In the Feb/March 2019 issue of Free Inquiry magazine, there was an article by John Frantz, MD, titled “The Biology of Addiction”. The title is a misnomer. Rather than covering the biology of addiction, he speculated about one possible explanation for why addiction might have evolved, and then told a series of anecdotes about headache as a withdrawal symptom of caffeine addiction. The article was unfortunate. He’s entitled to his own opinions, but not to his own facts. In the first place, there’s no such thing as caffeine addiction.
Evolutionary explanations of addiction
He speculates that addiction might have been a survival advantage because addicts can develop a tolerance to high doses of the substances they are addicted to. He says,
Imagine vegetarian animals surviving a drought because they become tolerant of toxic chemicals in a plant that is also surviving the drought.
He points out that opium plants have edible components. But are they drought-resistant? Are they likely to be the only available food source? Could an animal get enough nutrition from them without dying of an overdose of opioids?
That’s pretty far-fetched speculation. It doesn’t make sense to me. And evolutionary biologists have explored the evolutionary origins and significance of addiction in the light of biological, psychological and social factors. Psychotropic plants and human brains may have influenced each other’s evolution. The plants may indeed be used as food sources, but withdrawal is inevitable. Speculating about emotion, fitness, reward systems, and social factors, Tammy Saah said, “Regardless of the possible co-evolution of drugs and mammalian brains, abuse of drugs inevitably causes long-term disadvantages.”
Another commenter said, “I think that addiction is a byproduct (a nasty one, quite often) of having a brain designed to maximize goal-pursuit in an uncertain world.”
In yet another evolutionary model, acting on pleasurable desires was once adaptive, but now we have pleasurable substances that will kill us, and we have not had time to adapt to the availability of addictive substances.
Dr. Frantz offers one, and only one, speculation about the evolutionary advantages of addiction. He seems to assume that evolution only proceeds by adaptive selection, for survival advantage; but sometimes evolution produces accidental byproducts or spandrels, as Stephen Jay Gould called them, characteristics that were not selected for but just came along for the ride. And pure chance can create characteristics that are neither beneficial nor harmful; and they can persist because they are irrelevant.
However you look at it, the evolution of addiction is complicated, and has been looked at in depth by experts. It is not a question likely to be solved by one newcomer who invents his own idea and doesn’t even acknowledge the work of others.
Caffeine is not addictive
Dr. Frantz starts by saying we are prone to becoming addicted to substances. He mentions alcohol and cocaine, but says “Caffeine is our primary example.” That’s a mistake; caffeine is not addictive in the strict sense of the word.
People can be addicted to opioids, cocaine, amphetamines, nicotine, and alcohol; but can they be addicted to caffeine? Lots of people think so. There are plenty of testimonials, for instance “How one cup of tea per day turned me into a caffeine addict.” The main reason they believe it is addictive is that they experience withdrawal symptoms, especially headaches. They confuse dependence with addiction. Regular coffee drinking results in mild physical dependence but addiction is a pathological and compulsive form of use. Some sources say caffeine addiction is real, but they define addiction as excessive use and relying on it to cope with life in spite of negative effects. The word “addiction” is used even more loosely in common conversation (“I’m addicted to cooking shows.”) True caffeine addiction has never been documented in humans. A review of the literature found that caffeine does not meet either the common-sense or the scientific definition of an addictive substance. Caffeine use disorder and caffeine withdrawal are listed in the DSM 5, but caffeine addiction is not.
Regular coffee drinking leads to tolerance. Tolerance is a pharmacological concept where patients have a reduced response to a drug following repeated use, and have to increase the dose. It is common with addictive drugs but can occur with non-addictive drugs too.
Addiction is defined as a chronic, relapsing disorder characterized by compulsive drug seeking and use despite adverse consequences. It is considered a brain disorder, because it involves functional changes to brain circuits involved in reward, stress, and self-control, and those changes may last a long time after a person has stopped taking drugs.
Withdrawal from coffee can cause symptoms like headache, fatigue, anxiety, irritability, depressed mood, and difficulty concentrating. Caffeine withdrawal has been recognized as a disorder. Withdrawal symptoms begin 12-24 hours after cessation, peak in 20-48 hours and have been reported to last as long as 7-12 days. Many sources report severe, intense caffeine withdrawal headaches. But 50% of habitual coffee drinkers will not experience any withdrawal symptoms. I am one of that lucky half. I have abruptly stopped my usual 5 cups a day and had no withdrawal symptoms whatsoever. I found that I was not craving coffee, but I missed the comfort of having that cup of hot liquid to sip on. I found that other hot beverages were just as satisfying (hot lemonade, bouillon, etc.).
Alternative medicine has chimed in. Predictably, dietary supplements and essential oils have been recommended to treat withdrawal symptoms; their effectiveness has not been scientifically tested. But it makes more sense to prevent withdrawal symptoms than to treat them: gradually reducing consumption is proven to work. When avoiding caffeine, it’s important to remember that it’s not just in coffee. There is caffeine in tea, cocoa, chocolate, soft drinks, energy drinks, pain medications, diet pills, and there is even a small amount in decaffeinated coffee.
Coffee is good for you
Frantz’s article is very one-sided. It provides many anecdotes of caffeine withdrawal headaches, makes them sound terrible, and makes it sound like everyone will get them. He says if he drinks one cup of coffee a day for lunch and then skips a day, he will develop a headache at 4 pm that day. He calls it tachyphylaxis. I wonder if it might just be suggestion. He fails to mention that half of caffeine users will never have any withdrawal symptoms.
Coffee has many health benefits. It has been linked to reduced risks of diabetes, cirrhosis, colorectal cancer, heart disease and stroke, Alzheimer’s and Parkinson’s disease, and even a longer lifespan. Numerous studies have shown that coffee is the biggest dietary source of antioxidants. Coffee has a mild diuretic effect, but the water in coffee replaces what is lost in the urine, so it doesn’t cause dehydration. There are no significant health risks unless you drink excessive amounts.
Conclusion: Caffeine is not addictive
Coffee drinking is a pleasant habit with health benefits and only a 50/50 chance of withdrawal symptoms – and that’s only if you stop abruptly rather than tapering. Dr. Frantz’s article was very misleading.