Preference for solitude paradox: The psychological influence of social isolation despite preference

Background: Although a preference for solitude (PS) may mitigate the negative effects of social isolation (SI) owing to the enjoyment of time alone, its impact on mental health and its underlying factors remain unclear. Methods: An Internet survey was conducted with 9000 individuals aged 20-79 years in September 2023 and the analyses were performed across three generations. SI was defined as contact with non-cohabitating family members or relatives and friends/neighbors less than once a week. The PS scale, which was used to assess whether a person preferred spending time alone, stratified respondents into three PS-level groups. Mental health status was evaluated using the K6 (distress symptoms), the WHO-5 (well-being), and the UCLA Loneliness Score (severity of loneliness) as the main outcomes. The mediation analyses assessed whether troublesomeness in socializing, a potential negative aspect of PS, could explain the association between PS and mental health status. Results: A mixed-design two-way analysis of covariance showed that both SI and PS had significant main effects on all outcomes without interactions across generations, indicating that SI and higher PS were associated with poor mental health status. The association between higher PS and poor mental status was mediated by socializing troublesomeness across generations. Limitations: The cross-sectional design prevented making causal inferences from the results. Additionally, sampling bias from Internet surveys may limit the generalizability of the results. Conclusions: The results confirmed that there is no protective effect of PS on social isolation-related poor mental health. The hassle of socializing may partly explain why people with a higher PS experience poor mental status, including greater loneliness.