Background/Objectives: School refusal tendency is an important school adaptation issue, but its upstream psychosocial correlates remain insufficiently understood. We examined whether baseline multidimensional social interaction was prospectively associated with later school refusal tendency and whether an exploratory statistical indirect association was observed through psychological and behavioral difficulties. Methods: This three-year longitudinal observational study included 314 students in grades 5–9 aged ≥12 years at baseline in 2020 and followed through 2023. Social interaction was assessed using the Index of Social Interaction (ISI), psychological and behavioral difficulties using the parent-reported Strengths and Difficulties Questionnaire (SDQ), and school refusal tendency using a parent-reported binary item. Adjusted regression and Monte Carlo product-of-coefficients analyses were conducted. Results: School refusal tendency was observed in 84 participants (26.8%). Higher baseline ISI scores were associated with lower follow-up SDQ total difficulties (β = −0.830, 95% CI: −1.033 to −0.627) and lower odds of school refusal tendency (OR = 0.832, 95% CI: 0.741–0.934). The indirect effect through follow-up SDQ total difficulties was significant (−0.120, 95% CI: −0.193 to −0.055). After adjustment for baseline SDQ total difficulties, the indirect effect remained significant (−0.067, 95% CI: −0.124 to −0.020); Firth and parsimonious models yielded similar estimates. Baseline-domain-adjusted analyses retained indirect effects through emotional symptoms, peer problems, and internalizing problems. Conclusions: Higher baseline multidimensional social interaction was associated with lower subsequent psychological and behavioral difficulties and school refusal tendency. Baseline-SDQ-adjusted analyses supported an exploratory indirect association, particularly through internalizing-related difficulties; however, concurrent assessment of follow-up SDQ and school refusal precludes causal interpretation.

Home-rearing environments are integral to early childhood development. However, it remains unclear whether their developmental significance has changed over time. This study aimed to examine the temporal changes in home-rearing environments and their longitudinal associations with child developmental atypicality in Japan, using baseline assessments from 1999 to 2023 and follow-up assessments through 2024. Data were obtained from the Japanese Childcare Cohort Study, a nationwide childcare-based developmental surveillance project. The analysis included 40,627 1-year observation pairs of 18,210 children enrolled in childcare centers. Home-rearing environments were assessed using the Index of Child Care Environment, and developmental atypicality was evaluated using the Child Development Scale across six domains. Logistic regression models were used to examine the associations between baseline home-rearing environments and developmental atypicality 1 year later, adjusting for baseline developmental status, sex, and age. Generalized additive models and rolling-window analyses were used to assess temporal trends and time-varying associations. Overall, the Index of Child Care Environment scores increased gradually throughout the study period, although social stimulation declined after the mid-2010s. Higher-quality home-rearing environments were generally associated with a lower risk of subsequent developmental atypicality. Protective associations strengthened over time, particularly in the social, communication, vocabulary, and intellectual domains. Home-rearing environments and their developmental implications changed over the 25-year observation period. These findings highlight the continued importance of promoting direct caregiver–child interactions, including shared activities and social engagement. Early childhood surveillance should be periodically re-evaluated to remain relevant to evolving caregiving practices and family contexts.