Abstract: Previous studies have found temporal differences in posttraumatic stress disorder (PTSD) development. Clinical workers and researchers have also demonstrated that symptoms of PTSD differ by stage after traumatic events. Recently, the symptom network perspective has contributed substantially to the development of psychopathology due to its important advantage in understanding the role of psychological symptoms in mental disorders. An increasing number of analyses adopting the network approach to study PTSD symptoms have also provided novel insights into PTSD symptomatology. However, changes in children’s long-term PTSD symptomatology are poorly understood. The current study aims to identify changes in the network of PTSD symptoms among children through the network approach.
A four-year longitudinal study was conducted from 4 months after the Wenchuan earthquake. Four assessments were conducted at four (T1; September 2008), 29 (T2; October 2010), 40 (T3; September 2011) and 52 (T4; September 2012) months following the earthquake. Ultimately, 197 children completed assessments at each time point. The children were in grades four and six at T1 and attended two primary schools located in Beichuan County. Symptoms of PTSD were assessed by the University of California at Los Angeles PTSD Reaction Index based on the DSM-IV. Network analysis was implemented with the qgraph package in R following the standard guidelines by Epskamp and Fried.
Flashbacks exhibited relatively high centrality at all time points, while other symptoms with high centrality varied across time points. Emotional cue reactivity exhibited high centrality at 4 months, and its centrality decreased over time. Foreshortened future exhibited high centrality at 4, 29 and 40 months, but its centrality decreased to a low level at 52 months. Intrusive thoughts exhibited low centrality at 4 months, but the centrality of this symptom increased to a high level at 29 months. Physiological cue reactivity exhibited low centrality at 4 months, and its centrality increased over time. These findings indicated the distinct temporal variability in the centrality of some PTSD symptoms. The global connectivity of the network increased from 4 to 40 months and then decreased at 52 months.
The current study enhanced the knowledge of child PTSD symptomatology. Flashbacks might play a key role in the evolution of PTSD symptoms. In addition, different core symptoms might contribute to early and chronic PTSD structures. Emotional cue reactivity and foreshortened future might play key roles in early PTSD structures and then recover in later stages following disasters. Physiological cue reactivity and intrusive thoughts might be core symptoms in chronic PTSD structures. The phenomenon of the increased connectivity of the PTSD symptom network at 40 months may be one reason why previous trauma leads to vulnerability to PTSD. Overall, our study highlighted temporal differences in PTSD symptoms. Different core symptoms in early and chronic PTSD structures should be treated as targets at different stages following disasters in clinical practice.

Key words: posttraumatic stress symptoms, network approach, longitudinal study, developmental difference, symptomatology