Anxiety symptom trajectories from treatment to 5- to 12-year follow-up across childhood and adolescence.

OBJECTIVE: The current study examined trajectories of anxiety during (a) acute treatment and (b) extended follow-up to better characterize the long-term symptom trajectories of youth who received evidence-based intervention for anxiety disorders using a person-centered approach. METHOD: Participants were 319 youth (age 7-17 years at enrollment), who participated in a multicenter randomized controlled trial for the treatment of pediatric anxiety disorders, Child/Adolescent Anxiety Multimodal Study, and a 4-year naturalistic follow-up, Child/Adolescent Anxiety Multimodal Extended Long-term Study, an average of 6.5 years later. Using growth mixture modeling, the study identified distinct trajectories of anxiety across acute treatment (Weeks 0-12), posttreatment (Weeks 12-36), and the 4-year-long follow-up, and identified baseline predictors of these trajectories. RESULTS: Three nonlinear anxiety trajectories emerged: "short-term responders" who showed rapid treatment response but had higher levels of anxiety during the extended follow-up; "durable responders" who sustained treatment gains; and "delayed remitters" who did not show an initial response to treatment, but showed low levels of anxiety during the maintenance and extended follow-up periods. Worse anxiety severity and better family functioning at baseline predicted membership in the delayed remitters group. Caregiver strain differentiated short-term responders from durable responders. CONCLUSIONS: Findings suggest that initial response to treatment does not guarantee sustained treatment gains over time for some youth. Future follow-up studies that track treated youth across key developmental transitions and in the context of changing social environments are needed to inform best practices for the long-term management of anxiety.