Mamoru Tochigi1, Satoshi Usami2, Misato Matamura3, Yuko Kitagawa3, Masako Fukushima4, Hiromi Yonehara4, Fumiharu Togo3, Atsushi Nishida5, Tsukasa Sasaki6. 1. Department of Neuropsychiatry, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-0003, Japan. 2. Faculty of Human Sciences, Department of Psychology, University of Tsukuba, 1-1-1 Ten-nodai, Ibaraki, Tsukuba 305-8572, Japan. 3. Department of Physical and Health Education, Graduate School of Education, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan. 4. The University of Tokyo Secondary School attached to the Faculty of Education, 1-15-1 Minamidai, Nakano, Tokyo 164-0014, Japan. 5. Department of Psychiatry and Behavioral Science, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo 156-8506, Japan. 6. Department of Physical and Health Education, Graduate School of Education, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan. Electronic address: psytokyo@yahoo.co.jp.
Abstract
OBJECTIVE: To investigate the longitudinal relationship between sleep habits and mental health in adolescents. METHODS: Multipoint observation data of up to five years were employed from a prospective cohort study of sleep habits and mental health status conducted from 2009 to 2013 in a unified junior and senior high school (grades 7-12) in Tokyo, Japan. A total of 1078 students answered a self-report questionnaire, including items on usual bed and wake-up times on school days, and the Japanese version of the 12-item General Health Questionnaire (GHQ-12). RESULTS: Latent growth model (LGM) analysis, which requires three or more time point data, showed that longitudinal changes in bedtime and GHQ-12 score (or score for depression/anxiety) were significantly and moderately correlated (correlation coefficient = 0.510, p < 0.05). Another result of interest was that, using an autoregressive cross-lagged (ARCL) model, bedtime and the depression/anxiety score had reciprocal effects the following year: ie, bedtime significantly affects the following year's depression/anxiety, and vice versa. In addition, the analysis provided estimates of mutually predicted changes: one-hour bedtime delay may worsen the GHQ-12 score by 0.2 points, and one-point worsening of the score may delay bedtime by 2.2 minutes. CONCLUSIONS: By using up to five multiple time point data, the present study confirms the correlational and reciprocally longitudinal relationship between bedtime delay and mental health status in Japanese adolescents. The results indicate that preventing late bedtime may have a significant effect on improving mental health in adolescents.
OBJECTIVE: To investigate the longitudinal relationship between sleep habits and mental health in adolescents. METHODS: Multipoint observation data of up to five years were employed from a prospective cohort study of sleep habits and mental health status conducted from 2009 to 2013 in a unified junior and senior high school (grades 7-12) in Tokyo, Japan. A total of 1078 students answered a self-report questionnaire, including items on usual bed and wake-up times on school days, and the Japanese version of the 12-item General Health Questionnaire (GHQ-12). RESULTS: Latent growth model (LGM) analysis, which requires three or more time point data, showed that longitudinal changes in bedtime and GHQ-12 score (or score for depression/anxiety) were significantly and moderately correlated (correlation coefficient = 0.510, p < 0.05). Another result of interest was that, using an autoregressive cross-lagged (ARCL) model, bedtime and the depression/anxiety score had reciprocal effects the following year: ie, bedtime significantly affects the following year's depression/anxiety, and vice versa. In addition, the analysis provided estimates of mutually predicted changes: one-hour bedtime delay may worsen the GHQ-12 score by 0.2 points, and one-point worsening of the score may delay bedtime by 2.2 minutes. CONCLUSIONS: By using up to five multiple time point data, the present study confirms the correlational and reciprocally longitudinal relationship between bedtime delay and mental health status in Japanese adolescents. The results indicate that preventing late bedtime may have a significant effect on improving mental health in adolescents.