Official URL: https://doi.org/10.1002/jad.12037

Introduction: While several studies have documented a declining‐with‐age trend inlife satisfaction in adolescence, cross‐national and nationally representative long-itudinal evidence is needed to establish the normative trajectory of life satisfactionduring this critical developmental period.Methods: The Health Behaviour in School‐Aged Children (HBSC) study of 10–16‐year‐olds included the Cantril Ladder life satisfaction measure in surveys of 43countries between 2001 and 2014 (N = 752,620, 51% females). The UK HouseholdLongitudinal Study (UKHLS) was used to assess within‐person changes in life sa-tisfaction from age 10 to 15 years among young people sampled between 2009 and2018 (N = 8952, Obs. = 30,278).Results: Life satisfaction decreased by 0.61 SDs on average from ages 10 to 16 in theHBSC sample. A statistically significant decreasing‐with‐age trend was observed ineach of the 43 countries examined. Females experienced a more pronounced declinein life satisfaction than males (0.75 SD vs. 0.46) on average, and a significantly largerdecrease in life satisfaction among females was identified in 38 of 43 countries ex-amined. Longitudinal analysis of adolescents from the UKHLS sample replicated thispattern: life satisfaction declined significantly by 0.5 SD between the ages of 10 and 15and this decline was found to be steeper for females (0.76 SD) than for males(0.23SD).Conclusions: The study findings enhance our understanding of the lifespan dynamicsof life satisfaction and point to a potential universal decline in life satisfaction inadolescence. Understanding the developmental processes underlying this phenom-enon will now be crucial.