The Famous “Unhappiness Hump” Has Vanished, and Youth Are Paying the Price

Once a universal feature of human psychology, the “unhappiness hump” in midlife has disappeared, replaced by a new trend: mental health is worst in youth and improves with age.

Data from the U.S., U.K., and dozens of countries suggest today’s young people are driving this shift, facing deeper struggles than previous generations.

New Study Challenges the Midlife Unhappiness Hump

A large new survey study suggests that the long-recognized “unhappiness hump” (the rise in stress, worry, and depression that typically increases with age, reaches its highest point in midlife, and then eases in older adulthood) may no longer exist. Researchers, led by David Blanchflower of Dartmouth College, U.S., reported the results in the journal PLOS One.

Since 2008, scientists have consistently documented a U-shaped relationship between age and well-being, where happiness tends to decrease from youth into midlife and then improve later in life. Alongside this pattern, data have shown an “ill-being” curve, often described as the unhappiness hump.

Evidence From U.S. and U.K. Surveys

Recent studies suggest that well-being among younger generations is falling worldwide, yet few investigations have considered what this means for the traditional unhappiness hump. To explore this, Blanchflower and his team examined survey results from both the United States and the United Kingdom that included questions on mental health. The U.S. dataset drew from more than 10 million adults surveyed by the Centers for Disease Control and Prevention (CDC) between 1993 and 2024. In the U.K., data were taken from the ongoing Household Longitudinal Study, which has followed 40,000 households from 2009 through 2023.

Their analysis revealed that in both the U.S. and U.K., the midlife peak in unhappiness has disappeared. Instead, levels of ill-being now tend to decline steadily with age. Among people in their late 40s and older, mental health patterns have remained relatively stable. The shift seems to stem from worsening mental health in younger age groups, rather than improvements among older adults.

Global Data Confirm a Worldwide Shift

Next, the researchers analyzed data on nearly 2 million people from 44 countries, including the U.S. and the U.K., from a mental health study called Global Minds. Covering the years 2020 through 2025, these data suggest the unhappiness hump has disappeared worldwide.

Reasons for the disappearance of the unhappiness hump are unclear. The authors suggest several possibilities, including long-term impacts of the Great Recession on job prospects for younger people, underfunded mental health care services, mental health challenges posed by the COVID-19 pandemic, and increased social media use. Further research is needed to determine whether any of these or other factors are at play.

A Historic Reversal in Mental Health Trends

The authors add: “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 reasons for the change are disputed, but our concern is that today there is a serious mental health crisis among the young that needs addressing.”

Reference: “The declining mental health of the young and the global disappearance of the unhappiness hump shape in age” by David G. Blanchflower, Alex Bryson and Xiaowei Xu, 27 August 2025, PLOS ONE.
DOI: 10.1371/journal.pone.0327858

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