A recent study published in PLOS One failed to find evidence that caffeine consumption is linked to changes in a brain connectivity marker associated with attention in early adolescents. Researchers examined whether drinking caffeinated beverages affects the relationship between two key brain networks involved in attention and internal thought. While previous research in adults has suggested caffeine can alter brain connectivity, this large-scale investigation did not find any such effects in youth.
Caffeine is widely consumed across all age groups, including children and adolescents. Beverages like soda, tea, coffee, and energy drinks are common sources of caffeine among youth in the United States. Surveys suggest that a majority of adolescents ingest caffeine on a typical day. This has raised questions about how the stimulant may impact developing brains, especially since past research indicates that caffeine use in children may be linked to lower scores in memory and attention-related tasks.
Previous studies have shown that caffeine affects brain activity in adults, especially within the brain’s large-scale functional networks. These networks, including the default mode network and the dorsal attention network, operate in opposition to each other. The default mode network tends to be active when people are engaged in self-reflective or inward-focused thinking, while the dorsal attention network is more active during tasks that require external focus and attention. In healthy brains, these two systems show a negative correlation or “anticorrelation,” which means that when one is more active, the other tends to be less active. This dynamic balance is thought to be important for attention and task performance.
In adults, stronger anticorrelation between these networks is often linked with better attention and mental focus. Studies have also found that caffeine can change patterns of brain connectivity in adults, although it is not yet clear whether these same effects occur in younger individuals. This prompted the researchers to explore whether recent caffeine intake in early adolescents might alter the anticorrelation between these two brain networks.
“I am fascinated by society’s most popular drug, caffeine. Caffeine can have a negative impact on cognitive functioning in youth, and many youths consume caffeinated beverages. The default mode network and dorsal attention network are two anticorrelated brain networks that are linked to attention. We wanted to explore whether caffeine consumption among youths was associated with the anticorrelation of these two large anticorrelated brain networks that are linked to attention,” said study author Orrin Ware, an assistant professor at the University of North Carolina at Chapel Hill School of Social Work.
To answer this question, the researchers analyzed baseline data from the Adolescent Brain Cognitive Development Study, the largest long-term study of brain development in the United States. This dataset includes detailed information about brain imaging, behavior, and lifestyle factors from thousands of children. For the current study, the researchers focused on a sample of 4,673 youth, aged around 9 to 10 years, who had completed brain scans and provided self-reported data on their caffeine consumption.
Participants were asked whether they had consumed any caffeinated beverages in the past 24 hours and how many caffeinated drinks they typically consumed per week. The researchers then calculated the strength of anticorrelation between the default mode network and the dorsal attention network using resting-state functional magnetic resonance imaging. This technique measures spontaneous brain activity while the participant is not performing any specific task.
The researchers used statistical models that accounted for potential confounding factors such as age, sex, attention problems, body mass index, head movement during the scan, and the specific MRI scanner used. They tested whether recent or regular caffeine use was associated with changes in the anticorrelation between the two networks.
Contrary to their expectations, the researchers found no significant associations. About 16 percent of participants reported having a caffeinated drink in the past 24 hours, and around 71 percent reported drinking such beverages weekly. However, neither the short-term nor the weekly caffeine intake predicted differences in brain network connectivity. The anticorrelation between the default mode network and the dorsal attention network remained unaffected by caffeine use, even after adjusting for other variables.
The researchers also tested whether the combined effect of both recent and weekly caffeine consumption might influence the network relationship, but this interaction was also not statistically significant. The findings were consistent across multiple types of statistical analysis, including a comparison of models with and without caffeine-related variables.
“After controlling for other factors such as age and sex, we did not find an association between caffeinated beverage consumption and the anticorrelation between the default mode network and the dorsal attention network,” Ware told PsyPost.
Although caffeine intake was not linked to changes in the main outcome of interest, some covariates were associated with differences in the anticorrelation strength. For example, older children and girls showed slightly stronger anticorrelations. Children with more attention problems or those who were underweight tended to have weaker anticorrelations. Greater head motion during the scan and differences in the MRI scanner also contributed to variations in the results.
The lack of a significant relationship between caffeine intake and network connectivity may have several explanations. One possibility is that the amount of caffeine consumed by these children was too low to produce detectable effects on brain function. It is also unclear whether participants drank caffeinated beverages before or after the scan, which could influence the results.
“An important limitation is that the caffeinated beverage consumption data were self-reported,” Ware noted. “Another limitation is the variability in the amount of caffeine in milligrams among different brands of caffeinated beverages.”
The findings have implications for interpreting brain imaging studies in young people. Since some children may consume caffeine before undergoing a scan, there was a concern that this might distort measures of brain function. The current study suggests that, at least in early adolescence, typical levels of caffeine consumption are unlikely to significantly affect this key network measure.
However, the study also raises questions about other possible effects of caffeine on brain connectivity and behavior that were not captured here. For example, the researchers only examined the relationship between two networks. Future studies might explore whether caffeine impacts other brain systems involved in reward, emotion, or executive function.
The study, “Examining recent effects of caffeine on default mode network and dorsal attention network anticorrelation in youth,” was authored by Orrin D. Ware, Sarah E. Chang, Wesley K. Thompson, Alexandra S. Potter, Hugh Garavan, Micah E. Johnson, and Lucina Q. Uddin.
