Pathways of Internalizing and Posttraumatic Stress Symptoms Across Childhood and Adolescence.

Research in adult populations has suggested a number of possible explanations for the high co-morbidity between posttraumatic stress symptoms (PTSS) and internalizing symptoms, including shared risk factors and reciprocal causation. Little research has examined these hypotheses in children or has considered the separation of between- and within-person effects. The objective of this study was to examine pathways between PTSS and internalizing symptoms using two samples drawn from the Longitudinal Studies on Child Abuse and Neglect (LONGSCAN, n = 1221) and the first National Survey of Child and Adolescent Well-Being (NSCAW-I, n = 309). Each sample included three waves of data (LONGSCAN: ages 8, 12, and 16; NSCAW: ages 8, 11, 15). It was hypothesized: (1) PTSS would predict future internalizing symptoms; (2) the strength of the relationship between internalizing symptoms and PTSS would increase over time; and (3) childhood trauma would be associated with higher levels of internalizing symptoms and PTSS. The hypotheses were examined using traditional cross-lagged panel models (CLPMs) as well as a CLPM with random intercepts (RI-CLPM), which has the advantage of separating within-person effects from between-person stability in symptoms. Results from both CLPMs and RI-CLPM support rising symptom comorbidity from late childhood to mid-adolescence. Results between the models, however, suggest that the reciprocal influence between symptom complexes over time may not hold after separating between- and within-persons effects, lending stronger support to the shared risk factors hypothesis and highlighting the need for future research to explore other possible explanatory mechanisms for the rising comorbidity of these symptom complexes over development.