Caffeine dependence in schoolchildren?

Acute Effects of Low Dose of Caffeine Ingestion Combined with Conditioning Activity on Psychological and Physical Performances of Male and Female Taekwondo Athletes

This study investigated low-dose caffeine ingestion, conditioning activity (CA) effects on psycho-physical performances in young taekwondo athletes. In a randomized, double-blind, counterbalanced, crossover design, 20 athletes (10 males; 17.5 ± 0.7 yrs) performed taekwondo-specific agility test (TSAT), 10 s/multiple frequency speed of kick test (FSKT-10s/FSKT-mult) after ingesting 3 mg·kg−1 caffeine (CAF) or placebo (PL) 60 min before performing standard warm-up without (NoCA) or with CA (3 × 10 vertical jumps above 40 cm), resulting in four experimental (PL + NoCA, CAF + NoCA, PL + CA, and CAF + CA) and one control (warm-up session without CAF or CA) conditions. Mood/physical symptoms (MPSS), subjective vitality (SVS), and feeling (FS) scales were analyzed post-to-pre for all conditions. Ratings of perceived-exertion and perceived-recovery status were determined after tests. For TSAT, CAF + CA induced better performance compared with all conditions (p < 0.001). For FSKT-10s and FSKT-mult, CAF + CA induced better performance compared with all conditions (p < 0.001). For MPSS, FS, CAF + NoCA induced higher scores than PL + NoCA and PL + CA (p = 0.002, 0.009 for MPSS; p = 0.014, 0.03 for FS). For SVS, PL + CA elicited lower scores than PL + NoCA and CAF + NoCA (p = 0.01, 0.004). Sex comparisons resulted in better performances for males for TSAT (p = 0.008), FSKT-10s (p < 0.001), FSKT-mult (p < 0.01), MPSS (p = 0.02), SVS (p = 0.028), and FS (p = 0.020) scores. Caffeine and conditioning activity are two efficient performance-enhancing strategies, which could synergistically result in greater psycho-physical performances.

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.

Is the Consumption of Energy Drinks Associated With Academic Achievement Among College Students?

Despite widely reported side effects, use of energy drinks has increased among college students, who report that they consume energy drinks to help them complete schoolwork. However, little is known about the association between energy drink use and academic performance. We explored the relationship between energy drink consumption and current academic grade point average (GPA) among first-year undergraduate students. Participants included 844 first-year undergraduates (58.1 % female; 50.7 % White). Students reported their health behaviors via an online survey. We measured energy drink consumption with two measures: past month consumption by number of drinks usually consumed in 1 month and number consumed during the last occasion of consumption. We used multiple linear regression modeling with energy drink consumption and current GPA, controlling for gender, race, weekend and weekday sleep duration, perceived stress, perceived stress management, media use, and past month alcohol use. We found that past month energy drink consumption quantity by frequency (p < 0.001), and energy drinks consumed during the last occasion (p < 0.001), were associated with a lower GPA. Energy drinks consumed during the last occasion of consumption (p = 0.01) remained significantly associated with a lower GPA when controlling for alcohol use. While students report using energy drinks for school-related reasons, our findings suggest that greater energy drink consumption is associated with a lower GPA, even after controlling for potential confounding variables. Longitudinal research is needed that addresses whether GPA declines after continued use of energy drinks or if students struggling academically turn to energy drinks to manage their schoolwork.

Association between energy drink intake, sleep, stress, and suicidality in Korean adolescents: energy drink use in isolation or in combination with junk food consumption

BACKGROUND

A considerable amount of research suggests that the frequent use of caffeinated energy drinks may be associated with undesirable effects, particularly so in children and adolescents. This study aimed to investigate the associations between energy drink intake and mental health problems, in isolation or in combination with junk food consumption, in a nationally representative sample of Korean adolescents.

METHODS

Data from the 2015 Korean Youth Risk Behavior Web-Based Survey, collected from 68,043 adolescents aged 12-18 years (mean age 15.09 ± 1.72 years), were analyzed. Questionnaires were administered to collect information related to dietary behavior including energy drink intake and junk food consumption. Single item measures of sleep dissatisfaction, stress, depression, suicidal ideation, suicide plan, and suicide attempt were also administered. Associations between energy drink intake and sleep dissatisfaction, perceived severe stress, persistent depressive mood, and suicidality were investigated, and a multivariate approach was taken so that additional variance from demographic and lifestyle factors could be controlled for statistically.

RESULTS

Energy drink intake was significantly associated with sleep dissatisfaction (adjusted odd ratios [AORs] = 1.64 and 1.25), severe stress (AORs = 2.23 and 1.38), depressive mood (AOR = 2.59 and 1.51), suicidal ideation (AORs = 3.14 and 1.43), suicide plan (AORs = 4.65 and 1.78), and suicide attempt (AORs = 6.79 and 1.91), with a higher risk for more frequent use of energy drinks (≥5 times/wk) than for less frequent use (1-4 times/wk). The detrimental effect of energy drinks on mental health was particularly prominent in frequent junk food consumers.

CONCLUSIONS

Our data suggest that energy drink intake had detrimental effects related to stress, sleep dissatisfaction, mood, and suicidality, in isolation or in combination with junk food consumption, in Korean adolescents. However, the cross-sectional study design prevents our ability to assess causal relationships.

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.

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.

Problematic use of energy drinks by adolescents

Energy drinks (EDs) are caffeine-based beverages that commonly contain large doses of sugar, carbohydrates, and a variety of legal stimulants and supplements, such as guarana, taurine, ginseng, and vitamin B complex. These drinks are marketed for young people as natural alternatives that increase fun and improve physical and cognitive performance such as concentration, attention, and alertness. There are commonly held false perceptions that the consumption of EDs can reverse alcohol-related impairment, including motor coordination and visual reaction time, which are crucial for driving safety. This article reviews the literature on EDs and examines problematic use and potential negative consequences in young people. Special emphasis is devoted to safety concerns following combination of EDs with alcohol, which gives the user a false sense of control.

Understanding Adolescent Caffeine Use: Connecting Use Patterns With Expectancies, Reasons, and Sleep

Little is known about adolescents’ caffeine use, yet caffeinated soda, and more recently coffee and energy drinks, are part of youth culture. This study examines adolescents’ caffeine use and, using cluster analysis, identifies three groups of caffeine users who differed in their reasons for use, expectancies, and sleep behaviors. In this high school student sample ( N = 197), 95% of participants reported recent caffeine use—most often soda—where typical first use of the day was in the evening. Results reveal that adolescents in the mixed use and high soda use groups consumed similar amounts of soda, reporting significantly more use than the low caffeine use group. In contrast with high soda users, mixed users drank more coffee, expected more dependence symptoms and energy enhancement from caffeine, and were more likely to report getting up early, daytime sleepiness, and using caffeine to get through the day.

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.

Caffeinated energy drinks--a growing problem

Since the introduction of Red Bull in Austria in 1987 and in the United States in 1997, the energy drink market has grown exponentially. Hundreds of different brands are now marketed, with caffeine content ranging from a modest 50 mg to an alarming 505 mg per can or bottle. Regulation of energy drinks, including content labeling and health warnings differs across countries, with some of the most lax regulatory requirements in the U.S. The absence of regulatory oversight has resulted in aggressive marketing of energy drinks, targeted primarily toward young males, for psychoactive, performance-enhancing and stimulant drug effects. There are increasing reports of caffeine intoxication from energy drinks, and it seems likely that problems with caffeine dependence and withdrawal will also increase. In children and adolescents who are not habitual caffeine users, vulnerability to caffeine intoxication may be markedly increased due to an absence of pharmacological tolerance. Genetic factors may also contribute to an individual's vulnerability to caffeine-related disorders including caffeine intoxication, dependence, and withdrawal. The combined use of caffeine and alcohol is increasing sharply, and studies suggest that such combined use may increase the rate of alcohol-related injury. Several studies suggest that energy drinks may serve as a gateway to other forms of drug dependence. Regulatory implications concerning labeling and advertising, and the clinical implications for children and adolescents are discussed.

Effects of caffeine and coffee consumption on cardiovascular disease and risk factors

Clinical and observational studies have recently reported that coffee consumption is associated with cardiac arrhythmia, with increased serum cholesterol, blood pressure and affected heart rate variability, leading to an increased cardiovascular risk. Analysis of these papers shows that these data are controversial and strongly depend on methodology. Recent reports demonstrate the beneficial effects of coffee consumption due to anti-inflammatory actions mediated by antioxidant compound of the beverages.

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.

A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features

RATIONALE

Although reports of caffeine withdrawal in the medical literature date back more than 170 years, the most rigorous experimental investigations of the phenomenon have been conducted only recently.

OBJECTIVES

The purpose of this paper is to provide a comprehensive review and analysis of the literature regarding human caffeine withdrawal to empirically validate specific symptoms and signs, and to appraise important features of the syndrome.

METHODS

A literature search identified 57 experimental and 9 survey studies on caffeine withdrawal that met inclusion criteria. The methodological features of each study were examined to assess the validity of the effects.

RESULTS

Of 49 symptom categories identified, the following 10 fulfilled validity criteria: headache, fatigue, decreased energy/activeness, decreased alertness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability, and foggy/not clearheaded. In addition, flu-like symptoms, nausea/vomiting, and muscle pain/stiffness were judged likely to represent valid symptom categories. In experimental studies, the incidence of headache was 50% and the incidence of clinically significant distress or functional impairment was 13%. Typically, onset of symptoms occurred 12-24 h after abstinence, with peak intensity at 20-51 h, and for a duration of 2-9 days. In general, the incidence or severity of symptoms increased with increases in daily dose; abstinence from doses as low as 100 mg/day produced symptoms. Research is reviewed indicating that expectancies are not a prime determinant of caffeine withdrawal and that avoidance of withdrawal symptoms plays a central role in habitual caffeine consumption.

CONCLUSIONS

The caffeine-withdrawal syndrome has been well characterized and there is sufficient empirical evidence to warrant inclusion of caffeine withdrawal as a disorder in the DSM and revision of diagnostic criteria in the ICD.

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 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.

Effects of caffeine on human behavior

The literature suggests that the following effects on behavior of adult humans may occur when individuals consume moderate amounts of caffeine. (1) Caffeine increases alertness and reduces fatigue. This may be especially important in low arousal situations (e.g. working at night). (2) Caffeine improves performance on vigilance tasks and simple tasks that require sustained response. Again, these effects are often clearest when alertness is reduced, although there is evidence that benefits may still occur when the person is unimpaired. (3) Effects on more complex tasks are difficult to assess and probably involve interactions between the caffeine and other variables which increase alertness (e.g. personality and time of day). (4) In contrast to the effects of caffeine consumption, withdrawal of caffeine has few effects on performance. There is often an increase in negative mood following withdrawal of caffeine, but such effects may largely reflect the expectancies of the volunteers and the failure to conduct "blind" studies. (5) Regular caffeine usage appears to be beneficial, with higher users having better mental functioning. (6) Most people are very good at controlling their caffeine consumption to maximise the above positive effects. For example, the pattern of consumption over the day shows that caffeine is often consumed to increase alertness. Indeed, many people do not consume much caffeine later in the day since it is important not to be alert when one goes to sleep. In contrast to effects found from normal caffeine intake, there are reports that have demonstrated negative effects when very large amounts are given or sensitive groups (e.g. patients with anxiety disorders) were studied. In this context caffeine has been shown to increase anxiety and impair sleep. There is also some evidence that fine motor control may be impaired as a function of the increase in anxiety. Overall, the global picture that emerges depends on whether one focuses on effects that are likely to be present when caffeine is consumed in moderation by the majority of the population or on the effects found in extreme conditions. The evidence clearly shows that levels of caffeine consumed by most people have largely positive effects on behavior. Excessive consumption can lead to problems, especially in sensitive individuals.

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.