Addicted to Speculation About Caffeine

Here's a news item you won't likely see:

Withdrawal doesn't equal addiction

A handful of scientists have proven that withdrawal from caffeine is a real, significant, and severe phenomenon among those who drink large quantities of caffeinated beverages daily.1 No one disagrees that withdrawal from, and even tolerance to, caffeine can occur. But withdrawal and tolerance are not “addiction,” as I have pointed out in past commentaries.

The confusion concerns whether caffeine overuse can lead to three of the seven DSM diagnostic characteristics that would cause an overuser to be labeled “dependent,” and the evidence for this is arguable. However, in most media reports of scientific studies on caffeine withdrawal, erroneous headlines read something along the lines of “More evidence that caffeine is addicting.”

The National Institute on Drug Abuse (NIDA), which synthesizes scientific information on drugs of abuse for professionals and the public, does not label caffeine as addicting or dependence producing. NIDA includes a scant amount of scientific information on caffeine on its Web site. This should strongly indicate that caffeine is not considered a dangerous “drug.”

To suggest that caffeine “addiction” somehow belongs in the same category as cocaine addiction, heroin addiction, alcohol addiction, and nicotine addiction gives the term “addiction” a bad name. We have enough stigma in this field without labeling all overuse of any chemical or any “I really like it” activity as an addiction. This is not to say that spending too much time on one thing is healthy, but such activities/obsessions fall far short of equaling the devastation produced by dependence on alcohol, nicotine, heroin, or cocaine.

Effects on the brain

What is clear is that caffeine produces a small effect on dopamine release in the brain's reward pathway, just like other pleasure-producing substances. What is not clear is whether caffeine can produce dependence by affecting the reward pathway-associated areas that become “neuroadapted” during long-term exposure to a drug.

Scientists know that simply producing pleasure through the release of dopamine in the mesolimbic system is unrelated to the development of dependence (for example, nicotine produces much less pleasure than cocaine, yet both are highly dependence producing). Available research suggests that caffeine “does not have what it takes” in terms of specificity and potency to neuroadapt the critical systems in the mesolimbic areas of the brain. More research would be necessary to determine definitively whether caffeine can do this.

But don't we have better things to do than spend money on determining whether caffeine is addicting? It is important to promote more research on drugs. But unless research on caffeine can provide us with new information on mechanisms of dependence production and its possible reversal (for treatment purposes), the discussion of whether caffeine is addicting is simply an academic pursuit.

Reference

1. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: Empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharm 2004; 176:1-29.