One-year course and effects of insomnia in rural Chinese adolescents.

STUDY OBJECTIVES: We aimed to explore the incidence and persistence of insomnia, the associated risk factors, and the potential bidirectional association of insomnia with depression, anxiety, and sleepiness in rural Chinese adolescents. DESIGN: School-based prospective study. SETTING: Five high schools in rural China. PARTICIPANTS: There were 2,787 adolescents studied. INTERVENTIONS: N/A. MEASURES AND RESULTS: Insomnia was defined as having a score of equal to or higher than nine in the Insomnia Severity Index as validated in Chinese adolescents. Depression, anxiety, and sleepiness were determined by the Beck Depression Inventory (BDI), Zung Self-Rating Anxiety Scale (SAS), and Epworth Sleepiness Scale (ESS), respectively. The incidence and persistence rates of insomnia were 16.0% and 41.0%, respectively. Multivariate analyses in logistic regression models revealed that new incidence of insomnia was significantly associated with age, living in a rural area, habitual daytime napping, high life events, anxiety, and depression at baseline (range adjusted odds ratio = 1.12-1.61), whereas the persistence of insomnia was positively associated with age, female sex, high life events, and depression at baseline (range adjusted odds ratio = 1.26-1.55) but negatively associated with living in a rural area (odds ratio = 0.59). Insomnia at baseline could predict new onsets of both depression (odds ratio = 1.45) and anxiety (odds ratio = 1.98) but not sleepiness at follow-up after adjustment for age, sex, and baseline symptoms. The results in cross-lagged analyses further supported these observations in the bidirectional associations of insomnia with depression, anxiety, and sleepiness. CONCLUSIONS: Insomnia has considerable incidence and persistence rates in Chinese adolescents. We have identified several risk factors for the incidence and persistence of insomnia. There are bidirectional associations of insomnia with depression and anxiety but not sleepiness. CITATION: Luo C; Zhang J; Pan J. One-year course and effects of insomnia in rural Chinese adolescents. SLEEP 2013;36(3):377-384.