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One Addict’s Story (part 3)

Published: July 6, 2010

In our last installment we explored a recent study done to test caffeine’s ability to wake us from our nightly slumber, and were shown that caffeine might not have the same alerting effects that we “addicts” might think. As I explored this study and the conclusions it drew, I noticed something interesting. The results of this study showed a strong resemblance to the opponent-process model of addiction. The opponent-process model says that people become addicted to a drug because of a change in their hedonic set point, or their normal level of “feeling good”. Basically, when someone does a drug, they feel better than normal, but when they come down off the drug they feel slightly worse than normal. With each subsequent use, the total “high” decreases and the “low” worsens, until users are using so that they can achieve a sense of normalcy. This hedonic response seems analogous to the alertness from using caffeine, and the need for habitual caffeine users to drink their daily cup of coffee in order to achieve a normal state of awareness seems to fit the opponent-process model of addiction. Don’t get me wrong, I am not arguing with the experts in this matter, I am not going to enter into the debate of whether caffeine use can be an addiction, or what the definition of addiction is. What I am stating, however, is that the nature of caffeine use, its alerting effects, and the strong headaches that are associated with an absence of caffeine in habitual users, show that caffeine does induce a withdrawal symptom.

The caffeine withdrawal syndrome:

Withdrawal syndromes are simply clinical syndromes which develop after the cessation of habitual substance use. Alcohol, opiates, and nicotine all have their own withdrawal syndromes, each with symptoms specific to the drug in question. Caffeine’s withdrawal syndrome can be characterized by headache, fatigue, drowsiness, irritability, depression, anxiety, and impaired cognitive and psychomotor abilities. With so many negative physical and mental effects associated with caffeine withdrawal, it becomes much easier to understand why Starbucks can charge $6.50 for a latte and still manage to attract customers. Starbucks, like Budweiser and Phillip Morris, have it good. They are able to sell products that have been clinically proven to have negative consequences for those people who stop using the drugs which they sell. Crack dealers fantasize about that type of legitimacy.

As I sit here and compare Starbucks to a crack dealer, I can’t help but notice the nearly empty mug of cold coffee not six inches from my keyboard. I can’t help but notice the mug full of fresh coffee in my hand. As I sip away at my third cup of coffee today, I start to wonder, as I am sure many do, are the dependence and withdrawal effects of caffeine dangerous?

For fun, let us first approach this question with a bit of cellular physiology. Way back in part one, I presented the theory of caffeine affecting parts of the adenosine system in our brains. If you remember, it was adenosine that had been shown to induce drowsiness in cats, and thus hypothesized (and I can’t stress that word enough) that it would have the same effect in humans. In our brains, we have neurotransmitters, chemicals which act as messengers between our brain cells. When brain cells want to talk to one another, they release these neurotransmitters, which act as tiny keys, searching for the appropriate lock, or receptor protein, on the neighboring brain cell. When the key finds the proper lock, the door opens and the cells can communicate (in a g-protein regulated secondary messenger cascade manner of speaking). In the case of adenosine and cats, the adenosine key is released when one brain cell gets sleepy. Adenosine receptors on neighboring cells are then able to unlock and the sleepy brain cell can tell the other brain cells, like the ones controlling our muscles, that it is time to take a break. Now enter caffeine. Caffeine has a structure reminiscent of adenosine, and like a similarly shaped key will actually fit into the adenosine receptor lock. Just like that similarly shaped key, caffeine won’t actually open the door for cellular communication, but it does block the proper key, adenosine, from getting into the lock. Essentially what happens is that one brain cell is trying to tell the others that it is time to go to sleep, but the caffeine is blocking that communication, so we are able to keep working, studying or partying without dozing off.

Part of the definition of what it means to actually be alive, is the ability to maintain homeostasis. Homeostasis is the ability of an organism to maintain a constant state when presented with environmental challenges. For example, when we get hot, we tend to sweat. The sweat allows for evaporative cooling, and we can maintain a rather consistent body temperature, thus maintaining homeostasis. The same thing occurs when we put drugs into our bodies. A habitual user of caffeine will have blocked enough adenosine receptor proteins that our bodies will compensate to maintain homeostasis. This can be done by either releasing more adenosine transmitter, or creating more adenosine receptors. Eventually, despite all of the caffeine intake, more locks and more keys will allow proper communication between cells. This internal maintenance of homeostasis is also the mechanism of tolerance to caffeine and its effects. So when a habitual user of caffeine stops using, their brains actually have more adenosine transmitter and receptors than normal, and without the caffeine to block some of the receptors, we experience excessive drowsiness and fatigue. Eventually, should a person abstain from caffeine for a long enough period of time, our bodies will again adjust in an effort to maintain homeostasis, and the caffeine withdrawal symptoms will subside.

It would seem that, while unpleasant, the fatigue and drowsiness of caffeine withdrawal is physically harmless. Psychologically and socially, however, caffeine withdrawal may be devastating. Studies done in 2003 showed that while some habitual caffeine users show no functional impairment upon withdrawal, others have an extremely difficult time performing their daily routines, some even missing work or neglecting their responsibilities with their children. There wasn’t a large correlation between the daily use of caffeine and the severity to which one reneged on their social duties, indicating that the caffeine withdrawal syndrome is highly individual. So while undergoing a withdrawal from caffeine will most likely not kill you, it very well might have a significant impact of your social, professional, or family life.

Another widely recognized symptom of caffeine withdrawal is a severe headache. This, when combined with the fatigue caused by a hyperactive adenosine sleep-messenger system, might be the cause of all of the irritability associated with caffeine withdrawal. Look forward to an exploration of this topic, and perhaps an answer to the question of what you should be doing about all of this, as we conclude the topic of caffeine in part 4.