Objectives: Students' depressive symptoms might be related to their own risk factors and to their parents' status. The objective of this cross-sectional study was to examine the relationship of depressive symptoms with lifestyle variables and parents' psychological and socio-demographic status among Japanese junior high school students.
Methods: Of 477 students and their parents, 409 (85.7 %) students and 314 (65.8 %) parents participated in the study. Students answered self-reported questionnaire on depressive symptoms, their heights and weights, subjective stress, body dissatisfaction, lifestyles including sleep duration and extracurricular physical activity in school and other physical activity outside the school, and nutritional intake. Parents responded to questionnaire on depressive symptoms and socio-demographic status.
Results: The prevalence of depressive symptoms was 24.9 %. Students with depressive symptoms were more likely to have stress. Students in shorter and longer sleep duration groups were more likely to have depressive symptoms. The students with depressive symptoms had smaller amount of energy intake than did those without depressive symptoms. Multiple logistic regression analysis revealed significant relationships between students' depressive symptoms and some independent variables. Sex, subjective stress, "almost-never"-categorized extracurricular physical activity in school and other physical activity outside the school, and having a parent with depressive symptoms were significantly associated with students' depressive symptoms.
Conclusion: Reducing mental stress and taking care of lifestyles, especially, "almost-everyday"-categorized extracurricular physical activity in school and other physical activity outside the school, may have benefits for students' mental health, and having a parent with depressive symptoms may be associated with students' depressive symptoms.
Keywords: Adolescents; Depressive symptoms; Lifestyle; Mental health; Parent status; Stress.