Factors behind solitude leading to poor mental health in older adults: is the preference for solitude an adaptation to social difficulties?

OBJECTIVES: This study explored the longitudinal association among preference for solitude (PS), social interactions, and mental health. METHODS: Data from the 2021 and 2023 waves of the Otassha Cohort Study involving 391 community-dwelling older adults in Tokyo were analyzed. The PS, social network size (Lubben social network scale (LSNS-6)), socializing difficulties, and mental health (geriatric depression scale (GDS) and WHO-5) were measured. RESULTS: Cross-lagged panel analyses assessing longitudinal associations revealed no direct link between the baseline PS and subsequent GDS scores. However, the baseline GDS and LSNS-6 scores were associated with all follow-up variables, and poorer values were correlated. A higher PS predicted lower LSNS-6 scores at follow-up, indicating a bidirectional association. Higher baseline PS was also associated with socializing difficulties at follow-up; however, baseline socializing difficulties were not. Similar trends were observed for the WHO-5, except that higher baseline PS was directly associated with lower WHO-5 at follow-up, and lower baseline WHO-5 only predicted subsequent socializing difficulties. CONCLUSION: Our findings suggest that PS is prospectively associated with lower well-being and indirectly associated with more depressive symptoms via lower structural social connectedness. PS may both contribute to and reflect changes in mental health and social connectedness, consistent with a 'rationalized preference' pathway under psychosocial constraints.