Effect of Caffeine on Adolescent Psychological and Physiological Health

Caffeine is the world’s most popular drug, with 90% of adult North Americans consuming it daily[1]. Furthermore, adolescents are the fastest growing population of caffeine consumers, with a study by Brazier indicating 83.2% of teenagers consume caffeinated beverages regularly[2]. Caffeine is classed as a psychoactive stimulant, however unlike the majority of other stimulants, it is both legal and rarely regulated in most countries. The prominence and variety of energy drinks (refer to Figure 1), in the last two decades, has spawned an argument on whether caffeine should have increased regulations[3]. By drawing on a range of primary and secondary evidence, including interviews with medical professionals, medical journals, surveys of school students, governmental websites and sporting articles, this report will analyse the psychological and physiological effects of caffeine on adolescents, making an observation on whether the drug is more beneficial than harmful, and if regulations on the drug should be increased. As a widely accessible stimulant, caffeine is consumed to increase alertness, often to remove feelings of drowsiness. However, excessive consumption of caffeine can lead to detrimental effects to the consumer. Therefore, depending on the quantity of caffeine consumed, as well as the caffeine tolerance of the consumer, the effects can be either beneficial or harmful.

Figure 1: Variety of Caffeinated Products

Source: Stuff.co (2019)

Caffeine and athletic performance

Caffeine is commonly consumed with the belief that it will enhance athletic performance to a significant degree. A study by de Souza Gonçalves indicates that performance can be enhanced through acute caffeine consumption[4]. This ergogenic property of caffeine consumption has contributed to perception of performance[5]. As in a study by Duncan discussing caffeinated energy drinks effect on various psychological measures during submaximal cycling, it was found that pain and exertion perception decreased when consuming caffeine pre-exercise[6]. Furthermore, the study found the long-standing paradigm that habitual caffeine consumption will influence caffeine supplementation’s ergogenic properties to be false. As low, moderate and high caffeine consumers, after acute caffeine supplementation of 6mg/kg body weight, showed similar improvements in cycling time trial performance[7]. In terms of category of exercise, a higher level of performance is seen in endurance exercises, rather than with shorter exercises (8-20 minutes), and a negligible level of performance improvement seen in sprint exercises (refer to Figure 2).

Figure 2: Effect of Caffeine on Performance

Source: Vox.com (2019)

There appears to be a limit to the ergogenic effects of caffeine supplementation, as seen in a study by Hunter discussing caffeine ingestion effect on a 100-km cycling time trial performance, no improvement was observed[8]. For increased performance, an adolescent, elite athlete can consume caffeine for the ergogenic effects, however caffeine consumption could also prove detrimental to performance and the athlete’s body health. Consuming caffeine before exercise, may lead to nausea, or caffeine jitters, which proves even more detrimental to already anxious young athletes[9]. Caffeine consumption can coincide with high calorie intake, as caffeinated products usually contain high levels of sugar[10]. This, therefore, could detrimentally impact an athlete’s body health, which in turn could make it more difficult to maintain fitness and muscle mass.

Caffeine and sleep quality

Caffeine as a stimulant increases alertness, however this can detrimentally impact the sleep of adolescents. A study by Faris discussing the effect of energy drinks on sleep quality of college students found a significant correlation between energy drink consumption and sleep quality, sleep patterns and bedtime. It is important to note that no sign of a significant association between energy drink consumption and amount of time asleep was observed[11]. Adolescents are especially susceptible to being detrimentally affected by a lack of sleep quality due to caffeine, as a hormonal shift during puberty shifts their body clock forward 1-2 hours, meaning on average they get to sleep later[12]. However, due to early school starts they are unable to get the prescribed 8-10 hours of sleep, which when combined with a lack of sleep quality can lead to chronic sleep deprivation[13]. The effects of chronic sleep deprivation can include concentration difficulties, memory impairment, poor decision making, moodiness and aggression, as well as both reduced academic and sporting performance[14]. This is further supported in a study by Gaultney focusing on the relationship between sleep disorders and academic achievement among college students, which indicated sleeping disorders led to academic difficulties[15]. In a survey of a schooling body (refer to Figure 3), 25% of respondents confirmed consuming caffeine after 9pm, showing a significant number of adolescents consuming the stimulant before attempting to sleep[16].

Figure 3: Results of Caffeine Survey

Source: SurveyMonkey (2019)

All these factors can have a significant detrimental psychological effect on adolescents, especially when suffering from a variety of the effects simultaneously, leading to a dangerous cycle of dependency. By relying on caffeine consumption to stay alert and awake, especially when completing academic assignments, the overall social and academic life of a student will suffer, but they will continue to consume caffeine as they cannot function properly without it[17]. In a documentary analysing dependency on caffeine in college students, students interviewed indicated they initially consumed caffeine to cope with stress, but were now unable to function without it[18].

Caffeine and Depression

A recent debate within the medical community, is whether caffeine consumption has a positive or negative effect on instances of depression. A medical study by Strachan on the relationship between caffeine and depression, found that caffeine consumption decreases incidences of depression[19]. This is further supported by a study by Navarro which found that there was not a dose-response association between caffeine consumption and incidents of depression[20]. In this, participants who drank larger quantities of coffee (4 cups of coffee per day), showed a significantly lower risk of depression than those who drank up to or less than one cup of coffee[21]. The results show that beyond having a negligible effect on instance of depression, caffeine consumption may actually lead to a decrease in instances of depression, therefore improving overall mental health. Coffee was seen to be the most effective in lowering the risk of depression, as beyond just the caffeine component, the other elements of coffee including chlorogenic acid, ferulic acid, and caffeic acid, have been shown to also help reduce the risk of depression[22], as they can reduce the inflammation of nerve cells in the brains of depression sufferers[23]. Another study by Grosso, and a separate study by Wang, collaborate this finding, showing a significant correlation between caffeine, and especially coffee, in a decrease risk of depression[24] [25]. However, some studies show a linkage between excessive caffeine intake and increased risk of depression[26], the main cause of this being excessive caffeine consumption resulting in levels of anxiety, which in turn progresses into depression[27]. Due to this, it’s important to follow the recommended daily intake for your body weight, for the average adult being 500m/g per day of caffeine[28], as excessive consumption may prove harmful to mental health, increasing incidences of depression. 

Energy drinks

The increasing popularity of energy drinks in the past decade, has led to a debate on how dangerous they can be towards consumers[29]. The risk from energy drink consumption comes from the high quantities of caffeine present (refer to Figure 4), combined with the ability to scull drinks at a fast pace. This enables people, especially adolescents, to quickly drink in excess of the recommended caffeine daily intake amount[30].

Figure 4: Caffeine Serving Quantities

Source: Pinterest (2019)

In the U.S, emergency visits to hospital due to excessive energy drink consumption doubled from 2007, around 10,000, to over 20,000, by 2011[31]. In Australia, Associate Professor Naren Gunja checked similar trends and found that over a five-year period, there was a fivefold increase in the number of people who called a poison centre annually who were suffering from adverse side-effects of energy drinks[32]. Caffeine and sugar were the primary cause of such calls, with symptoms ranging from chest pain or mild palpitations and tremors, anxiety, seizures, heart attack, and cardiac arrhythmias[33]. The average age of the callers was only 17, and around half needed hospitalisation[34]. The main issue is binge drinking at parties and nightclubs, especially when combined with alcohol and drugs, furthermore another issue is excess consumption at amateur and school athletics in order to try and gain a competitive edge[35]. Government regulating bodies, around the world, are concerned with the risks of energy drink consumption, and after reported fatal incidents following energy drink consumption, Norway and Denmark banned the drinks from regular sale in stores[36]. In these countries, they are now classified as medicines due to high caffeine content, and only sold in pharmacies[37]. As a result of this, in these countries, it’s much more difficult for adolescents to abuse these products, and therefore are at less risk of suffering from the extreme side-effects of caffeine.

Dangers of caffeine

The European Food Safety Authority recommended a maximum caffeine daily intake of 3mg/per kg of body weight for adolescents and children[38]. Gender does not affect this recommended daily intake, as the guidelines are founded on weight, not gender-based[39], but as the average adolescent female (53.5kg at 16 years old) weighs less than an average adolescent boy (60.8kg at 16 years old)[40], they are still at an increased risk of overdosing on caffeine. However, caffeine tolerance can differ depending on genetic differences in the ability to breakdown caffeine[41]. Caffeine intoxication occurs when the recommended intake is exceeded, the effects of which include palpitations, tremors, agitation, and gastrointestinal upset; but these effects stop once caffeine consumption is halted or reduced[42]. Excessive caffeine consumption can cause seizures, heart arrythmias, and increased blood pressure; all of which could be life threatening to both adults and adolescents[43]. refer

Figure 5: Physiological Effects of Caffeine

Source: TeaGuardian.com (2019)

However, the risk of caffeine consumption leading to a fatal incident from intoxication, is highly unlikely, as over 1 gram of caffeine has to be consumed to be at high risk[44]. Dr. Ian Musgrave reports seeing one case of a young woman dying through caffeine intoxication, the woman had a pre-existing heart disease, and had consumed 15-20 cups of coffee (approximately 1 gram of caffeine)[45]. People with pre-existing heart conditions are at greater risk when consuming caffeine, especially as adolescents may have undiagnosed heart conditions, furthermore viral infection can cause heart problems, which high caffeine intake may exacerbate[46]. These results indicate caffeine consumption poses a negligible risk to the consumer, unless suffering from a pre-existing heart condition, or consumed beyond the recommended daily amount.

Conclusion

The weight of this evidence would suggest caffeine consumption has a significant impact on the physiological and psychological health of adolescents, specifically when consumed in excess of recommended guidelines. In regard to physiological effects, caffeine supplementation can enhance an adolescent athlete’s performance, however the unhealthy nature of caffeinated products could prove detrimental to overall fitness. Furthermore, excess caffeine consumption, beyond the recommended intake, will lead adolescents to experience a range of side-effects, all of which can be harmful, or possibly fatal. In regard to psychological effects, caffeine has shown to possibly decrease instances of depression, when consuming in quantities recommended by the European Food Safety Authority. However, excessive caffeine consumption can result in anxiety, which ultimately, can lead to depression. Furthermore, caffeine’s negative effect on sleep quality can also prove detrimental to an adolescent’s social and academic life, which also could prove harmful to their overall wellbeing. Overall, the data suggests caffeine consumption to be safe for adolescents without heart conditions, but only when consumed within the recommended daily intake amount. Excessive caffeine consumption, beyond these guidelines, can be dangerous to an adolescent’s physical and mental health. Therefore, it is suggested that adolescents avoid the consumption of energy drinks, and other highly caffeinated substances, through both increased regulations by government bodies, and monitoring by legal guardians, to prevent late-night consumption or regular excess consumption.

References:

• ‘Energy Drinks’ 2013, BTN, ABC, SA, 17 September, ABC.net.
• ‘Energy Drinks’ 2013, Catalyst, ABC, Sydney, 15 August, ClickView. 
• Better Health Channel 2018, Caffeine, Victorian State Government, Victoria, viewed 28 May 2019, <https://www.betterhealth.vic.gov.au/health/healthyliving/caffeine>.
• Brazier, Y 2016, ‘Adolescents drink too much caffeine’, MedicalNewsToday, 8 March, viewed 25 August 2019, <https://www.medicalnewstoday.com/articles/307526.php>.
• Clark, N n.d., The facts about caffeine and athletic performance, Active, viewed 11 June 2019, <https://www.active.com/articles/the-facts-about-caffeine-and-athletic-performance>.
• de Souza Gonçalves, L 2017, ‘Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation’, Journal of Applied Physiology, 18 July, viewed 18 August 2019, <https://www.physiology.org/doi/full/10.1152/japplphysiol.00260.2017>.
• Disabled World 2017, Average Height to Weight Chart – Babies to Teenagers, viewed 18 August 2019, <https://www.disabled-world.com/calculators-charts/height-weight-teens.php>.
• Duncan, M 2013, ‘The effect of a caffeinated energy drink on various psychological measures during submaximal cycling.’, PubMed, 27 May, viewed 18 August 2019, <https://www.ncbi.nlm.nih.gov/pubmed/23542532>.
• Faris, M, Jahrami, H & Al-Hilali, M 2016, Energy drink consumption is associated with reduced sleep quality among college students: a cross-sectional study, ResearchGate, pdf, viewed 12 June 2019, <https://www.researchgate.net/publication/303892745_Energy_drink_consumption_is_associated_with_reduced_ sleep_quality_among_college_students_a_cross-sectional_study_Energy_drinks_affect_sleep_quality_among_college_students>.
• Grosso, G 2015, ‘Coffee, tea, caffeine and risk of depression: A systematic review and dose–response meta‐analysis of observational studies’, Molecular Nutrition Food Research, 19 August, viewed 18 August 2019, <https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201500620>.
• Hall, S 2015, ‘A review of the bioactivity of coffee, caffeine and key coffee constituents on inflammatory responses linked to depression’, MedicalNewsToday, vol. 76, viewed 18 August 2019, <https://www.sciencedirect.com/science/article/pii/S0963996915301174>.
• Hunter, A 2002, ‘Caffeine ingestion does not alter performance during a 100-km cycling time-trial performance.’, PubMed, 12 December, viewed 18 August 2019, <https://www.ncbi.nlm.nih.gov/pubmed/23542532>.
• Knapp, S 2015, ‘Anxiety Can Lead to Depression, and Depression Repays the Favor’, HuffPost, 21 January, viewed 18 August 2019, <https://www.huffpost.com/entry/anxiety-leads-to-depressi_b_6165906?guccounter=1>.
• Lee, C 2017, ‘The Science Behind the World’s Most Popular Drug’, Office for Science and Society, 18 September, viewed 18 August 2019, <https://www.mcgill.ca/oss/article/infographics-general-science/science-behind-worlds-most-popular-drug>.
• Lennon, D 2019, Effects of Caffeine Consumption on Adolescents, survey, SurveyMonkey, 5 May, viewed 17 June 2019, <https://www.surveymonkey.com/r/6XCP63K>.
• Musgrave, I 2019, pers. comm., 4 July.
• Navarro, A, Abasheva, D & Martínez-González, M 2018, ‘Coffee Consumption and the Risk of Depression in a Middle-Aged Cohort: The SUN Project.’, PubMed, p. 1, viewed 28 May 2019, National Center for Biotechnology Information, EBSCOhost.
• Ramussen, K 2012, Awake Documentary, online video, 2 April, viewed 18 August 2019, <https://www.youtube.com/watch?v=dxPMgTPfzT0>.
• Strachan, G 2019, ‘What effect does caffeine have on depression?’, MedicalNewsToday, 19 August, viewed 18 August 2019, <https://www.medicalnewstoday.com/articles/313988.php>.
• Wang, L 2015, ‘Coffee and caffeine consumption and depression: A meta-analysis of observational studies’, Australian and New Zealand Journal of Psychiatry, 2 September, viewed 18 August 2019, <https://journals.sagepub.com/doi/abs/10.1177/0004867415603131>.
• Willoughby, S 2019, pers. comm., 15 July.

[1] Lee, C 2017, ‘The Science Behind the World’s Most Popular Drug’, Office for Science and Society, 18 September, viewed 18 August 2019, <https://www.mcgill.ca/oss/article/infographics-general-science/science-behind-worlds-most-popular-drug>.

[2] Brazier, Y 2016, ‘Adolescents drink too much caffeine’, MedicalNewsToday, 8 March, viewed 25 August 2019, <https://www.medicalnewstoday.com/articles/307526.php>.

[3] ‘Energy Drinks’ 2013, BTN, ABC, SA, 17 September, ABC.net.

[4] de Souza Gonçalves, L 2017, ‘Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation’, Journal of Applied Physiology, 18 July, viewed 18 August 2019, <https://www.physiology.org/doi/full/10.1152/japplphysiol.00260.2017>.

[5] Duncan, M 2013, ‘The effect of a caffeinated energy drink on various psychological measures during submaximal cycling.’, PubMed, 27 May, viewed 18 August 2019, <https://www.ncbi.nlm.nih.gov/pubmed/23542532>.

[6] ibid

[7] de Souza Gonçalves, L 2017

[8] Hunter, A 2002, ‘Caffeine ingestion does not alter performance during a 100-km cycling time-trial performance.’, PubMed, 12 December, viewed 18 August 2019, <https://www.ncbi.nlm.nih.gov/pubmed/23542532>.

[9] Clark, N n.d., The facts about caffeine and athletic performance, Active, viewed 11 June 2019, <https://www.active.com/articles/the-facts-about-caffeine-and-athletic-performance>.

[10] ibid

[11]Faris, M, Jahrami, H & Al-Hilali, M 2016, Energy drink consumption is associated with reduced sleep quality among college students: a cross-sectional study, ResearchGate, pdf, viewed 12 June 2019, <https://www.researchgate.net/publication/303892745_Energy_drink_consumption_is_associated_with_reduced_sleep_quality_among_college_students_a_cross-sectional_study_Energy_drinks_affect_sleep_quality_among_college_students>.

[12] Better Health Channel 2018, Caffeine, Victorian State Government, Victoria, viewed 28 May 2019, <https://www.betterhealth.vic.gov.au/health/healthyliving/caffeine>.

[13] ibid

[14] ibid

[15]Faris, M, Jahrami, H & Al-Hilali, M 2016

[16] Lennon, D 2019, Effects of Caffeine Consumption on Adolescents, survey, SurveyMonkey, 5 May, viewed 17 June 2019, <https://www.surveymonkey.com/r/6XCP63K>.

[17] Ramussen, K 2012, Awake Documentary, online video, 2 April, viewed 18 August 2019, <https://www.youtube.com/watch?v=dxPMgTPfzT0>.

[18] ibid

[19] Strachan, G 2019, ‘What effect does caffeine have on depression?’, MedicalNewsToday, 19 August, viewed 18 August 2019, <https://www.medicalnewstoday.com/articles/313988.php>.

[20] Navarro, A, Abasheva, D & Martínez-González, M 2018, ‘Coffee Consumption and the Risk of Depression in a Middle-Aged Cohort: The SUN Project.’, PubMed, p. 1, viewed 28 May 2019, National Center for Biotechnology Information, EBSCOhost.

[21] Navarro, A, Abasheva, D & Martínez-González, M 2018,

[22] Strachan, G 2019

[23] Hall, S 2015, ‘A review of the bioactivity of coffee, caffeine and key coffee constituents on inflammatory responses linked to depression’, MedicalNewsToday, vol. 76, viewed 18 August 2019, <https://www.sciencedirect.com/science/article/pii/S0963996915301174>.

[24] Grosso, G 2015, ‘Coffee, tea, caffeine and risk of depression: A systematic review and dose–response meta‐analysis of observational studies’, Molecular Nutrition Food Research, 19 August, viewed 18 August 2019, <https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201500620>.

[25] Wang, L 2015, ‘Coffee and caffeine consumption and depression: A meta-analysis of observational studies’, Australian and New Zealand Journal of Psychiatry, 2 September, viewed 18 August 2019, <https://journals.sagepub.com/doi/abs/10.1177/0004867415603131>.

[26] Strachan, G 2019

[27] Knapp, S 2015, ‘Anxiety Can Lead to Depression, and Depression Repays the Favor’, HuffPost, 21 January, viewed 18 August 2019, <https://www.huffpost.com/entry/anxiety-leads-to-depressi_b_6165906?guccounter=1>.

[28] Musgrave, I 2019, pers. comm., 4 July.

[29] ‘Energy Drinks’ 2013, BTN, ABC, SA, 17 September, ABC.net.

[30] ‘Energy Drinks’ 2013, Catalyst, ABC, Sydney, 15 August, ClickView. 

[31] ibid

[32] ibid

[33] Willoughby, S 2019, pers. comm., 15 July.

[34] ‘Energy Drinks’ 2013, Catalyst, ABC, Sydney, 15 August, ClickView. 

[35] Musgrave, I 2019, pers. comm., 4 July.

[36] Willoughby, S 2019, pers. comm., 15 July.

[37] ibid

[38] Musgrave, I 2019, pers. comm., 4 July.

[39] ibid

[40] Disabled World 2017, Average Height to Weight Chart – Babies to Teenagers, viewed 18 August 2019, <https://www.disabled-world.com/calculators-charts/height-weight-teens.php>.

[41] Musgrave, I 2019, pers. comm., 4 July.

[42] ibid

[43] Willoughby, S 2019, pers. comm., 15 July.

[44] Musgrave, I 2019, pers. comm., 4 July.

[45] ibid

[46] ibid