For those who love coffee, the taste is often cited as the reason for the "addiction" and the use of that word does not imply anything like a drug addiction. However, try to take away someone's coffee abruptly and chances are they will experience withdrawal symptoms (2). The body develops a dependence on caffeine which is very obvious; stop drinking coffee for a day after being a regular drinker and get a headache, then drink coffee and it goes away. Some call this an addiction, coining terms such as "caffeinisme" and "caffeine withdrawal syndrome" (4), and classify caffeine as a mind-altering drug (3) (5) (6) (7). Many others protect caffeine, saying it does not compare to a true drug addiction and some even claim it has benefits-that it not only increases alertness but has other healthful properties (2) (8) (9) (10) (11) (12) (13). It is very difficult to find an objective article on the effects of caffeine, for while the information is often corroborated by other reliable sources, one page will present all negative studies and side effects of the drug, and others only the positive. Reading a single article may convince you of one perspective, for there is a vast amount of information supporting both sides. Most agree that drinking caffinated beverages forms dependence, but those defending caffeine dismiss this as trivial while others see it as a very unhealthy cancer on society. The reality is somewhere in between. Caffeine is addictive but it is certainly not a strong physical addiction, for it is relatively easy to stop taking caffeine. The true addiction is psychological and is the most widespread addiction on earth.
The fact that caffeine is a drug cannot be denied. It effects the entire body in many ways, many involving chemical interactions in the central nervous system. One question is whether caffeine is even bad for you, if there is any reason to worry that one might be taking too much. The answer is that while providing many short-term benfits, caffeine has many short and long-term negative effects, which are and must be taken into consideration when deciding whether calling a craving for caffeine an addiction is justifiable.
Caffeine acts directly on the central nervous system as a mild stimulant (2). Once caffeine enters the blood stream, it takes only a few minutes for it to be all over the body. Only about 3% passes through and is released in urine. Most of its effects are short-term and are the ones everyone associates with it. The peak levels of caffeine in the blood are reached about 30 minutes after ingestion, and the half-life in the blood stream is about 4 hours (5). There are long-term effects which are less well-understood, such as possible carcenogenic properties and contribution to heart disease incidence (5).
The short-term effects include an increase in blood pressure (a health hazard for some) and elevate neural activity in many parts of the brain (5). The postponement of sleepiness that is the main effect attributed to caffeine, however it has many less-desired consequesnces as well. The alertness people crave is caused by caffeine's ability to block the binding sites for adenosine (14), a neurotransmitter which has a calming effect. It does this because it fits into the same receptors which accept adenosine and is even more attracted to these sites than the chemical intended to bind there. At the same time, the drug raises the level of other chemicals known to cause excitement, such as adrenaline, adrenal hormone cortisol, and lactate (6). These allow for faster reaction times and greater alertness.
Many of the negative side effects of caffeine are also related to its effects on the nervous system. When a person has too much caffeine, that amount depending on the person's ability to metabolize caffeine, restlessness, jitteriness, dehydration, and arrythmias can result (4). The inability to sleep when sleep is desired can be considered a negative side effect, and the quality of sleep in which caffeine is still effecting the body is lowered. Less time is spent in REM sleep, when dreaming occurs and which is the most essential part of sleep to humans, so the person will often feel less refreshed in the morning (5). A feeling of nervousness can also result, probably caused by the faster heart rate and increased levels of stimulating chemicals released in the nervous system.
Now that caffeine is recognized as a substance that is not ingested without consequences, the question becomes whether the need for caffeine can be called an addiction (2). The answer to this seems to depend on one's definition of "addiction". In popular usage, many would say that they are "addicted" to coffee or to caffeine simply because they have it every day and don't want to go without it. Psychologists and others who deal with addiction as an illness define an addict as having "1) severe withdrawal symptoms; 2) tolerance to a given dose, or the need for more and more of the substance; 3) the loss of control, or the need to consume the substance at all costs"(13). Most agree that the term caffeine "dependence" is more acceptable. This is partly because of a wish to preserve the seriousness of the term addiction for drugs and alcohol which are more harmful, since many feel that if the term addiction is overused and people overreact to the "threats" posed by caffeine, kids will take warnings about other drugsless seriously (1).
"Caffeine dependence syndrome" has been observed by Strain et al. of Johns Hopkins University, however the reliability of the study has been called into question because of the small number of participants and the fact that they were not randomly chosen. The participants were self-described as dependent on caffeine, making it questionable whether the study applies to the general population (1) (13). Many other studies using lab animals are also mistrusted because of conflicting data among nearly identical studies. Many other studies are mistrusted because of the difference in metabolism of caffeine between humans and animals, and the body's reaction to caffeine is not well understood in other organisms and so cannot necessarily be said to give information on humans (15).
Caffeine dependence, while the term is watered-down, is really a weaker kind of addiction, because it features to a lesser extent the 3 aspects of addiction described above. It has withdrawal symptoms that are not always severe, but can be more intense and last up to 48 hours (3). Some articles describe the headaches associated with withdrawal as "mild" (13) but they can actually be more like a migraine in intensity according to many who have gone through withdrawal. Withdrawal symptoms in the morning can make it more difficult for a caffeine-dependent person an equivalent to a hangover where they are essentially useless until they get their morning coffee or tea (6). Caffeine perpetuates its own use by curing its own side effects, much like alcohol. When one is tired from not having had enough REM sleep due to too much caffeine, caffeine is a convenient way to wake up. If withdrawal headaches manifest themselves, caffeine will cure it immediately. In fact many headache medicines include caffeine, partially because caffeine improves the activity of analgesics but also because if the headache is cause by caffeine, the added dose of caffeine will alleviate it (8).
Once a certain level of caffeine consumption is reached, and the person is dependent, they will also develop a tolerance to caffeine. Those who drink large amounts can become immune to the effects of all but the largest doses of caffeine while people who use it infrequently often feel effected by as little as 1 cup of coffee (3). This means that people who use coffee to feel energetic will have to take more, thereby filling the second requirement of an addiction. There is not a realistic comparison of caffeine dependence to hard drug dependence as far the third point is concerned. While some might go out of their way to buy coffee, no one would go to extreme measures such as theft to support a "habit."
Most people, however, would not have trouble quitting if only the physiological consequences applied. A headache for a couple of days and possibly anxiety, rebound drowsiness, fatigue or lethargy and various other problems, is not really too bad and most people could handle it (4). It is also not likely that a person will get "hooked" on caffeine after finally kicking the habit by relapsing and drinking a cup of coffee because it will not cause dependence unless a certain amount is taken regularly. Most people have a psychological dependence on the drug that makes them feel that the benefits far outweigh any possible negative aspects of taking caffeine. People feel energized and their mental and manual acuity are often increased (9). Athletes take caffeine to increase stamina and performance (3), and runners will take it to have a faster starting time (16).
The increased performance along with the denial of danger makes the person who avoids caffeine a rare specimen. Many feel that they would not be able to do everything that they needed to do if they could not have caffeine (17). The American work ethic often makes people to feel that they must achieve as much as possible and that the more they achieve, the better they are, and caffeine allows them to be more productive. It allows them to stay awake when they might otherwise fall asleep out of sheer exhaustion.
There is great need for more research regarding the properties of caffeine. There is too much contradictory information and studies are not conclusive. A huge number of people around the world consume enough caffeine to be diagnosed as dependent who have not been reassured that it is safe. Nor have they been given a good enough reason to stop their consumption or cut down to safer levels of caffeine intake. It would take a lot of negative findings to dissuade people from using the drug, but a better understanding on all properties could also find more uses for caffeine and could reassure those who are doubtful of the safety of caffeine consumption.
3)How Caffeine May Impact Performance
4)What is Caffeine?
5)Why is abuse of this drug a problem?
6)America's Favorite Drug, by Michael Traub, N.D.
7)Caffeine Detoxification, by Elson M. Haas, M.D.
8)Short Term Effects
9)Caffeine and Your Health
10)What's the scoop on caffeine and your health?, by Debbie Donovan
11)Can caffeine control asthma?, by Melvyn R. Werbach, M.D.
12)Caffeine and Addiction
14)Myths and Facts about Caffeine
15)Caffeine Jitters: Some Safety Questions Remain, by Chris W. Lecos
16)Effects of Caffeine on Female Athletes Studies , by Sophie Wilson
17)Safety Limits for Caffeine
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This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.