This study examines the mediating effect of social network size on depression among older adults in Japan in association with the Big Five personality traits: extraversion, agreeableness, conscientiousness, neuroticism, and openness. Cross-sectional data were obtained from 739 older adults (Mean age = 75.13, SD = 6.86) residing in Tokyo. Multiple mediation analyses estimated total, indirect, and direct effects between personality and depression. Extraversion was associated with the number of kin and friend networks and agreeableness with the number of kin networks. Moreover, these social networks partially mediated the effects of extraversion and agreeableness on depression. The findings show that personality traits such as extraversion and agreeableness are associated with social network size, which contributes to better mental health in old age.
Keywords: agreeableness; depression; extraversion; mediation analysis; social network.