A groundbreaking study published in the journal PLOS One on August 27, 2025, reveals that the widely recognized “unhappiness hump”—a peak in stress, worry, and depression during midlife—may no longer exist. This shift is attributed to a noticeable decline in mental health among younger populations. The research, led by David Blanchflower of Dartmouth College, suggests significant changes in the patterns of mental well-being across age groups.
Traditionally, a U-shaped pattern of well-being has been observed globally, where happiness declines from childhood, hits a low around age 50, and then improves in later years. This trend has been documented in both developed and developing countries since 2008. However, recent data indicate that this pattern is changing, particularly due to declining mental health among younger individuals.
New Insights from Comprehensive Data Analysis
Blanchflower and his team conducted an extensive analysis using data from U.S. and U.K. surveys. The U.S. data included responses from over 10 million adults, collected by the Centers for Disease Control and Prevention between 1993 and 2024. The U.K. data were part of the ongoing U.K. Household Longitudinal Study, involving 40,000 households from 2009 to 2023.
The findings reveal that the “ill-being” hump has vanished in both the U.S. and the U.K. Instead of peaking in midlife, unhappiness now tends to decline steadily over a lifetime. Interestingly, mental health among individuals in their late 40s and older remained relatively unchanged, pointing to a more profound shift among younger people.
Global Perspective: A Worldwide Trend
Expanding their research, the team analyzed data from the Global Minds study, which included nearly 2 million participants from 44 countries between 2020 and 2025. This broader analysis confirmed the disappearance of the unhappiness hump on a global scale.
“Ours is the first paper to show that the decline in young people’s mental health in recent years means that today, both in the United States and the United Kingdom, mental ill-being is highest among the young and declines with age. This is a huge change from the past when mental ill-being peaked in middle age,” the authors noted.
Exploring the Causes: Economic and Social Factors
The reasons behind this shift remain speculative. The researchers propose several potential factors, including the long-term effects of the Great Recession on job prospects for young people, insufficient mental health care resources, the psychological impact of the COVID-19 pandemic, and the pervasive influence of social media.
These elements may have collectively contributed to a mental health crisis among younger demographics, warranting further investigation to understand their precise roles and interactions.
Expert Opinions and Future Implications
Experts emphasize the need for urgent attention to the mental health challenges faced by young people today. Addressing these issues could involve enhancing mental health services, implementing policies to improve economic stability for young adults, and promoting healthier social media usage.
The disappearance of the unhappiness hump suggests a paradigm shift in how mental health evolves with age, with potential implications for public health strategies and resource allocation in the coming years.
Next Steps and Research Directions
Further research is essential to explore the underlying causes of this phenomenon and to develop targeted interventions. Understanding the interplay between economic conditions, social factors, and mental health is crucial for crafting effective solutions.
As the study concludes, “Our concern is that today there is a serious mental health crisis among the young that needs addressing.” The authors call for continued exploration and action to mitigate this growing issue.
For more detailed information, the full study is available in PLOS One and can be accessed here.
Citation: Blanchflower DG, Bryson A, Xu X (2025) The declining mental health of the young and the global disappearance of the unhappiness hump shape in age. PLoS One 20(8): e0327858. https://doi.org/10.1371/journal.pone.0327858
