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

Objective: Previous epidemiological studieson relationships between mental health status andsleep status of adolescents have not been sufficientlyrepresentative. In the present study, usingsamples representative of Japanese adolescentsnationwide, associations between mental healthstatus and various sleep statuses were examined.

Method: The survey was conducted in December2004 and January 2005 among students enrolledin randomly selected junior and senior highschools throughout Japan, using self-administeredquestionnaires that addressed lifestyle, sleep status,mental health status, and personal data. Of103,650 questionnaires collected, 99,668 wereanalyzed. Sleep status was assessed according tosleep duration, subjective sleep assessment, bedtime,and insomnia symptoms. The Japanese versionof the 12-item General Health Questionnairewas employed for assessment of mental healthstatus.

Results: Mental health status of subjectswhose sleep duration was less than 7 hours, andthose who slept 9 hours or more, was poorer thanthat of subjects who slept for 7 hours or more butless than 9 hours. A U-shaped association wasobserved between mental health status and sleepduration. Furthermore, a linear association wasobserved between subjective sleep assessmentand mental health status; the worse the subjectivesleep assessment, the poorer the mental healthstatus. Mental health status was also inverselyproportional to the frequency of insomniasymptoms.

Conclusion: The fact that sleep durationand subjective sleep assessment showed differentpatterns of association with mental health statusindicates that these 2 sleep parameters have independentsignificance. Considering these associations,it is important to promote mental healthcare and sleep hygiene education foradolescents.’ ‹