Caffeine effects on learning, performance, and anxiety in normal school-age children

ACE gene polymorphisms (rs4340) II and DI are more responsive to the ergogenic effect of caffeine than DD on aerobic power, heart rate, and perceived exertion in a homogeneous Brazilian group of adolescent athletes

The purpose of this study was to verify the association between angiotensin-converting enzyme (ACE) genotypes DD, DI, and II and caffeine (CAF) ingestion on endurance performance, heart rate, ratio of perceived exertion (RPE), and habitual caffeine intake (HCI) of adolescent athletes. Seventy-four male adolescent athletes (age: DD=16±1.7; DI=16±2.0; II=15±1.7 years) ingested CAF (6 mg/kg) or placebo (PLA) one hour before performing the Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) test. No difference was found among groups for HCI. However, CAF increased the maximal distance covered and VO2max in DI and II genotype carriers compared to PLA (DD: Δ=31 m and 0.3 mL·kg-1·min-1; DI: Δ=286 m and 1.1 mL·kg-1·min-1; II: Δ=160 m and 1.4 mL·kg-1·min-1). Heart rate of DI and II genotype carriers increased with CAF compared to PLA, while RPE was higher in the II and lower in the DD genotypes. The correlations between HCI and maximal distance covered or VO2max were significant in the II genotype carriers with CAF. CAF increased endurance capacity, heart rate, and RPE in adolescent athletes with allele I, while endurance performance and aerobic power had a positive correlation to HCI in the II genotype group. These findings suggested that DD genotype were less responsive to CAF and that genetic variations should be taken into account when using CAF supplementation to enhance exercise performance.

Proposing a "Brain Health Checkup (BHC)" as a Global Potential "Standard of Care" to Overcome Reward Dysregulation in Primary Care Medicine: Coupling Genetic Risk Testing and Induction of "Dopamine Homeostasis"

In 2021, over 100,000 people died prematurely from opioid overdoses. Neuropsychiatric and cognitive impairments are underreported comorbidities of reward dysregulation due to genetic antecedents and epigenetic insults. Recent genome-wide association studies involving millions of subjects revealed frequent comorbidity with substance use disorder (SUD) in a sizeable meta-analysis of depression. It found significant associations with the expression of NEGR1 in the hypothalamus and DRD2 in the nucleus accumbens, among others. However, despite the rise in SUD and neuropsychiatric illness, there are currently no standard objective brain assessments being performed on a routine basis. The rationale for encouraging a standard objective Brain Health Check (BHC) is to have extensive data available to treat clinical syndromes in psychiatric patients. The BHC would consist of a group of reliable, accurate, cost-effective, objective assessments involving the following domains: Memory, Attention, Neuropsychiatry, and Neurological Imaging. Utilizing primarily PUBMED, over 36 years of virtually all the computerized and written-based assessments of Memory, Attention, Psychiatric, and Neurological imaging were reviewed, and the following assessments are recommended for use in the BHC: Central Nervous System Vital Signs (Memory), Test of Variables of Attention (Attention), Millon Clinical Multiaxial Inventory III (Neuropsychiatric), and Quantitative Electroencephalogram/P300/Evoked Potential (Neurological Imaging). Finally, we suggest continuing research into incorporating a new standard BHC coupled with qEEG/P300/Evoked Potentials and genetically guided precision induction of "dopamine homeostasis" to diagnose and treat reward dysregulation to prevent the consequences of dopamine dysregulation from being epigenetically passed on to generations of our children.

Clinical Evidence of the Benefits of Phytonutrients in Human Healthcare

Phytonutrients comprise many different chemicals, including carotenoids, indoles, glucosinolates, organosulfur compounds, phytosterols, polyphenols, and saponins. This review focuses on the human healthcare benefits of seven phytochemical families and highlights the significant potential contribution of phytonutrients in the prevention and management of pathologies and symptoms in the field of family health. The structure and function of these phytochemical families and their dietary sources are presented, along with an overview of their potential activities across different health and therapeutic targets. This evaluation has enabled complementary effects of the different families of phytonutrients in the same area of health to be recognized.

Experimental study of pre- and postnatal caffeine exposure and its observable effects on selected neurotransmitters and behavioural attributes at puberty : Caffeine exposure and its observable effects on selected neurotranmitters and behaviour

Caffeine is globally consumed as a stimulant in beverages. It is also ingested in purified forms as power and tablets. Concerns have been raised about the potential consequences of intrauterine and early life caffeine exposure on brain health. This study modeled caffeine exposure during pregnancy and early postanal life until puberty, and the potential consequences. Caffeine powder was dissolved in distilled water. Thirty-two (n = 32) pregnant mice (Mus musculus) (dams) were divided into four groups- A, B, C and D. Group A animals served as a control, receiving placebo. Caffeine doses in mg/kg body weight were administered as follows: Group B, 10 mg/kg; Group C, 50 mg/kg; Group D, 120 mg/kg. Prenatal caffeine exposure [phase I] lasted throughout pregnancy. Half the number of offspring (pups) were sacrificed at birth; the rest were recruited into phase II and the experiment continued till day 35, marking puberty. Brain samples were processed following sacrifice. γ-aminobutyric acid (GABA), acetylcholine (ACh), and serotonin (5Ht) neurotransmitters were assayed in homogenates to evaluate functional neurochemistry. Anxiety and memory as neurobehavioural attributes were observed using the elevated plus and Barnes' mazes respectively. Continuous caffeine exposure produced positive effects on short and long-term memory parameters; the pattern interestingly was irregular and appeared more effective with the lowest experimental dose. Anxiety test results showed no attributable significant aberrations. Caffeine exposure persistently altered the neurochemistry of selected neurotransmitters including ACh and 5Ht, including when exposure lasted only during pregnancy. ACh significantly increased in group B^C+ to 0.3475μgg-¹ relative to control's 0.2508μgg-¹; pre-and continuous postnatal exposure in Group B increased 5Ht to 0.2203 μgg-¹ and 0.2213 μgg-¹ respectively relative to control's 0.1863 μgg-¹. From the current investigation, caffeine exposure in pregnancy had persistent effects on brain functional attributes including neurotransmitters activities, memory and anxiety. Caffeine in moderate doses affected memory positively but produced negative effects at the higher dosage including increased anxiety tendencies.

Calories, Caffeine and the Onset of Obesity in Young Children

OBJECTIVE

High calorie foods and beverages, which often contain caffeine, contribute to child overweight/obesity. We evaluated the results of an educational intervention to promote healthy growth in very young children. Secondarily, we used detailed diet data to explore the association of nutrient intake with the early development of overweight and obesity.

METHODS

Mothers were obese Latina women, enrolled prenatally, and their infants. Specially trained community health workers provided breastfeeding support and nutrition education during 10 home visits, birth to 24 months. At follow-up, age 18 to 36 months, we measured growth and completed detailed diet recalls (1-7 recall days/child).

RESULTS

Of 174 infants randomized, 106 children were followed for 24 to 36 months. The educational intervention did not prevent overweight/obesity. Forty-two percent of children became overweight or obese. Fifty-eight percent of children consumed caffeine on at least 1 recall day. Mean intake was 0.48 mg/kg/day. Caffeine correlated with higher consumption of calories, and added sugar and decreased intake of protein, fiber and dairy. Compared with days without caffeine, on days when caffeine was consumed, children ingested 121 more calories and 3.8 gm less protein. Children frequently consumed less than the recommended daily intake of key nutrients such as fiber, vegetables, whole fruit, and vitamins.

CONCLUSIONS

Caffeine was a marker for increased intake of calories and decreased intake of key nutrients. When discussing dietary intake in early childhood, practitioners should screen for nutrient deficiency in young children and recommend limiting the intake of caffeinated foods and beverages.

Caffeine Consumption through Coffee: Content in the Beverage, Metabolism, Health Benefits and Risks

Caffeine (1,3,7-trimethylxanthine) is the most consumed psychoactive substance in the world, acting by means of antagonism to adenosine receptors, mainly A1 and A2A. Coffee is the main natural source of the alkaloid which is quite soluble and well extracted during the brew’s preparation. After consumption, caffeine is almost completely absorbed and extensively metabolized in the liver by phase I (cytochrome P450) enzymes, mainly CYP1A2, which appears to be polymorphically distributed in human populations. Paraxanthine is the major caffeine metabolite in plasma, while methylated xanthines and methyluric acids are the main metabolites excreted in urine. In addition to stimulating the central nervous system, caffeine exerts positive effects in the body, often in association with other substances, contributing to prevention of several chronic diseases. The potential adverse effects of caffeine have also been extensively studied in animal species and in humans. These aspects will be approached in the present review.

Review: Trends, Safety, and Recommendations for Caffeine Use in Children and Adolescents

OBJECTIVE

Caffeine use is common in children and adolescents, but the recommendations for safe consumption are based on decades-old data collected exclusively in adults. Increased availability of caffeine-containing products and a concerted marketing effort aimed at children and adolescents, has increased interest in understanding the physiological, behavioral, and psychological effects of caffeine within this population. This manuscript provides a review of the literature concerning trends and safety of ingested caffeine in children and adolescents.

METHOD

A search of the National Library of Medicine database was conducted using the terms caffeine, children, adolescents, and safety, in addition to tailored searches on specific topics using combinations of search terms such as energy drinks, cardiovascular, mood, cognitive, mental health, sleep, and regulations.

RESULTS

The majority of the literature reviewed here suggests that typical, moderate caffeine consumption in children and adolescents is relatively safe, but that higher doses of caffeine consumption (>400 mg) can cause physiological, psychological, and behavioral harm, in particular in subgroups of children, such as those with psychiatric or cardiac conditions. More attention is being paid to the potential adverse effects of both acute and chronic caffeine use, and additional regulations surrounding the sale and marketing of highly caffeinated beverages are now being considered.

CONCLUSION

More research is needed to fill in gaps in our knowledge, including understanding the relationship between caffeine use and initiation of other substances, such as cigarettes, alcohol, or marijuana, identifying individuals at risk for caffeine toxicity, and developing harm-reduction strategies.

Methylxanthine Content in Commonly Consumed Foods in Spain and Determination of Its Intake during Consumption

Methylxanthines present psychostimulant effects. These compounds have low toxicity and their consumption at moderate levels presents some beneficial health effects, whereas some significant risk appears at high levels. Samples of common types of methylxanthine-containing beverages and foods consumed in Spain were analyzed to determine their content. Caffeine was the methylxanthine that was most found in the samples investigated. Instant coffees gave the highest caffeine percentage (18–44 mg·g⁻¹). Green and scented teas were found to have a caffeine dry-weight content (8–26 mg·g⁻¹) equivalent to ground coffees (13–23 mg·g⁻¹), but black and pu-erh teas (18–30 mg·g⁻¹) had a higher caffeine content. The evaluation of the most conventional methods for preparing espresso coffees showed that an espresso contains between 88–116 mg of caffeine. In the case of tea beverages, the amount of caffeine present was 2–3 times smaller than in espresso coffees. Energy drinks showed a similar caffeine content (80–106 mg) as espresso coffees. Chocolates had the lowest caffeine content. It has been found that none of the foods evaluated reach the recommended daily intake limit of 400 mg of caffeine with a single dose. This limit can be reached with 4–5 doses in the case of coffees and energy drinks. In the case of chocolates, the methylxanthine compound detected at large levels was theobromine, with amounts ranging from 4 to 10 mg·g⁻¹ for dark chocolates.

Caffeine for apnea of prematurity: Effects on the developing brain

Caffeine is a methylxanthine that is widely used to treat apnea of prematurity (AOP). In preterm infants, caffeine reduces the duration of respiratory support, improves survival rates and lowers the incidence of cerebral palsy and cognitive delay. There is, however, little evidence relating to the immediate and long-term effects of caffeine on brain development, especially at the cellular and molecular levels. Experimental data are conflicting, with studies showing that caffeine can have either adverse or benefical effects in the developing brain. The aim of this article is to review current understanding of how caffeine ameliorates AOP, the cellular and molecular mechanisms by which caffeine exerts its effects and the effects of caffeine on brain development. A better knowledge of the effects of caffeine on the developing brain at the cellular and/or molecular level is essential in order to understand the basis for the impact of caffeine on postnatal outcome. The studies reviewed here suggest that while caffeine has respiratory benefits for preterm infants, it may have adverse molecular and cellular effects on the developing brain; indeed a majority of experimental studies suggest that regardless of dose or duration of administration, caffeine leads to detrimental changes within the developing brain. Thus there is an urgent need to assess the impact of caffeine, at a range of doses, on the structure and function of the developing brain in preclinical studies, particularly using clinically relevant animal models. Future studies should focus on determining the maximal dose of caffeine that is safe for the preterm brain.

Energy Drink and Coffee Consumption and Psychopathology Symptoms Among Early Adolescents: Cross-Sectional and Longitudinal Associations

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 11.9 at wave 1; 65% Hispanic, 30% African American) were assessed using self-report measures of frequency of energy drink and coffee consumption and depression, anxiety, conduct disorder (CD) symptoms, and teacher reports of attention-deficit hyperactivity disorder (ADHD). Youth (92%) were reassessed 16 months later. Results: Concurrently, energy drink and coffee consumption were associated with similar psychopathology symptoms; when the other beverage was adjusted for, energy drinks remained associated with CD and coffee remained associated with panic anxiety. Initial energy drink consumption predicted increasing ADHD and CD over time, though the association with CD dropped to a trend level of significance when coffee was adjusted for. Initial levels of hyperactive ADHD predicted increasing coffee consumption over time; this association remained when energy drinks were controlled. Social anxiety was associated with less increase in energy drink consumption over time, controlling for coffee. Conclusion: Energy drink and coffee consumption among early adolescents are concurrently associated with similar psychopathology symptoms. Longitudinally, the associations between these beverages and psychopathology differ, indicating that these substances have differing implications for development over time.

The Relationship of Caffeine Intake with Depression, Anxiety, Stress, and Sleep in Korean Adolescents

BACKGROUND

In various studies in adults, caffeine may increase wakefulness and relieve pain, but caffeine overdose can cause many adverse serious effects on health. Caffeine intake has recently been increasing in adolescents. In spite of importance of caffeine effects on Korean adolescents, there are lack of scientific and systematic studies. The purpose of our study was to identify the relationship between caffeine consumption and effects on adolescents.

METHODS

We performed study on 234 middle school students at one middle school in Daegu using a self-report questionnaire. We divided students to quartiles according to amount of caffeine intake. We used Beck Depression Inventory (BDI) to evaluate the degree of depression and Beck Anxiety Inventory (BAI) to evaluate the degree of anxiety. We also used Insomnia Severity Scale (ISI) to evaluate the degree of insomnia and Global Assessment of Recent Stress (GARS) to evaluate the stress in students. We used logistic regression analysis to identify the relationship between caffeine consumption and effects.

RESULTS

Higher caffeine intake was associated with higher weight, height, lower academic achievement, and higher score in BDI, BAI, ISI, and GARS (P for trend <0.005). Higher caffeine intake quartile was associated with greater odds of having significant depression (BDI ≥10, P for trend=0.011), and insomnia (ISI ≥8, P for trend=0.015) after adjustment for factors that can affect the psychological status.

CONCLUSION

We found that caffeine intake is associated weight, height, academic achievement, and higher score in BDI, BAI, ISI, and GARS. Caffeine intake was positively associated with the severity of depression and the severity of insomnia among adolescents in Korean.

Adolescent Attitudes and Beliefs Regarding Caffeine and the Consumption of Caffeinated Beverages

OBJECTIVES

To explore adolescents' attitudes and beliefs toward the consumption of caffeinated beverages and factors influencing their caffeinated beverage choice and consumption patterns.

DESIGN

Twenty focus groups were conducted with grades 9 to 12 secondary school students.

SETTING

Two secondary schools in London, Ontario, Canada.

PARTICIPANTS

This study included 166 adolescents, 42% of whom were male and 72% of whom were in grades 9 and 10.

PHENOMENON OF INTEREST

Adolescent views regarding caffeine and caffeinated beverages.

ANALYSIS

Three researchers independently conducted inductive content analysis on the data using the principles of the immersion-crystallization method.

RESULTS

Awareness levels regarding types of caffeinated beverages and their negative health effects were high in adolescents whereas awareness of other aspects of caffeine itself and recommended consumption levels were low. Adolescents also identified reasons for caffeine use, including providing energy, taste, accessibility, and image enhancement. Influences for caffeine use most noted by participants included parental role modeling, media and advertising, and social norms.

CONCLUSIONS AND IMPLICATIONS

Further education is needed to correct the misconceptions adolescents have regarding certain aspects of caffeine. By gaining a deeper understanding of adolescents' caffeine use, effective educational strategies may be developed to reduce its use and mitigate potential harms.

Caffeine's influence on object recognition and working-memory in prepubertal mice and its modulation by gender

OBJECTIVE

This study investigated the effects of intraperitoneal injection of caffeine on Y-maze working-memory and novel object recognition (NOR) in prepubertal mice.

METHODOLOGY

Y-maze spontaneous alternation and a novel object recognition test (consisting of acclimation, acquisition and test phases) were performed. Mice received a single dose of caffeine (10, 20, 40, 80 and 120mgkg(-1) i.p.) or vehicle, 30min before Y-maze exploration. For the NOR test, caffeine was given 30min before training and another dose 30min before test phase.

RESULTS

NOR time (acquisition phase) increased significantly in males at all doses of caffeine and decreased in females at 10, 20 and 40mg/kg compared to vehicle; during the test phase, novel object exploration time decreased significantly in males and increased in females at 10 and 20mg/kg only to decrease again at 120mg/kg. Recognition index decreased in males and increased in females while, males showed poor discrimination between novel and familiar objects compared to vehicle; while females showed increased discrimination between novel and familiar object at 10, 20,40 and 80mg/kg and a decrease at 120mg/kg. Y-maze spontaneous alternation improved significantly in males at 10 and 40mg/kg and decreased at 20 and 120mg/kg in females.

CONCLUSION

The findings suggest that acute caffeine injection improves non-spatial memory retention in female mice but not in males; spatial working-memory is however improved in males but not in females.

Effect of energy drink and caffeinated beverage consumption on sleep, mood, and performance in children and adolescents

The increasing availability of highly caffeinated beverages, including energy drinks, in the United States has resulted in a rise in consumption by children and adolescents. In addition, there is mounting evidence that these products are often consumed by youth for their perceived fatigue-mitigating and mood- or performance-enhancing effects. Although such perceptions by children and adolescents about the potential consequences of caffeine consumption are highly likely to influence decision making regarding the use of such products, there is still a relative paucity of studies that focus on the effect of caffeinated beverages on sleep, mood, and performance in the pediatric population. This review summarizes the following aspects of this topic, as derived from the information currently available: 1) the perception, among youth, of caffeine's risks and benefits and the sources of information about caffeine, particularly with regard to sleep, mood, and performance; 2) the bidirectional effect of caffeine on sleep in children and adolescents and the association of caffeine with other sleep-related practices, and 3) the evidence that supports caffeine as a performance and mood enhancer as well as a countermeasure to sleepiness in the pediatric population. Finally, gaps in knowledge are identified, and a direction for future research is outlined.

Caffeine intake in children in the United States and 10-y trends: 2001-2010

BACKGROUND

Because of the increasing concern of the potential adverse effects of caffeine intake in children, recent estimates of caffeine consumption in a representative sample of children are needed.

OBJECTIVES

We provide estimates of caffeine intake in children in absolute amounts (mg) and in relation to body weight (mg/kg) to examine the association of caffeine consumption with sociodemographic factors and describe trends in caffeine intake in children in the United States.

DESIGN

We analyzed caffeine intake in 3280 children aged 2-19 y who participated in a 24-h dietary recall as part of the NHANES, which is a nationally representative survey of the US population with a cross-sectional design, in 2009-2010. Trends over time between 2001 and 2010 were examined in 2-19-y-old children (n = 18,530). Analyses were conducted for all children and repeated for caffeine consumers.

RESULTS

In 2009-2010, 71% of US children consumed caffeine on a given day. Median caffeine intakes for 2-5-, 6-11-, and 12-19-y olds were 1.3, 4.5, and 13.6 mg, respectively, and 4.7, 9.1, and 40.6 mg, respectively, in caffeine consumers. Non-Hispanic black children had lower caffeine intake than that of non-Hispanic white counterparts. Caffeine intake correlated positively with age; this association was independent of body weight. On a given day, 10% of 12-19-y-olds exceeded the suggested maximum caffeine intake of 2.5 mg/kg by Health Canada. A significant linear trend of decline in caffeine intake (in mg or mg/kg) was noted overall for children aged 2-19 y during 2001-2010. Specifically, caffeine intake declined by 3.0 and 4.6 mg in 2-5- and 6-11-y-old caffeine consumers, respectively; no change was noted in 12-19-y-olds.

CONCLUSION

A majority of US children including preschoolers consumed caffeine. Caffeine intake was highest in 12-19-y-olds and remained stable over the 10-y study period in this age group.

The suitability of caffeinated drinks for children: a systematic review of randomised controlled trials, observational studies and expert panel guidelines

BACKGROUND

The increased availability of caffeinated drinks raises questions about the level of caffeine that is appropriate for children, as well as the benefits and risks associated with their consumption.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, this systematic review evaluates evidence from randomised controlled trials investigating the effects of caffeine on cognition, behaviour, mood and exercise performance in children. Observational studies and expert panel guidelines are also discussed.

RESULTS

One hundred and nine studies were found, with 11 randomised controlled trials and 13 observational studies meeting the criteria. High caffeine intakes (e.g. >5 mg kg(-1) body weight day(-1)) were associated with an increased risk of anxiety and withdrawal symptoms. However, smaller amounts were not linked with such effects and may benefit cognitive function and sports performance based on adult studies. The evidence suggests that children and adolescents should limit daily caffeine consumption to 2.5 mg kg(-1) body weight day(-1), equating to one or two cups of tea or one small cup of coffee. Lower contributors of caffeine, such as tea, may be more appropriate for children because they contribute to daily fluid intakes and provide flavonoids. By contrast, caffeinated soft drinks may be less suitable options for children as a result of their acidity, higher caffeine content, presence of added sugar (in some cases) and absence of bioactive compounds.

CONCLUSIONS

More studies are needed to determine the intakes that represent a risk and whether there may be benefits for alertness and sports performance with moderate intakes of caffeine.

Maternal caffeine consumption and infant nighttime waking: prospective cohort study

OBJECTIVE

Coffee and other caffeinated beverages are commonly consumed in pregnancy. In adults, caffeine may interfere with sleep onset and have a dose-response effect similar to those seen during insomnia. In infancy, nighttime waking is a common event. With this study, we aimed to investigate if maternal caffeine consumption during pregnancy and lactation leads to frequent nocturnal awakening among infants at 3 months of age.

METHODS

All children born in the city of Pelotas, Brazil, during 2004 were enrolled on a cohort study. Mothers were interviewed at delivery and after 3 months to obtain information on caffeine drinking consumption, sociodemographic, reproductive, and behavioral characteristics. Infant sleeping pattern in the previous 15 days was obtained from a subsample. Night waking was defined as an episode of infant arousal that woke the parents during nighttime. Multivariable analysis was performed by using Poisson regression.

RESULTS

The subsample included 885 of the 4231 infants born in 2004. All but 1 mother consumed caffeine in pregnancy. Nearly 20% were heavy consumers (≥300 mg/day) during pregnancy and 14.3% at 3 months postpartum. Prevalence of frequent nighttime awakeners (>3 episodes per night) was 13.8% (95% confidence interval: 11.5%-16.0%). The highest prevalence ratio was observed among breastfed infants from mothers consuming ≥300 mg/day during the whole pregnancy and in the postpartum period (1.65; 95% confidence interval: 0.86-3.17) but at a nonsignificant level.

CONCLUSIONS

Caffeine consumption during pregnancy and by nursing mothers seems not to have consequences on sleep of infants at the age of 3 months.

Potential link between caffeine consumption and pediatric depression: A case-control study

BACKGROUND

Early-onset depressive disorders can have severe consequences both from developmental and functional aspects. The etiology of depressive disorders is complex and multi-factorial, with an intricate interaction among environmental factors and genetic predisposition. While data from studies on adults suggest that caffeine is fairly safe, effects of caffeine in children, who are in period of rapid brain development, are currently unknown. Furthermore, systematic research addressing the relationship between depressive symptoms in children and caffeine consumption is lacking.The present study examined the effects of caffeine consumption on depressed mood in children with depression and non-depressed participants.

METHODS

Children and adolescents (n = 51) already enrolled in an ongoing longitudinal study, aged 9-12 years, were assessed for depressive symptoms with the Children Depressive Inventory (CDI). Psychopathological symptoms were assessed with the Child Behavioral Checklist (CBCL) and eating habits were assessed with the Nutrition-Behavior Inventory (NBI) 1. The children were compared to control children without psychopathology attending public schools in a Southern Brazilian city.

RESULTS

Participants with CDI scores ≥ 15 (mean = 19; S.D. = 4) also had high NBI scores (mean = 52; S.D. = 19, p < 0.001) suggestive of a relationship between depressive symptoms and environmental factors, in this case nutrition/behavior. Additional linear regression adjusted statistical analysis, considering the factors of consumption of sweets and caffeine individually, showed that caffeine, but not sweets, was associated with depressive symptoms.

CONCLUSIONS

These findings indicate that depressed children consume more caffeinated drinks than non-depressed children. Nonetheless while a strong association between depressive symptoms and caffeine consumption among children was found, further research should investigate whether or not this association is due to a cause and effect relationship.

Sports drinks and energy drinks for children and adolescents: are they appropriate?

Sports and energy drinks are being marketed to children and adolescents for a wide variety of inappropriate uses. Sports drinks and energy drinks are significantly different products, and the terms should not be used interchangeably. The primary objectives of this clinical report are to define the ingredients of sports and energy drinks, categorize the similarities and differences between the products, and discuss misuses and abuses. Secondary objectives are to encourage screening during annual physical examinations for sports and energy drink use, to understand the reasons why youth consumption is widespread, and to improve education aimed at decreasing or eliminating the inappropriate use of these beverages by children and adolescents. Rigorous review and analysis of the literature reveal that caffeine and other stimulant substances contained in energy drinks have no place in the diet of children and adolescents. Furthermore, frequent or excessive intake of caloric sports drinks can substantially increase the risk for overweight or obesity in children and adolescents. Discussion regarding the appropriate use of sports drinks in the youth athlete who participates regularly in endurance or high-intensity sports and vigorous physical activity is beyond the scope of this report.

Mountain Dew or mountain don't?: a pilot investigation of caffeine use parameters and relations to depression and anxiety symptoms in 5th- and 10th-grade students

BACKGROUND

Caffeine, the only licit psychoactive drug available to minors, may have a harmful impact on students' health and adjustment, yet little is known about its use or effects on students, especially from a developmental perspective. Caffeine use in 5th- and 10th-grade students was examined in a cross-sectional design, and relations and potential mediators of caffeine use to depression and anxiety symptoms were investigated.

METHODS

Children (n = 135) and adolescents (n = 79) completed a measure of naturalistic use of caffeinated and noncaffeinated beverages. Furthermore, daily availability, perceived benefits, and stimulating, psychological, and withdrawal effects of caffeinated and noncaffeinated beverages were assessed. Measures of depression and anxiety were also administered.

RESULTS

Fifth and 10th graders used caffeine frequently. Depression was positively related to caffeine use for both cohorts, though mediated by caffeine withdrawal effects. Surprisingly, anxiety was unrelated to use. Fifth graders reported less daily access to caffeine, but more psychological and stimulating effects of caffeine than 10th graders.

CONCLUSIONS

Although both children and adolescents experience negative caffeine-related outcomes, intake is seemingly not greatly limited in either cohort. In particular, youth appear vulnerable to increased depressive symptoms with increasing caffeine consumption. Implications for school policy regarding students' caffeine use are discussed.

Caffeine use in children: what we know, what we have left to learn, and why we should worry

Caffeine is a widely used psychoactive substance in both adults and children that is legal, easy to obtain, and socially acceptable to consume. Although once relatively restricted to use among adults, caffeine-containing drinks are now consumed regularly by children. In addition, some caffeine-containing beverages are specifically marketed to children as young as 4 years of age. Unfortunately, our knowledge of the effects of caffeine use on behavior and physiology of children remains understudied and poorly understood. The purpose of this article is to review what is known about caffeine use in children and adolescents, to discuss why children and adolescents may be particularly vulnerable to the negative effects of caffeine, and to propose how caffeine consumption within this population may potentiate the rewarding properties of other substances. The following topics are reviewed: (1) tolerance and addiction to caffeine, (2) sensitization and cross-sensitization to the effects of caffeine, (3) caffeine self-administration and reinforcing value, and (4) conditioning of preferences for caffeine-containing beverages in both adults and children.

Attention-deficit hyperactivity disorder (ADHD): does new research support old concepts?

OBJECTIVE

To examine the evidence for and against the classification of attention-deficit hyperactivity disorder (ADHD) as a valid disease entity, as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV ), criteria.

DATA SOURCES

Sources included but were not limited to published literature on ADHD accessed via PubMed (http://www.ncbi.nlm.nih.gov/PubMed/).

STUDY SELECTION

Peer-reviewed research, review articles, consensus statements, "white papers," and proceedings of professional meetings were used.

DATA EXTRACTION

Focused on evidence base and scientific validity of conclusions.

DATA SYNTHESIS

Evidence for a genetic or neuroanatomic cause of ADHD is insufficient. Experimental work shows that executive function deficits do not explain ADHD. The psychometric properties of widely used ADHD rating scales do not meet standards expected for disease identification.

CONCLUSIONS

ADHD is unlikely to exist as an identifiable disease. Inattention, hyperactivity, and impulsivity are symptoms of many underlying treatable medical, emotional, and psychosocial conditions affecting children.

Influence of caffeine ingestion on perceived mood states, concentration, and arousal levels during a 75-min university lecture

This investigation aimed to assess the effect of a caffeine supplement on perceived mood state, concentration, and arousal during a 75-min university lecture. Methods. This randomized, blind, cross-over design investigation ran over a course of 2 consecutive weeks. During week 1, 10 third-year Human Movement and Exercise Science students were assigned to either a caffeine- or placebo-supplemented group and were subsequently required to attend a 75-min exercise rehabilitation lecture. Seven days later, students were assigned to the opposite supplementation group before attending a second follow-on lecture, equal in duration to that of week 1. At the conclusion of each lecture, students were required to complete a mood perception questionnaire to assess the perceived level of mood state, concentration, and arousal during the lecture. The results showed that after caffeine consumption, students perceived themselves to be significantly more awake, clear minded, energetic, alert, and anxious (P < 0.05). Additionally, students also felt they were better able to concentrate and had a greater level of arousal than when the placebo was consumed (P < 0.05). In conclusion, the results of this investigation show that university students report enhanced perceptual feelings of behavior and mood state when a low dose of caffeine is consumed 60 min prior to a 75-min academic lecture.

Caffeine consumption, sleep, and affect in the natural environments of depressed youth and healthy controls

OBJECTIVE

Sleep problems are a cardinal symptom of depression in children and adolescents and caffeine use is a prevalent and problematic issue in youth; yet little is known about caffeine use and its effects on sleep in youth with depression. We examined caffeine use and its relation to sleep and affect in youth's natural environments.

METHODS

Thirty youth with major depressive disorder (MDD) and 23 control youth reported on caffeine use, sleep, and affect in their natural environment using ecological momentary assessment at baseline and over 8 weeks, while MDD youth received treatment.

RESULTS

Youth with MDD reported more caffeine use and sleep problems relative to healthy youth. Youth with MDD reported more anxiety on days they consumed caffeine. Caffeine use among youth with MDD decreased across treatment, but sleep complaints remained elevated.

CONCLUSIONS

Findings suggest that both sleep quality and caffeine use are altered in pediatric depression; that caffeine use, but not sleep problems, improves with treatment; and that caffeine may exacerbate daily anxiety among youth with depression.

Neonatal caffeine administration causes a permanent increase in the dendritic length of prefrontal cortical neurons of rats

We studied the morphological changes of the dendritic length of the pyramidal neurons of the prefrontal cortex (PFC) induced by the effect of chronic administration of caffeine in the neonatal rat. The caffeine (50 mg/kg, s.c.) was injected from day 1 after birth (P1) to day 12 (P12). The morphology of the pyramidal neurons of layer 3 of the PFC was investigated in these animals at two different ages, before puberty (P35) and after puberty (P70). Before the animals were sacrificed by using overdoses of sodium pentobarbital and being perfused intracardially with 0.9% saline, the locomotor activity in a novel environment was measured. The brains were then removed, processed by the Golgi-Cox stain, and analyzed by the Sholl method. The dendritic morphology clearly showed that the neonatal animals administered caffeine showed an increase in the dendritic length of the pyramidal neurons of the PFC when compared with the control animals at both ages. The present results suggest that neonatal administration of caffeine may in part affect the dendritic morphology of the pyramidal cells of this limbic structure and this effect persists after puberty and may be implicated in several brain processes.

Psychostimulant and other effects of caffeine in 9- to 11-year-old children

BACKGROUND

Recent research on adults suggests that "beneficial" psychostimulant effects of caffeine are found only in the context of caffeine deprivation; that is, caffeine improves psychomotor and cognitive performance in habitual caffeine consumers following caffeine withdrawal. Furthermore, no net benefit is gained because performance is merely restored to "baseline" levels. The effects of caffeine in children is an under-researched area, with only a handful of studies being carried out in the US where children's consumption of caffeine appears to be lower on average than in the UK.

METHOD

Twenty-six children aged between 9 and 11 years completed a double-blind, placebo-controlled study. Habitual caffeine consumers (mean daily caffeine intake = 109 mg) and non/low-consumers (12 mg) were tested on two separate days following overnight caffeine abstinence. On each day measures of cognitive performance (a number search task), and self-rated mood and physical symptoms, including alertness and headache, were taken before and after administration of 50 mg of caffeine, or placebo.

RESULTS

At baseline (before treatment), the habitual consumers showed poorer performance on the cognitive test than did the non/low-consumers, although no significant differences in mood or physical symptoms were found between the two groups. There were significant habit by treatment (caffeine vs. placebo) interactions for accuracy of performance and headache, and a significant main effect of treatment for alertness. Post hoc comparisons showed that caffeine administration improved the consumers' accuracy on the cognitive test (to near the level displayed by the non/low-consumers at baseline), but that it had no significant effect on the non/low-consumers' performance. In the consumers, caffeine prevented an increase in headache that occurred after placebo, and it increased alertness relative to placebo. Again, however, caffeine did not significantly affect levels of headache or alertness in the non/low-consumers.

CONCLUSIONS

These results suggest that, like adults, children probably derive little or no benefit from habitual caffeine intake, although negative symptoms associated with overnight caffeine withdrawal are avoided or rapidly reversed by subsequent caffeine consumption.

What is attention-deficit hyperactivity disorder (ADHD)?

Attention-deficit hyperactivity disorder (ADHD) is described as the most common neurobehavioral condition of childhood. We raise the concern that ADHD is not a disease per se but rather a group of symptoms representing a final common behavioral pathway for a gamut of emotional, psychological, and/or learning problems. Increasing numbers of children, especially boys, are diagnosed with ADHD and treated with stimulant medications according to a simplified approach. Methodical review of the literature, however, raised concerning issues. "Core" ADHD symptoms of inattentiveness, hyperactivity and impulsivity are not unique to ADHD. Rates of "comorbid" psychiatric and learning problems, including depression and anxiety, range from 12 to 60%, with significant symptom overlap with ADHD, difficulties in diagnosis, and evidence-based treatment methods that do not include stimulant medications. No neuropsychologic test result is pathognomic for ADHD, and structural and functional neuroimaging studies have not identified a unique etiology for ADHD. No genetic marker has been consistently identified, and heritability studies are confounded by familial environmental factors. The validity of the Conners' Rating Scale-Revised has been seriously questioned, and parent and teacher "ratings" of school children are frequently discrepant, suggesting that use of subjective informant data via scale or interview does not form an objective basis for diagnosis of ADHD. Empiric diagnostic trials of stimulant medication that produce a behavioral response have been shown not to distinguish between children with and without "ADHD." In summary, the working dogma that ADHD is a disease or neurobehavioral condition does not at this time hold up to scrutiny of evidence. Thorough evaluation of symptomatic children should be individualized, and include assessment of educational, psychologic, psychiatric, and family needs.

Beverage caffeine intake in US consumers and subpopulations of interest: estimates from the Share of Intake Panel survey

Concerns exist about the potential adverse health effects of high consumption of dietary caffeine, especially in children and pregnant women. Recommended caffeine intakes corresponding to no adverse health effects have been suggested recently for healthy adults (400-450 mg/day), for women contemplating pregnancy (300 mg/day), and for young children age 4-6 years (45 mg/day). To determine whether current caffeine intake approaches these levels, intake from major dietary sources (coffee, tea and carbonated soft drinks) were measured in 10,712 caffeinated beverage consumers in the 1999 US Share of Intake Panel, a targeted beverage survey. Mean caffeine intakes in adult caffeinated beverage consumers ranged from 106 to 170 mg/day (90th percentile intake was 227-382 mg/day). In children 1-5 and 6-9 years, mean caffeine intakes were 14 and 22 mg/day, respectively; corresponding 90th percentile intakes were 37 and 45 mg/day. Pregnant women consumed an average of 58 mg/day (157 mg/day at the 90th percentile), and women of reproductive age ingested 91-109 mg/day (229-247 mg/day at the 90th percentile). These data show that while mean caffeine intakes are within recommended safe levels, heavy consumers of certain subpopulations, including young children and women contemplating pregnancy, might benefit from dietary advice.

Glucose effects on a continuous performance test of attention in adults

Increases in plasma blood glucose levels modulate memory, mood, and, to some extent, attention in adults. Participants in the present study were administered glucose (10, 100, and 500 mg/kg, or 50 g) or placebo (23.7 mg saccharin) shortly prior to completing the test of variables of attention (TOVA), a continuous performance test (CPT) commonly used to assess attention for diagnostic purposes. There were significant increases in blood glucose levels for the 500 mg/kg and 50 g groups, but only the 100 mg/kg group showed significant changes in behavior in comparison to the saccharin group. Specifically, the 100 mg/kg group performed worse on measures of commission errors, post-commission responses, and post-commission response time variability. There were no differences among the groups on other major variables of attention, including omission errors, response time, and response time variability. The results of this study demonstrate that large doses of glucose which increase blood glucose levels do not influence attention, but that a moderate dose (100 mg/kg) selectively impairs measures of impulsivity or disinhibition. Practitioners and researchers should maintain an awareness of dietary effects on attention and continue to examine micronutrients as potential confounds on diagnostic tests of cognition and behavior.

Effects of fexofenadine, diphenhydramine, and placebo on performance of the test of variables of attention (TOVA)

OBJECTIVE

To determine the effects of diphenhydramine 50 mg and fexofenadine 180 mg on cognitive performance using the Test of Variables of Attention (TOVA), and to ascertain whether the TOVA was sufficiently sensitive to differentiate between the effects of these first- and second-generation H1-receptor antagonists on performance.

STUDY DESIGN

The study used a double-blind, placebo-controlled, randomized, crossover design. Forty-two subjects completed four separate TOVA tests: at baseline and after administration of placebo, diphenhydramine 50 mg, and fexofenadine 180 mg. On each occasion, subjects rated subjective feelings of drowsiness on a visual analog scale (VAS) before taking the TOVA.

RESULTS

Compared with placebo, diphenhydramine caused an increased response time (P = 0.0230) and more omission errors (P = 0.0398). Diphenhydramine was also associated with increased drowsiness VAS ratings (P = 0.0065) compared with placebo. Diphenhydramine caused significantly more commission errors than fexofenadine (P = 0.0354). Neither placebonor fexofenadine 180 mg caused significant changes in any TOVA or VAS measurements compared with baseline. Fexofenadine was not statistically different from placebo for any evaluation.

CONCLUSIONS

The TOVA was sufficiently sensitive to differentiate between the central nervous system effects of fexofenadine and diphenhydramine. Fexofenadine 180 mg had no significant effect on the TOVA measures of performance or on self-reported drowsiness compared with placebo. In contrast, diphenhydramine 50 mg caused significant increases in omission errors and response time on the TOVA and increases in self-reported drowsiness compared with placebo [corrected].

Caffeine use and dependence in adolescents: one-year follow-up

The objectives were to conduct a 1-year follow-up of daily caffeine-using adolescents to further describe caffeine dependence symptoms and to determine whether caffeine dependence is associated with other substance dependence disorders. Twenty-one of 36 (58.3%) adolescents who participated in a study of caffeine dependence returned for follow-up. The previous study was a case series of adolescents who consumed caffeine daily and met some Diagnostic and Statistical Manual of Mental Disorders (fourth edition) substance dependence criteria as applied to caffeine. At follow-up, caffeine consumption from beverages was 179.9 +/- 151.8 mg/day. Of the 21 teenagers, 23.8% (n = 5) met criteria for caffeine dependence. Four of these participants developed caffeine dependence during the follow-up period. Other substance dependence disorders were not overrepresented in the caffeine dependent group compared to the caffeine nondependent group. The most commonly reported withdrawal symptoms in dependent teenagers (at baseline and follow-up combined) were feeling drowsy/tired, fatigued, or sluggish/slowed down (83.3% each) and headache (75.0%). Caffeine dependence occurs in some adolescents who drink caffeine daily and is marked by symptoms similar to those found in adults.

Effects of caffeine on human health

Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume </=300 mg caffeine per day (equivalent to 4.6 mg kg(-1) bw day(-1) for a 65-kg person) while children should consume </=2.5 mg kg(-1) bw day(-1).

Effects of caffeine on development and behavior in infancy and childhood: a review of the published literature

The Medline literature on the behavioral effects of caffeine in infants and children are reviewed. There has been little recent work in this area. Generally, caffeine is well tolerated in usual dietary amounts, and there is evidence that individuals differ in their susceptibility to caffeine-related adverse effects, which in turn may influence their consumption. Overall, the effects of caffeine in children seem to be modest and typically innocuous.

Caffeine dependence in teenagers

This study identifies and characterizes symptoms of caffeine dependence in adolescents. Thirty-six adolescents who consumed caffeine daily and had some features of caffeine dependence on telephone screen were scheduled for outpatient evaluation. Evaluation included the Diagnostic Interview Schedule for Children-IV-Youth Version (DISC-IV) and modified DISC-IV questions that assessed caffeine dependence based on DSM-IV substance dependence criteria. Of 36 subjects, 41.7% (n=15) reported tolerance to caffeine, 77.8% (n=28) described withdrawal symptoms after cessation or reduction of caffeine intake, 38.9% (n=14) reported desire or unsuccessful attempts to control use, and 16.7% (n=6) endorsed use despite knowledge of physical or psychological problems associated with caffeine. There was no significant difference in the amount of caffeine consumed daily by caffeine dependent versus non-dependent teenagers. These findings are important due to the vast number of adolescents who drink caffeinated beverages.

Continuous performance tests are sensitive to ADHD in adults but lack specificity. A review and critique for differential diagnosis

Historically, the focus for Attention Deficit Hyperactivity Disorder (ADHD) has been on children, with considerable research and many opinions available in this area. More recently, the focus has been expanded to include ADHD in adults. Assessment of ADHD in adults is complicated by the high rate of co-occurring disorders as well as symptom overlap with a number of disorders. One popular family of measures for the assessment of attention and executive control is the continuous performance test (CPT). A review of the available research on CPTs reveals that they are quite sensitive to CNS dysfunction. This is both a strength and a limitation of CPTs in that multiple disorders can result in impaired performance on a CPT. The high sensitivity of CPTs is further complicated by the multiple variations of CPTs available, some of which may be more sensitive or demonstrate better specificity to ADHD in adults than others. If CPTs are to be used clinically, further research will be needed to answer the questions raised by this review.

The plus-maze discriminative avoidance task: a new model to study memory-anxiety interactions. Effects of chlordiazepoxide and caffeine

The plus-maze discriminative avoidance paradigm is a new animal model of learning/memory that provides simultaneous information about anxiety. Mice are conditioned to choose between the two enclosed arms (in one of which light and noise are presented as aversive stimuli) while avoiding the two open arms of the apparatus. The test has the advantage of measuring, at the same time and in the same animals, learning/memory (by the percent time spent in aversive enclosed arm - PTAV) and anxiety (by the percent time spent in the open arms - PTO). The effects of chlordiazepoxide and caffeine on learning/memory and anxiety of mice tested in this paradigm were investigated. Chlordiazepoxide (5 mg/kg) significantly increased and caffeine (20 mg/kg) significantly decreased PTO during the training session, suggesting an anxiolytic and an anxiogenic effect, respectively. In the test session, chlordiazepoxide- or caffeine-treated mice presented higher PTAV, suggesting amnestic effects. Given together, chlordiazepoxide plus caffeine did not alter PTO, and the amnesic effect produced by each drug was no longer observed. It is concluded that learning/memory depends on an optimum emotional level. The plus-maze discriminative avoidance model appears to be a useful test to investigate this critical relationship between learning/memory and anxiety.

Initial tobacco use episodes in children and adolescents: current knowledge, future directions

Approximately three-quarters of adult tobacco users report that their first tobacco use occurred between ages 11 and 17, while many adults who do not regularly use tobacco report that they experimented with it as adolescents. Surprisingly little is known about the effects of these initial tobacco use episodes and their influence on adult tobacco use patterns. In particular, understanding the role that nicotine plays in these early tobacco use experiences may be important in understanding the development of regular tobacco use and concomitant nicotine dependence. One goal of this review is to summarize current knowledge regarding the effects of initial tobacco use episodes in adolescents and to discuss nicotine exposure in initial tobacco use episodes. Another goal is to outline a research agenda designed to learn more about initial tobacco use episodes and the effects of nicotine in children. An ethical rationale and some potential methods for this research agenda are presented.