Biology 103
2003 Second Paper
On Serendip

As a sophomore in college, I know how important it is to get that first cup of coffee in the morning. That first cup of coffee, second cup, and third cup seem vital to the well-being of Bryn Mawr students all over campus. They help us to stay awake through our classes, hours of study, and even time spent socializing. But is caffeine really addictive? Ask any Bryn Mawr student, and chances are that she will answer with an emphatic "Yes!" Ask any scientist or doctor the same question and the answer is likely to be just as emphatic, but what that answer will be is much less predictable.

It is universally recognized that caffeine is a stimulant, a substance that causes the body to act differently from the ways that it would naturally act by inducing "fight or flight" reactions which cause the body to act in emergencies (1). However, it is still debated as to whether or not this stimulate is addictive. When deciding whether a substance is addictive, most professionals who make diagnoses in the United States and in many other countries will turn to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, better know as the DMS-IV. This manual is published by the American Psychiatric Association and lists, among other things, the symptoms of all mental health disorders. According to the DMS-IV, the symptoms of substance dependence (in other words, substance addiction) are substance abuse, continuation of use despite related problems, increase in tolerance, and withdrawal symptoms (2).

The debate lies largely in the interpretation of these symptoms. What exactly constitutes a withdrawal symptom? Can having a headache for a few days even compare to the horrors experienced by heroine addicts who suddenly stop drug intake? Are there problems related to caffeine intake? What exactly is meant by increase in tolerance?

It seems to me that all of these symptoms apply to people who have a regular intake of caffeine (e.g. coffee, tea, and cola drinkers) but to a much lesser extent than apply to people who are addicted to other substances such as prescription and illegal drugs. When a person who has been regularly consuming caffeine suddenly stops caffeine intake, that person is likely to experience symptoms such as irritability, inability to concentrate, constipation, and lethargy (1). A study in which people in a mental hospital were given either caffeinated or decaffeinated coffee produced results which indicated that caffeine is in fact addictive when those who were given decaffeinated coffee increased their coffee intake to consume the same amount of caffeine as they had with fully caffeinated coffee (3). These results show people exhibiting symptoms of substance dependency.

As for whether there is an increase in caffeine tolerance, Georges Koob, Ph.D., reasons that caffeine intake does not stimulate a craving for more caffeine because the tolerance is so complete that the same results are felt after relatively large amounts of caffeine as are felt after relatively small amounts, and this "discourages a chronic destructive pattern of abuse." This is also the case with the hallucinogen LSD (3). Some experts also say that even small doses of coffee can cause negative effects in the body, such as tiredness in the afternoon when the caffeine wears off (1), and it is generally recognized that high doses of caffeine (about the equivalent of eight cups of coffee or more) cause anxiety, excitability, restlessness, dizziness, irritability, loss of concentration, gastrointestinal aches, headaches, and trouble sleeping (4).

Many other experts claim that caffeine is not addictive. Again, the interpretation of tolerance seems to be where many of discrepancies lie. Herbert Muncie of the University of Maryland's family medicine department perceives tolerance as meaning that "you begin to need more and more, or a higher dosage of the chemical to experience the effects." He reasons that because this is not true in the instance of normal coffee intake, then caffeine must not be addictive (5). Especially controversial was a study conducted by Astrid Nehlig, Ph.D. of the National Health and Medical Research Institute in Strasbourg, France, in which animals consuming the equivalent of one to three cups of coffee a day did not exhibit withdrawal symptoms when caffeine intake was suddenly stopped (3).

Central to Nehlig's argument is that in her experiment, small doses of caffeine did not trigger functional activity in the shell of the nucleus accumbens (6), the part of the brain that is involved in reward and punishment (7) and is heavily involved in the addiction of other drugs such as amphetamines, cocaine, morphine, and nicotine (6). Nehlig did find, however, that the equivalent of seven or more cups of caffeinated consumed by these animals did trigger the activation in the nucleus accumbens (6). This last finding eludes to the probability that it possible to become addicted to caffeine. Technically, according to this study, caffeine in large doses is addictive. I am cautious, however, in blindly accepting the results of Nehlig's study. Caffeine might not act exactly the same way on animals as it does on humans. No matter how similar humans are to some other animals, there is no guarantee that our bodies would react the same way in any given situation.

Using the DMS-IV's definition of substance dependence, it seems to me that even small does of caffeine are in fact mildly addictive, even without the participation of the nucleus accumbens. Nowhere in the definition is the nucleus accumbens mentioned. Addiction can also be different to substance dependence. Perhaps caffeine is psychologically addictive in the same way that gambling is addictive.
Some experts are skeptical as to whether the negative effects felt by people who regularly consume caffeine can be considered to be "adverse". As Charles O'Brien, M.D. points out, linking caffeine addiction with addiction to serious illegal drugs could make serious drugs appear less dangerous than they really are (8). Although this might be an ethical issue, one should not refrain from calling caffeine addictive on the basis that it could influence children's decision to take illegal drugs. This is a matter that should concern parents and educators, not doctors and scientists.

In conclusion, it seems to me that small doses of caffeine are mildly addictive. Large doses are definitely addictive. However, I see little harm in becoming mildly addicted to this drug. The negative effects linked with this drug do not, in all cases, hinder normal functions of the body and mind. The reputable Mayo clinic even recommends drinking "a cup of coffee, tea, or a can of soda pop that contains caffeine" to people who have trouble staying awake at work (9). It should be up to the individual to determine how "adverse" these effects really are. If they are causing harm, one should make up one's own mind to stop or reduce caffeine intake. As far as long term effects of caffeine use, research has linked caffeine to osteoporosis, birth defects, miscarriages, infertility, cancers, high blood pressure, premenstrual syndrome, ulcers and heartburn, fibrocystic breast disease, and heart disease (4), however, these are ongoing studies and are beyond the scope of this report.

And now if you'll excuse me, I have a lot of homework and it looks like it's going to be a long night. I'm going to get myself a nice, steaming cup of coffee.

References

1)Today's Question, on DrWeil.com, a question and answer site about health and wellness.

2)AllPsych Online, a virtual psychology classroom.

3)Researcher Brews Debate About Whether Caffeine is Addictive, an article on the American Psychiatric Association Website.

4)Go Ask Alice!: Caffeine's effects on health, on the Go Ask Alice site, Columbia University's Health Question and Answer Internet Service.

5)Fix on this, coffee lovers: Caffeine may not be addictive, an article in the Diamondback, the University of Maryland's Independent Newspaper.

6)ScienceDaily News Release: Debate Brews over Caffeine Addiction – Study Also Confirms Caffeine Improves Alertness And Energy, on ScienceDaily, an online magazine.

7)nucleus accumbens, a short description of the nucleus accumbens on the Department of Integrated Science and Technology section of the James Madison University website.

8)Caffeine Myths and Facts, on koffeekorner.com, a coffee appreciation website

9)Sleepy at work? How you can stay awake, tips for staying awake at work on MayoClinic.com.


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