately 10% to 11% of the variance, whereas caffeine expectancies accounted for 6% of the variance in CAB use quantity. For CAB use frequency, alcohol and caffeine expectancies accounted for about 8% and 4%, respectively. Alcohol expectancies accounted for 12% to 14% of variance, whereas caffeine expectancies accounted for 4% to 6% in alcohol-related harms. CONCLUSIONS/ IMPORTANCE: The present study sought to address a gap in the literature regarding the contributions of expectancies in the prediction of CAB use. Our findings provide support for the predictive utility of both caffeine and alcohol expectancies in accounting for individual variability in CAB use but alcohol expectancies may exert greater impact on use patterns. Inclusion of both types of expectancies in larger theoretical frameworks may be beneficial in gaining a more complete and deeper conceptualization of this risky behavior.

Effects of alcohol and energy drink on mood and subjective intoxication: a double-blind, placebo-controlled, crossover study

OBJECTIVE

There is concern that combining energy drinks with alcohol may 'mask' subjective intoxication leading to greater alcohol consumption. This study examines the effects of alcohol alone and combined with energy drink on objective and subjective intoxication and mood over the course of 3 h.

METHOD

Using a double-blind, placebo-controlled, balanced, crossover design, 24 participants (mean age 22.23 years) were administered with double placebo, 0.6 g/kg alcohol (mean peak blood alcohol content of 0.051%), 250 ml energy drink and alcohol/energy drink, according to a Latin square design, with a washout of >48 h. On each visit, they were breathalysed and rated themselves on a comprehensive battery of mood items at baseline and then at 45, 90 and 180 min post-drink.

RESULTS

Blood alcohol and subjective intoxication were significantly increased following both alcohol alone and alcohol/energy drink. Both measures were statistically indistinguishable between alcohol conditions. In keeping with its (80 mg) caffeine content, the energy drink alone significantly increased self-rated 'alertness' and reduced 'depression-dejection' scores compared with the combined alcohol/energy drink. The alcohol/energy drink increased 'vigor' and 'contentment' at 45 min and decreased 'contentment' at 180 min.

CONCLUSIONS

The co-ingestion of an energy drink with alcohol does not differently influence blood alcohol content recordings or subjective intoxication compared with alcohol alone, although some mood items are differentially affected.

Effects of caffeinated vs. non-caffeinated alcoholic beverage on next-day hangover incidence and severity, perceived sleep quality, and alertness

AIMS

Beliefs about the effects of mixing caffeine and alcohol on hangover or sleep may play a role in motivation to consume these mixtures; therefore, information is needed about actual effects. We investigated whether intoxication with caffeinated vs. non-caffeinated beer differentially affected perceived sleep quality, sleepiness, and hangover incidence and severity the next morning.

METHODS

University students (89%) and recent graduate drinkers were randomized to receive: (1) beer with the equivalent of 69mg caffeine/12oz glass of regular beer (n=28) or (2) beer without caffeine (n=36), in sufficient quantity to attain a BrAC of 0.12g%. After an 8-h supervised sleep period, participants completed measures of hangover, sleep quality, sleep latency and time asleep, and sleepiness.

RESULTS

While caffeinated beer improved perceived sleep quality, effect sizes were greater for morning alertness than for quality while sleeping, with no effect on sleep latency or total sleep time. No effects were seen on hangover incidence or severity.

CONCLUSIONS

Mixing caffeine and alcohol does not significantly impair amount of sleep or sleep latency, hangover, or sleepiness the morning after drinking to intoxication in this population.

Caffeinated alcohol consumption profiles and associations with use severity and outcome expectancies

Growing evidence suggests that the consumption of caffeinated alcoholic beverages (CAB) may be riskier than alcohol alone. Efforts to identify patterns of CAB use and the correlates of such drinking patterns could further our conceptualization of and intervention for this health issue. Consequently, the current study aimed to (1) identify distinct classes of CAB users, (2) examine differences between classes on measures of alcohol and caffeine problems, and (3) compare distinct classes of CAB users on caffeine and alcohol outcome expectancies. Participants were 583 (31% men) undergraduate students from a psychology research pool. Latent profile analysis models were derived using four indicators: CAB use quantity, CAB use frequency, alcohol use quantity, and alcohol use frequency. Finding revealed four classes of drinkers: High Alcohol/High CAB (6.00%), High Alcohol/Moderate CAB (5.15%), High Alcohol/Low CAB (22.99%), and Low Alcohol/Low CAB (65.87%). The Low Alcohol/Low CAB class reported the lowest relative levels of caffeine dependence symptoms, caffeine withdrawal, alcohol use problems, and heavy episodic drinking frequency. Further, results indicated differential expectancy endorsement based on use profiles. CAB users in the High Alcohol/Low CAB class endorsed more positive alcohol expectancies than the Low Alcohol/Low CAB group. Those in the High Alcohol/High CAB class endorsed stronger withdrawal symptom caffeine expectancies than all other classes. Inclusion of substance-specific expectancies into larger theoretical frameworks in future work of CAB use may be beneficial. Findings may inform intervention efforts for those at greatest risk related to CAB consumption.

Impulsivity and alcohol demand in relation to combined alcohol and caffeine use

Problematic alcohol use among college students continues to be a prominent concern in the United States, including the growing trend of consuming caffeinated alcoholic beverages (CABs). Epidemiologically, CAB use is associated with incremental risks from drinking, although these relationships could be due to common predisposing factors rather than specifically due to CABs. This study investigated the relationship between CAB use, alcohol misuse, and person-level characteristics, including impulsive personality traits, delayed reward discounting, and behavioral economic demand for alcohol use. Participants were 273 regularly drinking undergraduate students. Frequency of CAB use was assessed over the past month. A multidimensional assessment of impulsivity included the UPPS-P questionnaire, which measures positive and negative urgency, premeditation (lack thereof), perseverance (lack thereof), and sensation seeking (Lynam, Smith, Whiteside, & Cyders, 2007), and a validated questionnaire-based measure of delayed reward discounting. Demand was assessed via a hypothetical alcohol purchase task. Frequency of CAB consumption was significantly higher in men than in women and was also associated with higher impulsivity on the majority of the UPPS-P subscales, steeper delayed reward discounting, and greater demand for alcohol. Significant correlations between CAB use and both alcohol demand and lack of premeditation remained present after including level of alcohol misuse in partial correlations. In a hierarchical linear regression incorporating demographic, demand, and impulsivity variables, CAB frequency continued to be a significant predictor of hazardous alcohol use. These results suggest that although there are significant associations between CAB consumption and gender, impulsivity, and alcohol demand, CAB use continues to be associated with alcohol misuse after controlling for these variables.

Caffeinated Alcoholic Beverages - An Emerging Trend in Alcohol Abuse

Alcohol use disorders are pervasive in society and their impact affects quality of life, morbidity and mortality, as well as individual productivity. Alcohol has detrimental effects on an individual’s physiology and nervous system, and is associated with disorders of many organ and endocrine systems impacting an individual’s health, behavior, and ability to interact with others. Youth are particularly affected. Unfortunately, adolescent usage also increases the probability for a progression to dependence. Several areas of research indicate that the deleterious effects of alcohol abuse may be exacerbated by mixing caffeine with alcohol. Some behavioral evidence suggests that caffeine increases alcohol drinking and binge drinking episodes, which in turn can foster the development of alcohol dependence. As a relatively new public health concern, the epidemiological focus has been to establish a need for investigating the effects of caffeinated alcohol. While the trend of co-consuming these substances is growing, knowledge of the central mechanisms associated with caffeinated ethanol has been lacking. Research suggests that caffeine and ethanol can have additive or synergistic pharmacological actions and neuroadaptations, with the adenosine and dopamine systems in particular implicated. However, the limited literature on the central effects of caffeinated ethanol provides an impetus to increase our knowledge of the neuroadaptive effects of this combination and their impact on cognition and behavior. Research from our laboratories indicates that an established rodent animal model of alcoholism can be extended to investigate the acute and chronic effects of caffeinated ethanol.

The combined effects of alcohol, caffeine, and expectancies on subjective experience, impulsivity, and risk-taking

Caffeinated alcoholic beverage (CAB) consumption is a rapidly growing phenomenon among young adults and is associated with a variety of health-risk behaviors. The current study examined whether either caffeinated alcohol or the expectation of receiving caffeinated alcohol altered affective, cognitive, and behavioral outcomes hypothesized to contribute to risk behavior. Young adult social drinkers (N = 146) participated in a single session where they received alcohol (peak Breath Alcohol Content = .088 g/dL, SD = .019; equivalent to about four standard drinks) and were randomly assigned to one of four further conditions: 1) no caffeine, no caffeine expectancy, 2) caffeine and caffeine expectancy, 3) no caffeine but caffeine expectancy, 4) caffeine but no caffeine expectancy. Participants' habitual CAB consumption was positively correlated with measures of impulsivity and risky behavior, independently of study drugs. Administration of caffeine (mean dose = 220 mg, SD = 38; equivalent to about 2.75 Red Bulls) in the study reduced subjective ratings of intoxication and reversed the decrease in desire to continue drinking, regardless of expectancy. Caffeine also reduced the effect of alcohol on inhibitory reaction time (RT) (faster incorrect responses). Participants not expecting caffeine were less attentive after alcohol, whereas participants expecting caffeine were not, regardless of caffeine administration. Alcohol decreased response accuracy in all participants except those who both expected and received caffeine. Findings suggest that CABs may elevate risk for continued drinking by reducing perceived intoxication, and by maintaining the desire to continue drinking. Simply expecting to consume caffeine may reduce the effects of alcohol on inattention, and either expecting or consuming caffeine may protect against other alcohol-related performance decrements. Caffeine, when combined with alcohol, has both beneficial and detrimental effects on mechanisms known to contribute to risky behavior.