Trends in Distress-Free Life Expectancy in Japan, 2010–2022

Extensive literature exists on the physical health of the Japanese population whereas relatively little is known about their mental health. Moreover, most studies have assessed physical and mental health separately, and this further confounds the relationship between the two. Using the concept of health expectancy, this study investigated the trends in the relationship between physical and mental health among Japanese men and women aged 20 years or more between 2010 and 2022. Psychological distress, based on the Comprehensive Survey of Living Conditions, was used as an indicator of mental health. We employed Sullivan's method to estimate the length of life with or without distress of varying degrees. Our results showed substantial improvements in distress-free life expectancy for both genders during the study period. Younger people have gained more distress-free years than their older counterparts, placing older individuals, especially men, at an increased risk of psychological distress. These findings contribute to the literature on longevity in Japan by quantifying the role of mental health in the population's overall health. Given the recent increase in mental health problems, greater policy emphasis on the relationship between physical and mental health status is required.