Shared or unique trajectories of PTSD and depression in children over time since an earthquake.

Posttraumatic stress disorder (PTSD) and depression are common outcomes in children and adolescents following natural disasters. However, because of the comorbidity of PTSD and depression, their mutual relationship affects their relative trajectories over time. Therefore, this study examined the joint trajectories of PTSD and depression and assessed their consistency over time. Using self-report questionnaires, we surveyed 303 children in the worst-affected area of the Ya'an earthquake at 6 months, 1 year, and 18 months post-disaster. Four latent joint trajectories of PTSD and depression were identified: a chronic depression-delayed PTSD symptoms group (n = 59, 19.5%), a chronic PTSD-delayed depressive symptoms group (n = 10, 3.3%), a low-symptoms group (n = 208, 68.6%), and a chronic depression-PTSD symptoms recovery group (n = 26, 8.6%). Companionship and affirmative value were more likely to be observed in the low-symptoms group. These findings illustrate that PTSD and depression development are heterogeneously distributed, and various types of social support fill different roles in differentiating distinct joint trajectories of PTSD and depression.