Morning coffee's effects may be placebo, study suggests

Coffee is often thought to make you feel more alert, so people drink it to wake themselves up and improve their efficiency. Portuguese scientists studied coffee drinkers to understand whether the wakefulness effect is dependent on the properties of caffeine, or whether it’s about the experience of drinking coffee.

The scientists recruited people who drank at least one cup of coffee daily and asked them to refrain from eating or drinking caffeinated beverages for at least three hours before the study. They interviewed the participants to collect sociodemographic data and then did two brief functional MRI scans: one before and one 30 minutes after either taking caffeine or drinking a standardized cup of coffee. During the functional MRI scans, the participants were asked to relax and let their minds wander.

They found that the connectivity of the default mode network was decreased both after drinking coffee and after taking caffeine, which indicates that consuming either caffeine or coffee made people more prepared to move from resting to working on tasks.

However, drinking coffee also increased the connectivity in the higher visual network and the right executive control network - parts of the brain that are involved in working memory, cognitive control, and goal-directed behavior. This didn’t happen when participants only took caffeine. In other words, if you want to feel not just alert but ready to go, caffeine alone won’t do – you need to experience that cup of coffee.

Reference: Coffee consumption decreases the connectivity of the posterior DMN at rest, Frontiers in Behavioral Neuroscience, DOI 10.3389/fnbeh.2023.1176382