Bidirectional associations between insomnia, posttraumatic stress disorder, and depressive symptoms among adolescent earthquake survivors: a longitudinal multiwave cohort study.

STUDY
OBJECTIVES: To assess insomnia symptoms in adolescents with probable posttraumatic stress disorder (PTSD) and to determine whether there are longitudinal and reciprocal associations between insomnia, PTSD, and depressive symptoms.
METHODS: Participants were 1,492 adolescent survivors who had been exposed to the 2008 Wenchuan earthquake in China. Insomnia, PTSD, and depressive symptoms were measured at 12 months (T1, n = 1407), 18 months (T2, n = 1335), and 24 months (T3, n = 1361) postearthquake by self-report questionnaires. Generalized estimating equation (GEE) models were used to examine the cross-sectional and longitudinal associations of insomnia with PTSD and depression.
RESULTS: Insomnia, PTSD, and depressive symptoms were common among adolescent survivors. Among participants with probable PTSD, approximately 47% (48.5%, T1; 48.1%, T2; and 44.2%, T3) reported difficulty falling asleep or difficulty maintaining sleep. Cross-sectional analyses showed that insomnia co-occurred with PTSD (odds ratio [OR] = 2.04) and depressive symptoms (OR = 2.10). Longitudinal analyses revealed that probable PTSD (OR = 1.50) and depression (OR = 1.42) predicted the incidence of insomnia; in turn, insomnia predicted the incidence of depression (OR = 1.65) over time. Furthermore, PTSD predicted (OR = 3.11) and was predicted (OR = 3.25) by depressive symptoms.
CONCLUSIONS: There is a bidirectional relationship between insomnia, PTSD, and depressive symptoms. This suggests that insomnia, PTSD, and depression are intertwined over time. © Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.