Young people who consume higher amounts of caffeine, primarily through soft drinks, experience reduced sleep durations and exhibit subtle structural differences in brain development, according to a study published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging (DOI: 10.1016/j.bpsc.2026.09.011). Researchers at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London analyzed data from thousands of participants to map how everyday dietary habits intersect with neurological growth during early adolescence.
Data from 9,632 Children Reveals Structural Patterns Across 22 Brain Regions
The investigation drew on data from 9,632 children aged nine to eleven participating in the Adolescent Brain Cognitive Development (ABCD) Study, a long-term research project tracking health and brain development across the United States. Participants reported their weekly intake of caffeinated beverages, including coffee, tea, and soft drinks, while parents provided average sleep duration figures. Magnetic resonance imaging (MRI) scans subsequently measured the thickness and surface area of the cerebral cortex, the folded outer layer responsible for decision-making, cognitive processing, attention, and emotional regulation.
Follow-up mental health assessments conducted 6 and 18 months later revealed that increased caffeine consumption correlated with a reduced surface area across the cortex. This pattern manifested across 22 distinct regions covering all four lobes of the brain, persisting even after researchers adjusted for household socioeconomic factors such as parental income and educational attainment. Measurable differences in overall surface area appeared among children consuming as little as one caffeinated drink per week compared to those consuming none, with soft drinks serving as the primary source of caffeine in the cohort.
Caffeine is such a normal part of daily life that it’s easy to forget young people are consuming it too. Studies have found that two-thirds of adolescents consume caffeine at least once a week. Despite it being a psychoactive substance, it is completely unregulated.Dr Divyangana Rakesh
Sleep Shortening Serves as a Key Underlying Link to Mental Health Outcomes
Investigating the underlying mechanics connecting dietary caffeine to cortical structure, the research team found that higher consumption directly correlated with shorter sleep durations. This sleep deficit partially accounted for the observed reduction in cortical surface area. Together, diminished sleep and altered brain structure helped explain the pathway between higher caffeine intake and subsequent mental health challenges reported six months later, specifically involving attention, mood, and behavioral difficulties. By the 18-month mark, however, only the structural link through overall cortical surface area remained statistically significant.
We found that even fairly low levels of intake were linked to small differences in brain structure and later mental health, and lower sleep duration seems to be an important underlying link. Although we cannot comment on causality, our results do suggest that both caffeine intake, including from soft drinks, and sleep are worth paying attention to when we think about young people’s mental health,Dr Divyangana Rakesh, Senior Lecturer in Neuroscience and Psychology
Researchers emphasize that untangling the precise biochemical role of caffeine remains complex due to concurrent lifestyle factors associated with sugary beverages. Soft drinks frequently accompany higher rates of risk-taking behaviors and less nutritious dietary habits, obscuring the isolated impact of the stimulant itself. Future investigations aim to utilize more precise measurements regarding the exact timing, quantity, and beverage types consumed by adolescents, alongside more rigorous tracking of sleep patterns.
Soft drinks contain a lot of sugar and often go hand in hand with less healthy lifestyle habits and more risk-taking behaviours, so we can’t yet separate the role of caffeine from everything else that comes with them. That’s the next question we want to answer, ideally with more precise measures of what young people drink, when they drink it and how well they sleep.Jiayi Zheng, first author of the study from the IoPPN at King’s College London
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