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.