Decades of scientific inquiry have found that the quality and length of a person’s life goes up when they experience less depression, anxiety, or other Mental health conditions. More recent studies of psychological well-being—also referred to as happiness, flourishing, thriving, or the good life (among other terms)—have been reporting positive links to health and longevity.

For many, this combination of findings raises a question: “Does human mortality depend on the presence of human happiness and flourishing, or merely on the absence of Mental health symptoms or bad feelings?”

That’s what Max Genecov and David S. Yeager explored in a recent meta-analysis, which combined findings from 99 different studies that measured Mental health symptoms and conditions, well-being scores, and lifespan. Importantly, all the studies that they drew from used a longitudinal method, which means they took measurements repeatedly over time to explore whether momentary scores or score changes over time (e.g., well-being in early adulthood, or improvement in well-being) correspond with later scores or changes in another factor (such as the age or cause of death).

Well-being is generally understood as a combination of regularly feeling positive emotions, being satisfied with your life, and having a sense of meaning and purpose in life; ill-being reflects frequent and persistent negative emotions, chronic dissatisfaction, and purposelessness.

To get at this question of whether mental ill-being and well-being over time had overlapping, combined, or independent effects on all-cause mortality, Genecov and Yeager used a statistical approach that allowed them to correct for multiple factors under consideration. Their method was able to mathematically enumerate the impact of well-being on mortality while subtracting any coexisting impact of Mental health challenges on mortality.

Why? Because if well-being and ill-being exist on a continuum, where reducing Mental health conditions is ultimately the same as increasing well-being, then subtracting out the effects of ill-being would erase any concurrent benefit of higher well-being to mortality. But, if improving well-being and reducing ill-being independently affect mortality, where deteriorating Mental health conditions and rising well-being contribute separately to how long a person lives, then their model would show distinct advantages of higher well-being to longevity above and beyond reducing symptoms of ill-being.

The result? In this study, people with higher-than-average well-being did live longer—and, indeed, this effect occurs above and beyond the lifespan advantages of lower-than-average ill-being. As the researchers sum up their results:

People one standard deviation above the average on well-being die at a 14% slower rate than those with average well-being. . . . As a practical reference using death probabilities from a 2020 United States Social Security Administration actuarial life table, a standard deviation increase on well-being corresponds to just under two years of more life for both men and women.

They saw older adults and patient populations with greater well-being live longer, and they also found people living longer who rated high in optimism, life satisfaction, positive emotion, a sense of social support, and purpose in life. This result isn’t new in the research, but by looking at the effects of ill-being, they were able to clarify its relationship to well-being and longevity. In fact, Genecov and Yeager found that the lifespan boost documented in their study (which controlled for the possible benefits of alleviating ill-being) was comparable to other studies of well-being and longevity that didn’t control for ill-being. This suggests that prior studies have also been capturing the unique and separate benefit of well-being to health and longevity.

While easy to grasp why, for example, less chronic stress would lead to better cardiovascular health and so a longer life, it’s not as clear from a scientific perspective why or how better overall well-being could help someone live longer. Right now, we know that optimism, positive emotion, social support, and purpose are associated with a longer life—we’re just not sure why, exactly.

That said, there are many ways mental well-being could fuel a longer and better life. More optimistic people, for example, tend to make healthier choices around physical exercise and diet, and to not smoke cigarettes. Positive emotions are linked to investing more effort toward and pursuing goals in life. People who score higher on measures of well-being are more socially appealing, generous, and compassionate toward others, and enjoy higher-quality friendships. One of the most famous studies of longevity attributes survival most strongly to supportive social bonds.

While still an emerging science, those findings suggest that well-being and related factors evoke experiences and motivate behaviors that measurably strengthen physical health in life-lengthening ways. While eliminating ill-being may diminish risks, obstacles, and barriers to physical health, fostering well-being may optimize physical systems to enhance stability, efficiency, and strength—both ultimately contributing to longevity but in different, often intersecting, ways.

Want to do more to enhance your well-being? The Greater Good Science Center has an entire website dedicated to supporting people who’d like to increase well-being called Greater Good in Action. You can explore and tinker with over 150 well-being–promoting activities, exercises, and practices drawn from published research, join a four-week Pathway to Happiness program, or try the seven-day Big JOY project.