First‐year changes in mental health, lifestyle behaviors, and social support among international students at a Japanese university

Aim International students experience psychological distress due to cultural adjustment, loneliness, and limited social support. However, longitudinal evidence remains scarce in Japan, and comprehensive models incorporating lifestyle and social factors remain underexamined. This study investigated the changes in mental health symptoms, lifestyle behaviors, and social support during international students' first year after university enrollment. Furthermore, we examined longitudinal changes and their associations with academic year repetition. Methods This study included 216 international students who enrolled between 2016 and 2024. They completed questionnaire surveys upon university enrollment and 1 year later. Measures included the Kessler Psychological Distress Scale (K6), suicidal ideation, interpersonal tension, sleep duration, and number of available social supporters. Changes from baseline to 1‐year later were examined. Univariable logistic regression analyses were performed with academic year repetition as the outcome and baseline variables and variables that changed as predictors. Results Of the participants, 1.9% exhibited severe psychological distress (K6 ≥ 13 points) and 15.9% reported suicidal ideation at enrollment. Psychological distress did not significantly change over the first year. However, significant changes were observed in both weekend sleep duration ( χ 2 = 28.452, p < 0.001) and weekday sleep duration ( χ 2 = 6.838, p = 0.033), fewer available supporters ( Z = 2.757, p = 0.006), and reduced interpersonal tension ( Z = 2.549, p = 0.011). Furthermore, an increase in weekend sleep duration was associated with academic year repetition (odds ratio [OR] = 3.131, p = 0.027). Reduced interpersonal tension exhibited a trend toward lower repetition risk (OR = 0.131, p = 0.052). Conclusion Monitoring changes in sleep duration and interpersonal tension after enrollment may enhance academic and mental health support for international students.