Overview

• University of Bristol researchers linked X posting times to data from the Children of the 90s cohort, analysing 18,288 posts from 310 people between 2008 and 2023.
• Average activity between 11 pm and 5 am was associated with meaningfully lower mental wellbeing than daytime posting.
• Overnight posting explained nearly 2% of the variation in overall wellbeing, with weaker associations for depression and anxiety.
• The findings, published in Scientific Reports, are observational and do not establish causation.
• Authors highlight displaced sleep, cognitive arousal and blue-light effects as plausible mechanisms and say the results could inform targeted interventions or legislation.