[Subjective happiness among Japanese adults: An upward tendency associated with age]

Objectives　The present study investigated subjective happiness in Japanese adults and offers basic knowledge for future studies. In addition, how subjective happiness varies in relation to certain demographic variables, such as gender and age, as well as factors that influence this variability, are examined.Methods　A total of 2,000 Japanese people (1,000 females and 1,000 males) over the age of 20 completed an anonymous self-report internet survey. There were approximately the same number of participants in each of six age groups ranging from the 20s to 70s. How Subjective Happiness Scale (SHS) scores were related to various demographic variables, including gender and age, as well as happiness, life satisfaction, and stress response, were analyzed.Results　The validity of the SHS was supported by positive correlations with happiness and life satisfaction scores and negative correlation with stress response scores. The results also showed that females had higher SHS scores than males, and this gender difference was distinctive, especially among young adults. In addition, there was a U-shaped change in SHS score by age. That is, subjective happiness dropped with age, but started increasing again after the 50s. The same findings were reconfirmed by an additional survey one year later. Moreover, those with a spouse showed higher SHS scores than unmarried participants. Lastly, SHS scores were low among those whose highest education was junior high school and those who lived alone, although the limitations of sampling bias should be considered.Conclusion　The SHS is an internationally accepted measure of subjective happiness consisting of only four items and can easily be used in public health research and practice. The current study offers basic information regarding SHS scores as well as subjective happiness in Japanese adults of different age groups and genders. The findings of the present study clearly indicate higher levels of subjective happiness among older age groups than younger ones, those with a spouse than those without a spouse, and females than males. As many studies conducted in other cultures have shown no such gender difference, further cross-cultural comparison studies are needed to clarify this discrepancy. The SHS as an indicator of personal well-being can be strongly expected to show extended utility in the future.