Associations between sleep disturbance and mental health status: A longitudinal study of Japanese junior high school students

Background: A limited number of longitudinal studies have addressed the association between sleep disturbance and mental health status among adolescents. To examine whether each of these is a risk factor for the onset of the other, we conducted a prospective longitudinal study of Japanese adolescents. Methods: In 2004, we performed a baseline study of students attending three private junior high schools in Tokyo, and in 2006, a follow-up study was performed on the same population. The mean age of the subjects was 13 years. The Pittsburgh Sleep Quality Index was used to evaluate sleep disturbance, and the 12-item General Health Questionnaire was used to evaluate mental health status. Results: The subjects were 698 students, of whom 516 were suitable for analysis. The incidence of newly developed poor mental health status during the 2 years leading to the follow-up study was 35.1%. New onset of poor mental health status was significantly associated with new onset of sleep disturbance and lasting sleep disturbance. The incidence of sleep disturbance during the 2 years leading to the follow-up study was 33.3%. New onset of sleep disturbance was significantly associated with new onset of poor mental health status and lasting poor mental health status. Conclusions: Sleep disturbance and poor mental health status increase each other's onset risk. (C) 2008 Elsevier B.V. All rights reserved.