Journal of Caffeine Research

Background: When caffeine is added to beverages, it increases beverage liking and the relative reinforcing value (RRV) of these beverages after repeated exposure. The purpose of this study was to test the hypothesis that a single acute exposure to caffeine increases liking and motivation to consume sugar-sweetened beverages (SSBs) relative to placebo. Methods: Participants were children ages 8-9 years ( n  = 36) and adolescents ages 15-17 years ( n  = 41) with an approximately equal number of boys and girls...

Background: This study was conducted to compare the pharmacokinetics of caffeine delivered using caffeinated chewing gum to that delivered using a marketed caffeinated beverage (instant coffee) in 16 healthy adult volunteers. Materials and Methods: This was a controlled open-label, randomized, two-period crossover study. Caffeinated chewing gum and a serving of instant coffee, each containing ∼50 mg caffeine, were administered with blood samples collected before and up to 24 hours after administration starts...

Background: Energy drink consumption and sleep problems are both associated with alcohol use among adolescents. In addition, caffeine consumption (including energy drinks) is associated with sleep problems. However, information about how these three constructs may interact is limited. The goal of this study was to examine potential interactions between energy drink consumption and sleep problems in the concurrent prediction of alcohol use among young adolescents. Coffee and soda consumption were also examined for comparison...

Background: Apnea of prematurity often occurs during and following caffeine therapy. We hypothesized that number of apnea events would be impacted by adjustments in caffeine therapy. Materials and Methods: An automated algorithm was used in all infants ≤32 weeks gestation admitted to a level IV Neonatal Intensive Care Unit from 2009 to 2014 to analyze chest impedance, electrocardiogram, and oxygen saturation data around the time of serum caffeine levels, caffeine boluses while on maintenance therapy, and caffeine discontinuation...

Objective: Theacrine, a methylurate class purine alkaloid, triggers diverse pharmacologic responses, including psychostimulatory activity by modulation of adenosinergic and dopaminergic pathways. In a double-blind, placebo-controlled study, theacrine increased energy, concentration, and mood, while reducing fatigue. Because caffeine, a methylxanthine purine alkaloid, is frequently coadministered with theacrine, we sought to determine if a pharmacokinetic and/or pharmacodynamic interaction existed between theacrine and caffeine...

Many people avidly consume foods and drinks containing caffeine, despite its bitter taste. Here, we review what is known about caffeine as a bitter taste stimulus. Topics include caffeine's action on the canonical bitter taste receptor pathway and caffeine's action on noncanonical receptor-dependent and -independent pathways in taste cells. Two conclusions are that (1) caffeine is a poor prototypical bitter taste stimulus because it acts on bitter taste receptor-independent pathways, and (2) caffeinated products most likely stimulate "taste" receptors in nongustatory cells...

Background: Medical residencies are highly demanding and stressful and have been associated with mental and emotional problems. Studies that evaluated this relationship in Italian psychiatry residents are scarce. In this study, we examined sleep quality and its association with perceived stress and caffeinated beverages consumption in Italian psychiatry residents. Methods: Seventy-two PGY1-5 psychiatry residents at two University Hospitals in Italy were asked to complete an anonymous questionnaire. The Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were used to determine the sleep quality and the level of daytime sleepiness (EDS)...

Background: The purpose of this study was to determine energy drink (ED) consumption patterns among Hispanic college students. We measured the prevalence and frequency of ED consumption according to gender, degree programs, and specific university-related and social situations. In addition, we assessed the frequency of consumption of EDs mixed with alcoholic beverages. Methods: A total of 508 college students from the University of Puerto Rico, the largest Hispanic institution of higher education statewide, completed an online questionnaire...

Background: The DSM-5 proposes caffeine use disorder (CUD) as a condition for further study. The objective of this study was to report on the prevalence of CUD and rates of endorsement for each substance use disorder (SUD) criterion in relation to caffeine compared to alcohol and marijuana in a sample of adolescents presenting for medical care in the primary, adolescent, and substance use clinics at an academic medical center. Methods: A convenience sample of patients ( N  = 213; 66.7% female) aged 12-17 presenting for medical care completed the Composite Diagnostic Interview-Substance Abuse Module questionnaire, with questions regarding use of caffeine, alcohol, and marijuana...

Background: Although evidence suggests that methylxanthines may lower the seizure threshold, the effect of high-dose caffeine on seizure burden in preterm infants is not known. This study reports a secondary post hoc analysis of a randomized controlled trial of early high-dose caffeine citrate therapy in preterm infants, evaluating the effect of caffeine on the seizure burden using amplitude-integrated electroencephalography (aEEG). Methods: Seventy-four preterm infants (≤30 weeks gestation) were randomized to receive high-dose ( n  = 37, 80 mg/kg over 36 hours) or standard-dose ( n  = 37, 30 mg/kg over 36 hours) caffeine citrate over the first 36 hours followed by standard maintenance therapy...

Objective: The present study investigates risk behaviors, sleep habits, and mental health factors associated with caffeinated beverage use in young adults. Materials and Methods: Students from a midsize private university (n = 159) completed a 15-minute anonymous questionnaire, including questions on risk behaviors, sleep habits, alcohol, and caffeine consumption. We compared behaviors between the top ∼15% ("high end") of energy drink users (≥3/month) and coffee users (≥16/month) to those with less frequent or no caffeine consumption...

Background: Little is known about possible links between energy drink use and psychopathology among youth. This study examined cross-sectional and longitudinal associations between energy drink consumption and psychopathology among early adolescents. In addition, associations between psychopathology and coffee consumption were examined to assess whether findings were specific to energy drinks or also applied to another commonly used caffeinated beverage. Methods: One hundred forty-four youth who participated in the Camden Youth Development Study (72 males; mean age 11...

Background: Concerns have been expressed regarding the potential for caffeinated energy drinks to negatively affect mental health, and particularly so in young consumers at whom they are often targeted. The products are frequently marketed with declarations of increasing mental and physical energy, providing a short-term boost to mood and performance. Although a certain amount of evidence has accumulated to substantiate some of these claims, the chronic effects of energy drinks on mental health also need to be addressed...

Background: Energy drink use is associated with increased risk behavior among adolescents and college students. This study examined this relationship in a nationwide sample of young adults and also examined relations between energy drink use and delay discounting. Methods: Participants were 874 U.S. adults 18-28 years of age with past 30-day consumption of caffeine and alcohol. Participants completed an online survey of energy drink use, drug use, sexual activity, alcohol misuse (alcohol use disorders identification test [AUDIT]), sensation seeking (four-item Brief Sensation Seeking Scale [BSSS-4]), and delay discounting of monetary rewards and condom use...

Purpose: Pediatric caffeine use has become increasingly prevalent. The American Academy of Pediatrics discourages caffeine use by children and adolescents due to its adverse impact on sleep and blood pressure. The objective of this study was to measure prevalence of physical and emotional symptoms related to caffeine consumption among adolescents receiving primary care. Methods: A convenience sample of patients (N = 179; 73% female) aged 12-17 presenting for routine primary care completed the Composite International Diagnostic Interview Substance Abuse Module questionnaire, which included questions regarding use of caffeine...

Introduction: We present a review of the methodological aspects of caffeine research within animal tests of escape and avoidance behavior in the presence of aversive stimuli. Method: We highlight species, methods of caffeine administration, dosage, dependent measures, and research designs commonly used in this research. Results: Typical subjects were rodents and zebrafish, with species-specific vehicles of caffeine administration and dependent measures. Behavioral tests for escape and avoidance as a function of caffeine consumption were conceptually similar across species, although the arrangement of measures was necessarily adapted to the physiological contingencies of the different species...

Background: Our previous work has shown that there are sex differences in subjective responses to acute caffeine administration in adolescents. The purpose of this study was to determine if these sex differences are dependent on pubertal development. Materials and Methods: We examined subjective responses before and after administration of 0, 1, and 2 mg/kg of caffeine in pre- and postpubertal boys and girls (n = 112). In addition, we examined differences in subjective responses to acute caffeine in both the luteal and follicular phases of the menstrual cycle in postpubertal girls...

Background: Recent research has linked caffeine consumption with a lower risk for depression and cognitive decline. However, no studies have examined the relationship in an African American compared to a white, socioeconomically diverse representative urban sample. Methods: Data from a cross-sectional study were used to determine the associations of caffeine use with depressive symptomatology and cognition in a sample of 1,724 participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study...

Studies of gene-environment interactions may help us to understand the disease mechanisms of common and complex diseases such as Parkinson's disease (PD). Sporadic PD, the common form of PD, is thought to be a multifactorial disorder caused by combinations of multiple genetic factors and environmental or life-style exposures. Since one of the most extensively studied life-style factors in PD is coffee/caffeine intake, here, the studies of genetic polymorphisms with life-style interactions of sporadic PD are reviewed, focusing on coffee/caffeine intake...

Background: Caffeine is the most widely consumed psychoactive substance in the world, even during pregnancy. Its stimulatory effects are mainly due to antagonism of adenosine actions by blocking adenosine A1 and A2A receptors. Previous studies have shown that caffeine can cross the placenta and therefore modulate these receptors not only in the fetal brain but also in the heart. Methods: In the present work, the effect of caffeine chronically consumed during pregnancy on A1 and A2A receptors in Wistar rat heart, from both mothers and their fetuses, were studied using radioligand binding, Western-blotting, and adenylyl cyclase activity assays, as well as reverse transcription polymerase chain reaction...