New research indicates that caffeine consumption is associated with subsequent increases in positive affect, and this association is strongest within the first 2.5 hours after awakening (i.e., in the morning).
People who regularly consume caffeine are usually in a better mood after a cup of coffee or another caffeinated drink, an effect that is much more pronounced in the morning than later in the day. Image credit: Sci.News.
“Caffeine is a central nervous system stimulant that is used by approximately 80% of the world’s population and consumed in a wide variety of forms, including beverages like coffee, tea, soda (e.g., coke), and energy drinks, but also in food items such as chocolate,” said Bielefeld University researcher Justin Hachenberger and his colleagues.
“Positive expectations related to caffeine consumption include reduced tiredness and fatigue, enhanced cognitive and physical performance, and a positive shift in mood.”
“While there is a large body of evidence for such beneficial effects coming from experimental studies, there is a lack of studies investigating associations of caffeine particularly with mood or affective states in naturalistic, real-world settings.”
The study involved 236 young adults from Germany over a period of up to four weeks.
The participants completed short questionnaires on their smartphones seven times a day, indicating their current mood and whether they had consumed a caffeinated drink in the preceding 90 minutes.
Accordingly, the study focused on caffeine consumption in everyday life, not just in artificial laboratory settings.
The researchers also investigated whether coffee has different effects on different individuals.
“We were somewhat surprised to find no differences between individuals with varying levels of caffeine consumption or differing degrees of depressive symptoms, anxiety, or sleep problems,” Dr. Hachenberger said.
“The links between caffeine intake and positive or negative emotions were fairly consistent across all groups.”
“We expected that people with higher levels of anxiety would experience negative mood changes, such as increased nervousness, after consuming caffeine.”
“However, people who react to caffeine in a bad way may avoid it and that the study did not include people who completely abstain from caffeine.”
The scientists explain the mood-boosting effect of caffeine on morning mood with its ability to block adenosine receptors, which promotes wakefulness and makes people feel more energetic.
“Caffeine works by blocking adenosine receptors, which can increase dopamine activity in key brain regions — an effect that studies have linked to improved mood and greater alertness,” said University of Warwick’s Professor Anu Realo.
“Yet, it remains unclear whether these effects are related to a reduction in withdrawal symptoms after a night’s sleep.”
“Even people with moderate caffeine consumption can experience mild withdrawal symptoms that disappear with the first cup of coffee or tea in the morning.”
The study appears in the journal Scientific Reports.
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J. Hachenberger et al. 2025. The association of caffeine consumption with positive affect but not with negative affect changes across the day. Sci Rep 15, 28536; doi: 10.1038/s41598-025-14317-0