Comparative study for managing OCD and anxiety symptoms (COSMOS) study: Rationale, design, and methods.

Anxiety and obsessive-compulsive disorders are common among children and adolescents and, if left untreated, can lead to further psychiatric morbidity and impairment. Practical barriers, such as financial constraints, limited availability of therapists, and time limitations of families, may impede access to evidence-based treatments. Low-intensity treatments show promise in addressing these barriers while conserving resources for those who require additional support. However, further empirical evidence is needed regarding the comparative efficacy of different interventions. To address this gap, we detail the protocol for a randomized controlled trial that compares the effectiveness of three different low-intensity therapy interventions - internet guided cognitive-behavioral therapy, parent-led treatment, and relaxation therapy - and explores the underlying mechanisms of each.