Americans have a long reputation for being hopeful. The United States is often characterized by its can-do attitude and the pursuit of the American Dream–the idea that motivated individuals have the freedom to pursue their dreams and improve life for themselves and their families. Indeed, the United States is consistently the most popular destination for people around the world looking to leave their home country.

However, recent surveys suggest that many Americans are losing faith in the future of the nation. A 2023 survey by the Pew Research Center found at least two-thirds of Americans believe that by 2050, America will become economically weaker, less important in the world, and more politically divided. A 2023 Wall Street Journal-NORC survey found that nearly 80% of Americans do not expect life for their children’s generation to be better than it has been for their own generation.

Are we losing hope?

To find out, our team at the Archbridge Institute’s Human Flourishing Lab, in partnership with NORC at the University of Chicago, surveyed a nationally representative sample of just over 2,000 Americans about their hopefulness for the future. We were particularly interested in distinguishing between personal hope and hope at the broader national or global levels. Our results reveal that this distinction is an important one.

The good news is that most Americans continue to have hope in their personal lives: 82% are hopeful for their own future, 85% are hopeful for the future of their family, and 74% are hopeful for the future of their local community. There is some variation across demographic groups, but for the most part, these high levels of hope characterize Americans across diverse gender, age, racial, ethnic, income, and political groups.

Unfortunately, hope drops considerably when we extend it beyond the local environment. Only 56% of Americans are hopeful for the future of the U.S., a particularly distressing trend during an election year. Moreover, only 44% of Americans believe that humans will make significant progress on major societal and global challenges in the coming decades.

We also asked respondents about their current mental health, and that’s where we observed the most striking differences between Americans. As one example, 90% of Americans who say their mental health is good are hopeful for their own future, compared to 49% of Americans who say their mental health is not good.

The real reason for hopelessness

Though we often think about mental health as a personal issue, it has broader societal implications. Mental illness reduces social trust and behaviors that promote societal flourishing such as labor force participation and entrepreneurship. Mental health may also influence people’s visions of the future of the nation and human progress. For instance, in our survey, the percentage of Americans who are hopeful for the future of the country drops from 62% among those who say their mental health is good to 32% among those who say their mental health is poor.

This relationship between mental health and hope also explains the differences we observed across age groups. According to our survey, adults under the age of 30 are generally less hopeful than older Americans. However, this decline appears to be driven by worse mental health among younger cohorts. When we only look at the responses of Americans who say their mental health is good, young adults are just as hopeful as older generations. In fact, mentally healthy young adults are actually the most hopeful group when it comes to the future of the nation–71% are hopeful for the future of the U.S., compared to around 60% in every other age group.

Mental health and related psychological problems such as loneliness may prove to be one of the most significant barriers to human flourishing and progress in our time. Despite living in an age of material abundance, if people don’t adopt a hopeful mindset, they won’t fully utilize their ability to better their lives and address the major challenges we face today. Research demonstrates that, when individuals are hopeful for the future, they are more self-confident, goal-motivated, resilient, engaged in their communities, creative, and innovative. As a result, hopeful people tend to be more successful at achieving their aspirations and are more likely to perceive their lives as meaningful.

We live in a media-saturated world where we are constantly exposed to negative news and grievance-focused social commentary, which can make us feel like the barriers to human progress are insurmountable. But if we look back at historical periods dominated by war, famine, disease, poverty, discrimination, and social upheaval, we would discover that a hopeful mindset–the belief that people have the power to build a better future–played a crucial role in inspiring people to overcome obstacles and create the better world we live in today.

Of course, we haven’t solved all of our old problems, and new ones continue to appear. But that is exactly why hope still matters and always will.

Clay Routledge is vice president of research and director of the Human Flourishing Lab at the Archbridge Institute. Andrew Abeyta is a fellow at the Human Flourishing Lab and an assistant professor of psychology at Rutgers University.

The opinions expressed in Fortune.com commentary pieces are solely the views of their authors and do not necessarily reflect the opinions and beliefs of Fortune.