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

Association between dietary caffeine intake and severe headache or migraine in US adults

The relationship between current dietary caffeine intake and severe headache or migraine is controversial. Therefore, we investigated the association between dietary caffeine intake and severe headaches or migraines among American adults. This cross-sectional study included 8993 adults (aged ≥ 20 years) with a dietary caffeine intake from the National Health and Nutrition Examination Surveys of America from 1999 to 2004. Covariates, including age, race/ethnicity, body mass index, poverty-income ratio, educational level, marital status, hypertension, cancer, energy intake, protein intake, calcium intake, magnesium intake, iron intake, sodium intake, alcohol status, smoking status, and triglycerides, were adjusted in multivariate logistic regression models. In US adults, after adjusting for potential confounders, a 100 mg/day increase in dietary caffeine intake was associated with a 5% increase in the prevalence of severe headache or migraine (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.02-1.07). Further, the prevalence of severe headache or migraine was 42% higher with caffeine intake of ≥ 400 mg/day than with caffeine intake of ≥ 0 to < 40 mg/day (OR 1.42, 95% CI 1.16-1.75). Conclusively, dietary caffeine intake is positively associated with severe headaches or migraines in US adults.

Characterization of childhood exposure to environmental contaminants using stool in a semi-urban middle-class cohort from eastern Canada

Children are exposed to various environmental organic and inorganic contaminants with effects on health outcomes still largely unknown. Many matrices (e.g., blood, urine, nail, hair) have been used to characterize exposure to organic and inorganic contaminants. The sampling of feces presents several advantages; it is non-invasive and provides a direct evaluation of the gut microbiome exposure to contaminants. The gut microbiome is a key factor in neurological development through the brain-gut axis. Its composition and disturbances can affect the neurodevelopment of children. Characterization of children exposure to contaminants is often performed on vulnerable populations (e.g., from developing countries, low-income neighborhoods, and large urban centers). Data on the exposure of children from middle-class, semi-urban, and mid-size populations to contaminants is scarce despite representing a significant fraction of the population in North America. In this study, 73 organics compounds from different chemical classes and 22 elements were analyzed in 6 years old (n = 84) and 10 years old (n = 119) children's feces from a middle-class, semi-urban, mid-size population cohort from Eastern Canada. Results show that 67 out of 73 targeted organics compounds and all elements were at least detected in one child's feces. Only caffeine (97% & 80%) and acetaminophen (28% & 48%) were detected in more than 25% of the children's feces, whereas all elements besides titanium were detected in more than 50% of the children.

Sleepy Teens and Energy Drink Use: Results From an Ethnically Diverse Sample of Youth

This study examines the association between use of energy drinks or products (EP), EP expectancies, and the association between EP use and sleep in a racially and ethnically diverse sample (N = 2,485) of adolescents. Prevalence of EP use was approximately 18%, with no statistically significant racial or ethnic differences in prevalence. There were significant racial and ethnic differences in EP expectancies; Hispanic and Multiracial or Other groups endorsed less positive expectancies than Whites and Asians. EP use was significantly associated with later weekend bedtimes, shorter weekend total sleep time (TST), a smaller weekend-weekday difference in TST, and more trouble sleeping, even after adjusting for covariates. There were no significant race or ethnicity interactions between EP use and sleep. EP use is an independent correlate of sleep problems in adolescents across racial or ethnic groups.

Does early exposure to caffeine promote smoking and alcohol use behavior? A prospective analysis of middle school students

BACKGROUND AND AIMS

Despite the negative consequences associated with caffeine use among children and youth, its use is increasingly widespread among middle school students. Cross-sectional studies reveal links between caffeine and other substance use. The potential for caffeine use to confer increased vulnerability to substance use, however, has not been investigated using prospective designs. We hypothesized that caffeine use at baseline would be associated positively with increased alcohol use, drunkenness, smoking and e-cigarette use.

DESIGN

Prospective cohort study with 12 months separating baseline from follow-up.

SETTING

West Virginia, USA.

PARTICIPANTS

Middle school students (6th and 7th grades; n = 3932) in three West Virginia (WV) counties provided data at baseline and follow-up 12 months later.

MEASUREMENTS

Youth self-reported their use of caffeine from multiple sources (e.g. soda, energy drinks, coffee and tea), cigarette smoking, electronic cigarette use, alcohol use and drunkenness.

FINDINGS

Cross-lagged path models for individual substance use categories provided a good fit to the data. Controlling for demographic variables and other substance use at baseline, caffeine at time 1 (T1) was associated positively with T2 cigarette smoking (β = 0.27, P = 0.001), e-cigarette use (β = 0.21, P = 0.001), alcohol use (β = 0.17, P = 0.001) and drunkenness (β = 0.15, P = 0.001). Conversely, non-significant relations emerged between three of four substances at T1 and caffeine at T2. Positive relations were found between e-cigarette use at T1 and caffeine use at T2 (β = 0.07, P = 0.006). These findings were supported by an omnibus model with all substances included. Specifically, significant relations were observed between caffeine at T1 and all substance use outcomes at T2, whereas no significant relations were observed between substance use and caffeine over time.

CONCLUSIONS

Caffeine may promote early use of other types of substances among middle school-aged adolescents.

Concurrent Validity of Caffeine Problems and Diagnostic Criteria for Substance Use Disorders

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. Descriptive analyses were used to determine prevalence of CUD and frequency of each endorsed SUD criterion as applied to caffeine versus alcohol or marijuana. Comparative Fit Index (CFI) and Tucker-Lewis Index (TLI) were used to determine psychometric properties for CUD. Results: The majority of subjects (N = 153) reported past 30-day caffeine use and of these, six (4%) met criteria for CUD. All six also met criteria for either alcohol and/or marijuana use disorders. Of the three essential CUD criteria (failure to quit, use despite harm, and withdrawal), both harm and withdrawal were endorsed significantly more often in relation to caffeine versus alcohol. Descriptive fit indices for the CUD model were excellent (CFI = 0.994, TLI = 0.991). Conclusions: In our sample, the proportion of adolescents that met proposed CUD criteria was low, suggesting that the proposed criteria would not lead to overdiagnosis of CUD. CUD was highly correlated with other SUDs.

Intralipid in acute caffeine intoxication: a case report

Caffeine is arguably the most widely used stimulant drug in the world. Here we describe a suicide attempt involving caffeine overdose whereby the patient's severe intoxication was successfully treated with the prompt infusion of Intralipid. A 19-year-old man was found in an agitated state at home by the volunteer emergency team about 1 h after the intentional ingestion of 40 g of caffeine (tablets). His consciousness decreased rapidly, followed quickly by seizures, and electrocardiographic monitoring showed ventricular fibrillation. Advanced life support maneuvers were started immediately, with the patient defibrillated 10 times and administered 5 mg epinephrine in total and 300 + 150 mg of amiodarone (as well as lidocaine and magnesium sulfate). The cardiac rhythm eventually evolved to asystole, necessitating the intravenous injection of epinephrine to achieve the return of spontaneous circulation. However, critical hemodynamic instability persisted, with the patient's cardiac rhythm alternating between refractory irregular narrow complex tachycardia and wide complex tachycardia associated with hypotension. In an attempt to restore stability we administered three successive doses of Intralipid (120 + 250 + 100 mg), which successfully prevented a severe cardiovascular collapse due to a supra-lethal plasma caffeine level (>120 mg/L after lipid emulsion). The patient survived without any neurologic complications and was transferred to a psychiatric ward a few days later. The case emphasizes the efficacy of intravenous lipid emulsion in the resuscitation of patients from non-local anesthetic systemic toxicity. Intralipid appears to act initially as a vehicle that carries the stimulant drug away from heart and brain to less well-perfused organs (scavenging mechanism) and then, with a sufficient drop in the caffeine concentration, possibly as a tonic to the depressed heart.

Caffeine: cognitive and physical performance enhancer or psychoactive drug?

Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine’s mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine’s interaction with other substances or to the individuals' preexisting metabolism alterations or diseases.

A brief manualized treatment for problematic caffeine use: A randomized control trial

OBJECTIVE

The goal of the present investigation was to develop and test a brief therapist-guided manualized treatment for problematic caffeine use, including cognitive-behavioral strategies and 5 weeks of progressively decreased consumption.

METHOD

Individuals seeking treatment for problematic caffeine use (mean daily caffeine consumption of 666 mg at baseline) were randomized using a waitlist-control design to receive immediate treatment (N = 33) or delayed treatment (∼6 weeks later; N = 34). A 1-hr treatment session designed to help individuals quit or reduce caffeine consumption was provided by a trained counselor along with a take-home booklet. After the treatment session, participants completed daily diaries of caffeine consumption for 5 weeks. They returned for follow-up assessments at 6, 12, and 26 weeks and had a telephone interview at 52-weeks posttreatment.

RESULTS

Treatment resulted in a significant reduction in self-reported caffeine use and salivary caffeine levels. No significant posttreatment increases in caffeine use were observed for up to 1 year follow-up. Comparisons to the waitlist-control condition revealed that reductions in caffeine consumption were due to treatment and not the passing of time, with a treatment effect size of R² = .35 for the model.

CONCLUSION

A brief 1-session manualized intervention with follow-up was efficacious at reducing caffeine consumption. Future researchers should replicate and extend these findings, as well as consider factors affecting dissemination of treatment for problematic caffeine use to those in need.

Evaluating the Validity of Caffeine Use Disorder

Caffeine use disorder is included in the conditions for further study section of the DSM-5. Caffeine's profile of neurobiological, behavioral, and clinical effects is similar to other common substances that humans use recreationally. Extant data suggest that a clinically meaningful addictive disorder develops in some regular caffeine users, but this literature is incomplete and not yet sufficient to determine if and how best to define and treat caffeine use disorder. An overview of the literature relevant to determining the clinical importance of problematic caffeine use is followed by discussion of potential concerns and benefits associated with its classification as a mental disorder. Concerns about overdiagnosis and trivialization of other psychiatric syndromes are weighed against the public health benefits of increased awareness and development of interventions targeting problematic caffeine use. This discussion includes consideration of alternative diagnostic approaches, improvement of assessment practices, and the need for additional clinical and epidemiological research.

College students' use of energy drinks, social problem-solving, and academic performance

Energy drink (ED) use among college students to improve academic performance (AP) has skyrocketed. A growing body of literature indicates that the risks associated with ED use may outweigh the perceived benefits. In this study, 486 undergraduates were surveyed on their general substance and ED usage, Social Problem-Solving (SPS) ability, and AP. It was hypothesized that: (1) ED use would be a negative predictor of AP; (2) SPS would be a positive predictor of AP; (3) SPS would be a negative predictor of ED use; and (4) SPS and ED use would account for a significant amount of the variance in AP. A linear multiple regression for AP was conducted, with predictor variables entered in the following order: total drug use, non-ED caffeine use, SPS, and ED use. The overall model was significant and accounted for approximately 7% of the variance in AP. The hypotheses of the study were supported, indicating that ED use may be related to decreased AP, SPS ability may be related to increased AP, or that students with poor AP and less effective SPS skills are more likely to use EDs. Implications of these findings are important for college students and other users of ED products.

Caffeine Use Disorder: A Comprehensive Review and Research Agenda

Caffeine is the most commonly used drug in the world. Although consumption of low to moderate doses of caffeine is generally safe, an increasing number of clinical studies are showing that some caffeine users become dependent on the drug and are unable to reduce consumption despite knowledge of recurrent health problems associated with continued use. Thus, the World Health Organization and some health care professionals recognize caffeine dependence as a clinical disorder. In this comprehensive literature review, we summarize published research on the biological evidence for caffeine dependence; we provide a systematic review of the prevalence of caffeine dependence and rates of endorsement of clinically meaningful indicators of distress and functional impairment among habitual caffeine users; we discuss the diagnostic criteria for Caffeine Use Disorder-a condition for further study included in the Diagnostic and Statistical Manual of Mental Disorders (5^th ed.); and we outline a research agenda to help guide future clinical, epidemiological, and genetic investigations of caffeine dependence. Numerous controlled laboratory investigations reviewed in this article show that caffeine produces behavioral and physiological effects similar to other drugs of dependence. Moreover, several recent clinical studies indicate that caffeine dependence is a clinically meaningful disorder that affects a nontrivial proportion of caffeine users. Nevertheless, more research is needed to determine the reliability, validity, and prevalence of this clinically important health problem.

Caffeinated Alcoholic Beverages - An Emerging Trend in Alcohol Abuse

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

Caffeine Withdrawal and Dependence: A Convenience Survey Among Addiction Professionals

AIMS

Caffeine withdrawal was included in the research appendix of the DSM-IV to encourage additional research to assist with determining its status for the next version of the manual. Caffeine dependence was not included because of a lack of empirical research at the time of publication. This study assessed the beliefs of addiction professionals about the clinical importance of caffeine withdrawal and dependence.

METHODS

A 6-item survey was developed and delivered electronically to the members of six professional organizations that focus on addiction. Open-ended comments were also solicited. Five hundred members responded.

RESULTS

The majority (95%) thought that cessation of caffeine could produce a withdrawal syndrome, and that caffeine withdrawal can have clinical importance (73%); however, only half (48%) thought that caffeine withdrawal should be included in the Diagnostic and Statistical Manual of Mental Disorders (DSM). A majority (58%) believed that some people develop caffeine dependence; however, only 44% indicated that it should be in the DSM. Comments suggested that trepidation about inclusion of caffeine diagnoses was due to the concerns about the field of psychiatry being criticized for including common disorders with a relatively low clinical severity. Others, however, expressed an urgent need to take caffeine-related problems more seriously.

CONCLUSIONS

The majority of addiction professionals believe that caffeine withdrawal and dependence disorders exist and are clinically important; however, these professionals are divided in whether caffeine withdrawal and dependence should be included in DSM. Wider dissemination of the extant literature on caffeine withdrawal and additional research on caffeine dependence will be needed to provide additional guidance to policymakers and healthcare workers.

Alcohol, nicotine, caffeine, and mental disorders

Alcohol, nicotine, and caffeine are the most widely consumed psychotropic drugs worldwide. They are largely consumed by normal individuals, but their use is even more frequent in psychiatric patients, Thus, patients with schizophrenia tend to abuse all three substances. The interrelationships between depression and alcohol are complex. These drugs can all create dependence, as understood in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Alcohol abuse is clearly deleterious to the brain, provoking acute and chronic mental disorders, ranging from intoxication with impairment of cognition, to delirium tremens, halluosis, and dementia. In contrast, the main health consequences of nicotine, notably cancer and cardiovascular disases, lie outside the realm of psychiatry However, the mes of nicotine dependence and motivation to smoke or quit are of concern to psychiatrists.

Characterization of individuals seeking treatment for caffeine dependence

Previous investigations have identified individuals who meet criteria for Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) substance dependence as applied to caffeine, but there is little research on treatments for caffeine dependence. This study aimed to thoroughly characterize individuals who are seeking treatment for problematic caffeine use. Ninety-four individuals who identified as being psychologically or physically dependent on caffeine, or who had tried unsuccessfully to modify caffeine consumption participated in a face-to-face diagnostic clinical interview. They also completed measures concerning caffeine use and quitting history, reasons for seeking treatment, and standardized self-report measures of psychological functioning. Caffeine treatment seekers (mean age 41 years, 55% women) consumed an average of 548 mg caffeine per day. The primary source of caffeine was coffee for 50% of the sample and soft drinks for 37%. Eighty-eight percent reported prior serious attempts to modify caffeine use (mean 2.7 prior attempts), and 43% reported being advised by a medical professional to reduce or eliminate caffeine. Ninety-three percent met criteria for caffeine dependence when generic DSM-IV-TR substance dependence criteria were applied to caffeine use. The most commonly endorsed criteria were withdrawal (96%), persistent desire or unsuccessful efforts to control use (89%), and use despite knowledge of physical or psychological problems caused by caffeine (87%). The most common reasons for wanting to modify caffeine use were health-related (59%) and not wanting to be dependent on caffeine (35%). This investigation reveals that there are individuals with problematic caffeine use who are seeking treatment and suggests that there is a need for effective caffeine dependence treatments.

Evaluating Dependence Criteria for Caffeine

Background: Although caffeine is the most widely used mood-altering drug in the world, few studies have operationalized and characterized Diagnostic and Statistical Manual IV (DSM-IV) substance dependence criteria applied to caffeine. Methods: As a part of a nosological study of substance use disorders funded by the National Institute on Drug Abuse, we assessed caffeine use and dependence symptoms among high school and college students, drug treatment patients, and pain clinic patients who reported caffeine use in the last 7 days and also reported use of alcohol, nicotine, or illicit drugs within the past year (n=167). Results: Thirty-five percent met the criteria for dependence when all seven of the adopted DSM dependence criteria were used. Rates of endorsement of several of the most applicable diagnostic criteria were as follows: 26% withdrawal, 23% desire to cut down or control use, and 44% continued use despite harm. In addition, 34% endorsed craving, 26% said they needed caffeine to function, and 10% indicated that they talked to a physician or counselor about problems experienced with caffeine. There was a trend towards increased caffeine dependence among those dependent on nicotine or alcohol. Within a subgroup that had used caffeine, alcohol, and nicotine in the past year, 28% fulfilled criteria for caffeine dependence compared to 50% for alcohol and 80% for nicotine. Conclusion: The present study adds to a growing literature suggesting the reliability, validity, and clinical utility of the caffeine dependence diagnosis. Recognition of caffeine dependence in the DSM-V may be clinically useful.

Acute and adaptive motor responses to caffeine in adolescent and adult rats

Caffeine is a psychostimulant with intake through foods or beverages tending to increase from childhood through adolescence. The goals of the present study were to examine the effects of caffeine on young adolescent Long-Evans rats and to compare the motor-behavioral responses of adolescent and adult rats to acute and chronic caffeine. Adolescent rats had a biphasic dose-response to caffeine comparable to that reported for adult rats. The magnitude of the motor response to a challenge dose of caffeine (30mg/kg, ip) was similar between adolescent and adult rats. Administration of caffeine in the drinking water (1mg/ml) for a period of 2 weeks led to overall consumption of caffeine which was not significantly different between adolescents and adults when normalized to body mass. There were no impacts of caffeinated drinking water on volume of fluid consumed nor weight gain in either age group compared to age matched controls drinking non-caffeinated tap water. Following this period of caffeine consumption, return to regular drinking water (caffeine withdrawal) led to a significant decrease in baseline movement compared to caffeine-naïve rats. This effect inversion was observed for adolescents but not adults. In addition, the response of the adolescents to the challenge dose of caffeine (30mg/kg, ip) was reduced significantly after chronic caffeine consumption and withdrawal. This apparent tolerance to the caffeine challenge dose was not seen with the adults. Thus, the developing brain of these adolescents may show similar sensitivity to adults in acute caffeine exposure but greater responsiveness to adaptive changes associated with chronic caffeine consumption.

Gender Differences in Subjective and Physiological Responses to Caffeine and the Role of Steroid Hormones

BACKGROUND

We have shown previously that male and female adolescents differ in their responses to caffeine, but to date, the mechanisms underlying these gender differences are unknown.

OBJECTIVE

The purpose of this study was to test the hypothesis that differences in circulating steroid hormones mediate gender differences in response to caffeine.

METHODS

Subjective and physiological responses to caffeine were tested in adolescents using a double-blind, placebo controlled, crossover design. Participants were tested every 2 weeks for 8 weeks and received placebo and caffeine (2 mg/kg) twice each. Females were tested with placebo and caffeine in each phase of their menstrual cycle. Salivary concentrations of testosterone, estradiol, and progesterone were also measured.

RESULTS

Males showed greater positive subjective effects than females. In females, higher levels of estradiol were associated with little or no subjective responses to caffeine, but lower levels of estradiol were associated with negative subjective responses to caffeine relative to placebo. There were gender differences in cardiovascular responses to caffeine, with males showing greater decreases in heart rate after caffeine administration than females, but females showing greater increases in diastolic blood pressure than males after caffeine administration. These gender differences may be related to steroid hormone concentrations. Blood pressure responses to caffeine were lower in males when estradiol was high, but higher in females when estradiol was high.

CONCLUSIONS

When taken together, these findings suggest that males and females differ in their responses to caffeine and that these differences may be mediated by changes in circulating steroid hormones.

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.

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.

Hospitalization for caffeine abuse is associated with abuse of other pharmaceutical products

STUDY OBJECTIVE

The aim of this study was to examine the characteristics and outcomes of patients seeking treatment for abuse of supplemental caffeine.

METHODS

This was a 3-year analysis conducted of all consecutive cases involving caffeine abuse in patients 10 years and older reported to a regional poison center. Excluded were suicide attempts, therapeutic errors, and cases involving only a coffee or tea product.

RESULTS

Two hundred fifty-four cases met inclusion criteria. Mean age was 20.5 years, 50% were women. Caffeine was in the form of a nondietary medication in 201 cases, a dietary supplement in 35 cases, and a caffeine-enhanced beverage in 35 cases. Caffeine was abused alone in 174 (68%), with alcohol in 7, illegal drugs in 6 cases, and with other pharmaceutical products in 81 (29%) cases. Thirty-four patients (13% of total) were hospitalized for medical complications from caffeine. Only concomitant abuse of other pharmaceutical products was associated with hospitalization (odds ratio, 3.8; 95% CI, 1.8-8.8; P = .0004).

CONCLUSION

In this cohort, supplemental caffeine was abused primarily by young adults. Concomitant recreational abuse of other pharmaceuticals was associated with hospitalization and warrants further investigation.

Caffeine: sleep and daytime sleepiness

Caffeine is one of the most widely consumed psychoactive substances and it has profound effects on sleep and wake function. Laboratory studies have documented its sleep-disruptive effects. It clearly enhances alertness and performance in studies with explicit sleep deprivation, restriction, or circadian sleep schedule reversals. But, under conditions of habitual sleep the evidence indicates that caffeine, rather then enhancing performance, is merely restoring performance degraded by sleepiness. The sleepiness and degraded function may be due to basal sleep insufficiency, circadian sleep schedule reversals, rebound sleepiness, and/or a withdrawal syndrome after the acute, over-night, caffeine discontinuation typical of most studies. Studies have shown that caffeine dependence develops at relatively low daily doses and after short periods of regular daily use. Large sample and population-based studies indicate that regular daily dietary caffeine intake is associated with disturbed sleep and associated daytime sleepiness. Further, children and adolescents, while reporting lower daily, weight-corrected caffeine intake, similarly experience sleep disturbance and daytime sleepiness associated with their caffeine use. The risks to sleep and alertness of regular caffeine use are greatly underestimated by both the general population and physicians.

Caffeine use by children: the quest for enhancement

Fair play, both in academics and sports, is a concept that is challenged by the notion of performance enhancement. Both cognitive and physical performance can be viewed as potentially enhanceable, and arguments can be made that enhancement can serve two purposes: gaining an edge or keeping up with others (who may or may not have used performance-enhancing substances). Caffeine, a central nervous system and cardiac stimulant, is frequently used by children for both academic and athletic performance enhancement. In fact, the marketplace contains a plethora of caffeinated products marketed directly to children. This article examines safety and ethical issues associated with the use of caffeine by children and explores the question: Can cognitive performance enhancement be ethically permissible if sports performance enhancement is not?

Caffeine as a flavor additive in soft-drinks

Over 60% of soft-drinks sold in the United States contain caffeine, a mildly addictive psycho-active chemical, as a flavor additive. Using sweeteners as controls, we assessed whether caffeine has flavor activity in a cola soft-drink. A forced-choice triangle discrimination methodology was used to determine detection thresholds of caffeine in sweeteners and a cola beverage. The subjects (n=30, 28 female, 23+/-4 years old) were trained tasters and completed over 1600 discrimination tests during the study. The mean detection thresholds for caffeine in the sweet solutions were: 0.333+/-0.1mM sucrose; 0.467+/-0.29 mM aspartame; 0.462+/-0.3mM sucralose, well below the concentration in common cola beverages (0.55-0.67 mM). A fixed concentration of caffeine, corresponding to the concentration of caffeine in a common cola beverage (0.67 mM) was added to the sweeteners and a non-caffeinated cola beverage. Subjects could distinguish between caffeinated and non-caffeinated sweeteners (p<0.001), but all subjects failed to distinguish between caffeinated and non-caffeinated cola beverage (p=1.0). Caffeine has no flavor activity in soft-drinks yet will induce a physiologic and psychologic desire to consume the drink.

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.