"I'm a zombie without my morning coffee." "My blood type is Diet Coke." "Caffeine isn't a drug, it's a vitamin." Most people make jokes like these about needing a daily boost from their favorite caffeinated beverage—whether first thing in the morning or to prevent the after-lunch slump.
But a recent study coauthored by American University psychology professor Laura Juliano indicates that more people are dependent on caffeine to the point that they suffer withdrawal symptoms and are unable to reduce caffeine consumption even if they have another condition that may be impacted by caffeine—such as a pregnancy, a heart condition, or a bleeding disorder.
These symptoms combined are a condition called "Caffeine Use Disorder." And according to the study Juliano coauthored, even though caffeine is the most commonly used drug in the world—and is found in everything from coffee, tea, and soda, to OTC pain relievers, chocolate, and now a whole host of food and beverage products branded with some form of the word "energy"—health professionals have been slow to characterize problematic caffeine use and acknowledge that some cases may call for treatment.
"The negative effects of caffeine are often not recognized as such because it is a socially acceptable and widely consumed drug that is well integrated into our customs and routines," Juliano said. "And while many people can consume caffeine without harm, for some it produces negative effects, physical dependence, interferes with daily functioning, and can be difficult to give up, which are signs of problematic use."
"Caffeine Use Disorder: A Comprehensive Review and Research Agenda," which Juliano coauthored with Steven Meredith and Roland Griffiths of the Johns Hopkins University School of Medicine and John Hughes from the University of Vermont, published last fall in the Journal of Caffeine Research.
Grounds for More Research
The study summarizes the results of previously published caffeine research to present the biological evidence for caffeine dependence, data that shows how widespread dependence is, and the significant physical and psychological symptoms experienced by habitual caffeine users. Juliano and her coauthors also address the diagnostic criteria for Caffeine Use Disorder and outline an agenda to help direct future caffeine dependence research.
In so far as heeding the call for more research, the scientific community is beginning to wake up and smell the coffee. Last spring, the American Psychiatric Association officially recognized Caffeine Use Disorder as a health concern in need of additional research in the Diagnostic and Statistical Manual of Mental Health Disorders—the standard classification of mental disorders, now in its fifth edition (DSM-5), used by mental health professionals in the United States.
"There is misconception among professionals and lay people alike that caffeine is not difficult to give up. However, in population-based studies, more than 50 percent of regular caffeine consumers report that they have had difficulty quitting or reducing caffeine use," said Juliano, who served as an appointed advisor to the DSM-5 Substance Use Disorders work group and helped outline the symptoms for the Caffeine Use Disorder inclusion.
"Furthermore, genetics research may help us to better understand the effects of caffeine on health and pregnancy as well as individual differences in caffeine consumption and sensitivity," she added.
A Lack of Labelling
Based on current research, Juliano advises that healthy adults should limit caffeine consumption to no more than 400 mg per day—the equivalent of about two to three 8-oz cups of coffee. Pregnant women should consume less than 200 mg per day and people who regularly experience anxiety or insomnia—as well as those with high blood pressure, heart problems, or urinary incontinence—should also limit caffeine.
But limiting one's caffeine intake is often easier said than done as most people don't know how much caffeine they consume daily.
"At this time, manufacturers are not required to label caffeine amounts and some products such as energy drinks do not have regulated limits on caffeine," Juliano said, adding that if this changed, people could perhaps better limit their consumption and ideally, avoid caffeine's possible negative effects.
But in a nation where a stop at Starbucks is a daily ritual for many people, is there really a market for caffeine cessation? Juliano says yes.
"Through our research, we have observed that people who have been unable to quit or cut back on caffeine on their own would be interested in receiving formal treatment—similar to the outside assistance people can turn to if they want to quit smoking or tobacco use."