Your Morning Coffee May Be a Placebo, Neuropsychologists Find

While many people staunchly believe that they can't start the morning without a good old cup of joe, scientists have found that our brains might be lying to us about how much we need that coffee.

The feeling of alertness experienced by people starting the day with a cup of coffee might actually be more of a placebo effect related to the experience of drinking the coffee, rather than only due to the effects of the caffeine itself, according to a paper published in the journal Frontiers in Behavioral Neuroscience on June 28.

"There is a common expectation that coffee increases alertness and psychomotor functioning," Nuno Sousa, co-author of the study and professor of neuropsychiatry at the University of Minho, said in a statement. "When you get to understand better the mechanisms underlying a biological phenomenon, you open pathways for exploring the factors that may modulate it and even the potential benefits of that mechanism."

In the paper, the authors describe how they performed MRI scans on people who usually drank at least one coffee per day. They initially took the MRI scans after the participants had refrained from eating or drinking caffeinated beverages for at least three hours, and then again after they had drank coffee, or instead, taken caffeine.

The average 8-oz cup of coffee contains 80 to 100 milligrams of caffeine, according to the FDA. Caffeine acts as a central nervous system stimulant, binding to adenosine receptors that usually trigger drowsiness, encouraging alertness, and allowing dopamine and other stimulating neurotransmitters to act, increasing brain activity. As a result, consuming caffeine can aid in increased energy and the ability to concentrate, Harvard School of Public Health reported.

Therefore, the authors expected that the MRI scans after drinking both the caffeinated coffee and taking the caffeine would result in higher integration of brain networks that are linked to the prefrontal cortex (associated with executive memory), and the default mode network (involved in introspection and self-reflection processes).

The results of the MRI revealed that the connectivity of the default mode network was indeed decreased after drinking coffee and after taking caffeine, showing that consuming both caffeine and coffee made it easier for people to wake up and feel alert.

"Acute coffee consumption decreased the functional connectivity between brain regions of the default mode network, a network that is associated with self-referential processes when participants are at rest," Maria Picó-Pérez, first author of the paper and neuropsychology researcher at Jaume I University, said in the statement. "In simple words, the subjects were more ready for action and alert to external stimuli after having coffee."

They also found, however, that those who drank coffee also had increased connectivity in the higher visual network and the right executive control network, something that didn't happen in those who only took caffeine. This indicates that these parts of the brain, involved in working memory, cognitive control, and goal-directed behavior, require the experience of drinking coffee, not just the caffeine.

"Taking into account that some of the effects that we found were reproduced by caffeine, we could expect other caffeinated drinks to share some of the effects," Picó-Pérez said. "However, others were specific for coffee drinking, driven by factors such as the particular smell and taste of the drink, or the psychological expectation associated with consuming that drink."

The authors recognized the limitations of their research, noting they did not test if non-caffeinated coffee could provide the same results as caffeinated coffee. They also cautioned that the benefits experienced by the coffee drinkers may actually be due to the relief of withdrawal symptoms, which were not tested for in this study.

"The changes in connectivity were studied during a resting-state sequence. Any association with psychological and cognitive processes is interpreted based on the common function ascribed to the regions and networks found, but it was not directly tested," Sousa said. "Moreover, there could be individual differences in the metabolism of caffeine among participants that would be interesting to explore in the future."

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