An observational study published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging has investigated the relationship between caffeine consumption, sleep, and brain structure in adolescents. The research, which included data from nearly 10,000 children aged 9-11, suggests an association between caffeine intake and certain aspects of brain structure and sleep.
Professor Derek Hill of UCL noted that the study proposes sleep and brain structure may mediate the link between caffeine intake and mental health outcomes. However, he cautioned that the findings should be considered speculative due to significant limitations in the study design, including brain imaging at a single timepoint and parent-reported sleep measures.
Dr Charalampos Rallis from Queen Mary University of London described the study as large and well-conducted, but emphasised that its observational design cannot establish that caffeine causes changes in children's brains. He added that the observed brain differences were very small and the association with later mental health was negligible. Dr Rallis concluded that the most robust finding, consistent with existing evidence, is that caffeine can reduce sleep in children.