For many years, researchers believed that happiness follows a U-shaped path in life. People tend to feel fine as children, then become more stressed or unhappy during their 30s and 40s.
This dip in happiness, often called the “unhappiness hump,” usually peaks around age 50. After that, people tend to feel better again as they get older. This pattern has been seen in many countries around the world, whether they are rich or poor.
But a new study from Dartmouth College in the United States suggests that this pattern has changed. The study, led by David Blanchflower, was published in the journal PLOS ONE. It found that the traditional midlife dip in happiness has disappeared. In fact, it seems that younger people are now the most likely to report feeling depressed, anxious, and unhappy.
To understand this shift, the researchers looked at a huge amount of data. They studied surveys from over 10 million adults in the United States, collected from 1993 to 2024 by the Centers for Disease Control and Prevention. They also used data from the UK Household Longitudinal Study, which followed 40,000 households in the United Kingdom from 2009 to 2023.
Their results were surprising. The old pattern of middle-aged people being the least happy no longer appeared. Instead, younger people are now showing the highest levels of mental health problems.
The older age groups have stayed about the same, but younger people’s mental health has gotten worse. This change has flattened the U-shaped curve and, in some cases, turned it upside down.
To see if this trend was happening elsewhere, the team looked at more data from nearly 2 million people in 44 countries. These responses were collected between 2020 and 2025 through a project called Global Minds. Again, the same trend was found: younger people were more likely to report poor mental health than older adults.
The researchers don’t have just one reason for this change, but they suggest several possible causes. One factor may be the Great Recession, which hurt job prospects and financial security for many young people.
Another issue is the lack of access to good mental health services. Many young people find it hard to get the help they need. The COVID-19 pandemic also played a big role, bringing more stress, loneliness, and uncertainty. Social media use, which has become a big part of life, may also be making things worse for young people’s mental health.
This study is one of the first to clearly show such a major change in how mental health varies with age. The researchers say their most important finding is that young people today are struggling more than ever. In the past, people expected to feel more stressed during midlife, but now, those feelings are showing up much earlier.
The team hopes their research will bring more attention to this issue. They call for better support systems, more mental health services, and further research to understand what is happening and how to help.
In summary, this study shows that the old pattern of happiness through life may no longer fit. Mental health struggles are now hitting young people the hardest, and this needs action from health experts, schools, and government leaders.
If you care about mental health, please read studies about how dairy foods may influence depression risk, and 6 foods you can eat to improve mental health.
For more mental health information, please see recent studies about top foods to tame your stress, and Omega-3 fats may help reduce depression.
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