The relationship between post-traumatic stress and depressive symptoms in children: A two-year longitudinal study

Abstract

Studies have shown that children and adolescents exposed to natural disasters could be at high risk of mental health problems. Post-traumatic stress disorder (PTSD) is now well established as the most common psychopathological outcome of trauma. Studies have shown that PTSD often co-occurs with depression. The comorbidity of PTSD and depression adversely affects the hospitalization of patients. The high prevalence of PTSD and depression poses challenges for accurate diagnosis and treatment. Therefore, the potential mechanism of the comorbidity of PTSD and depression deserves attention. Researchers have proposed several models of comorbidity, such as the "demoralization model," which indicates that the initial PTSD symptoms may cause subsequent depression. Conversely, the "depressogenic effect model" suggests that the initial depression may cause the subsequent PTSD. However, the "synchronous change model" posits that PTSD and depression occur at the same time and are independent of each other. Clearly, a consistent conclusion has not been reached. Therefore, the relationship between PTSD and depression should be further explored. Moreover, there are some limitations in previous studies. For example, the majority of these studies have focused on PTSD symptoms as a whole, without distinguishing PTSD symptom clusters (such as re-experiencing, avoidance, and hyperarousal) with depression over time. In addition, the most recent studies focused on adults. Children and adolescents are in the developmental stage of cognitive nervous system and emotional regulation and lack the coping mechanism for adaptation and recovery from a disaster. Therefore, they may be vulnerable to environmental changes and negative life events. In view of this, the comorbidity of PTSD and depression needs to be explored in children. The present study investigates the relationship between depressive symptoms and PTSD and differences between the relationships of PTSD clusters and depression among children who survived the Zhouqu debris flow. PTSD was measured with the University of California at Los Angeles Post-traumatic Stress Disorder Reaction Index for DSM-IV, and depressive symptoms were measured with the Children's Depression Inventory. Participants were assessed at 3, 15, and 27 months after the Zhouqu debris flow. The sample consisted of 1070 adolescents (aged 13.90±1.33), among which 452 (42%) were male and 618 (58%) were female. A cross-lagged analysis revealed bidirectional associations between PTSD and depressive symptoms from T1 to T2, and only depressive symptoms predicted PTSD significantly from T2 to T3. The relationships between depressive symptoms and three PTSD clusters were also different. From T1 to T3, depressive symptoms predicted three PTSD clusters continuously. However, avoidance had no predictive effect on depression from T1 to T3, re-experiencing predicted depressive symptoms from T1 to T2, and hyperarousal demonstrated a continuous predictive effect on depression from T1 to T3. Our study suggested that the relationship between depressive symptoms and PTSD may change over time and the relationships between the three clusters of PTSD and depression may be different. Psychological therapy should focus on different symptoms based on the trauma stage. Future studies should compare the relationships between depressive symptoms and PTSD across different courses after trauma, trauma types, genders, and age stages.