Changes in individual PTSD symptoms among youth in trauma treatment.

Background: Even though evidence-based treatment is generally effective in reducing posttraumatic stress disorder (PTSD) among youth, many still experience elevated symptoms after treatment. A better understanding of how PTSD develops through treatment can increase treatment efficiency and reduce residual symptoms. Objective: The current study investigated which PTSD symptom clusters and symptoms within these clusters that change the most and least through trauma-focused cognitive behavioral therapy (TF-CBT) and identified common residual symptoms after treatment. Method: Latent growth curve modelling was used to identify differences in intercepts and slopes of symptoms, and residual symptoms were identified with McNemar tests in a sample of 517 youth (6 -19 years, 75.6% girls) receiving TF-CBT. Results: We found small but statistically significant differences in slopes across clusters. Avoidance both reduced the most and demonstrated most residual symptoms. Also, within clusters, many of the symptoms that reduced the most, such as psychological cue reactivity, persistent negative emotional state, and difficulties sleeping and concentrating, had the highest symptom levels at pretreatment and the most residuals posttreatment. Conclusions: Overall, symptoms of PTSD were reduced throughout TF-CBT. Symptoms that were rated highest at treatment start showed the most decrease but also tended to remain as common residuals. Symptoms such as psychological cue reactivity, persistent negative emotional state, and negative beliefs that were common residuals and are known to be central in development and maintenance of PTSD are of particular clinical relevance. Elaborate research on short-term symptom development and mechanisms of change is needed to advance the field.