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Association Between Mental Health Status and Sleep Status Among Adolescents in Japan: A Nationwide Cross-Sectional Survey

Yoshitaka Kaneita, M.D.; Takashi Ohida, M.D.; Yoneatsu Osaki, M.D.; Takeo Tanihata, M.D.; Masumi Minowa, M.D.; Kenji Suzuki, M.D.; Kiyoshi Wada, M.D.; Hideyuki Kanda, M.D.; and Kenji Hayashi, M.D.

Objective: Previous epidemiological studies on relationships between mental health status and sleep status of adolescents have not been sufficiently representative. In the present study, using samples representative of Japanese adolescents nationwide, associations between mental health status and various sleep statuses were examined.

Method: The survey was conducted in December 2004 and January 2005 among students enrolled in randomly selected junior and senior high schools throughout Japan, using self-administered questionnaires that addressed lifestyle, sleep status, mental health status, and personal data. Of 103,650 questionnaires collected, 99,668 were analyzed. Sleep status was assessed according to sleep duration, subjective sleep assessment, bedtime, and insomnia symptoms. The Japanese version of the 12-item General Health Questionnaire was employed for assessment of mental health status.

Results: Mental health status of subjects whose sleep duration was less than 7 hours, and those who slept 9 hours or more, was poorer than that of subjects who slept for 7 hours or more but less than 9 hours. A U-shaped association was observed between mental health status and sleep duration. Furthermore, a linear association was observed between subjective sleep assessment and mental health status; the worse the subjective sleep assessment, the poorer the mental health status. Mental health status was also inversely proportional to the frequency of insomnia symptoms.

Conclusion: The fact that sleep duration and subjective sleep assessment showed different patterns of association with mental health status indicates that these 2 sleep parameters have independent significance. Considering these associations, it is important to promote mental health care and sleep hygiene education for adolescents.

(J Clin Psychiatry 2007;68:1426-1435)

Received Oct. 10, 2006; accepted Feb. 9, 2007. From the Department of Public Health, School of Medicine, Nihon University, Tokyo, Japan (Drs. Kaneita and Ohida); the Division of Environmental and Preventive Medicine, Department of Social Medicine, Faculty of Medicine, Tottori University, Yonago, Japan (Dr. Osaki); the Department of Epidemiology, National Institute of Public Health, Wako, Japan (Dr. Tanihata); the Faculty of Humanities, Seitoku University, Matsudo, Japan (Dr. Minowa); the Section on Behavioral Science, Division of Clinical Research, National Hospital Organization, Kurihama Alcoholism Center, Yokosuka, Japan (Dr. Suzuki); the Department of Drug Dependence Research, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Japan (Dr. Wada); the Department of Hygiene and Preventive Medicine, Fukushima Medical University, Fukushima, Japan (Dr. Kanda); and the Vice President, National Institute of Public Health, Wako, Japan (Dr. Hayashi).

This study was supported by a Health Science Research Grant from the Ministry of Health, Labor and Welfare of the Japanese Government (#H16-KENKO-024) to Dr. Hayashi.

The authors thank Professor Makoto Uchiyama, M.D., (Department of Neuropsychiatry, School of Medicine, Nihon University) for his very helpful suggestions. Dr. Uchiyama has no conflicts of interest to disclose.

The authors report no financial affiliations or other relationships relevant to the subject of this article.

Corresponding author and reprints: Yoshitaka Kaneita, M.D., Department of Public Health, School of Medicine, Nihon University, 30-1, Ohyaguchikami-machi, Itabashi-ku, Tokyo 173-8610, Japan (e-mail: