Internet-Delivered Cognitive Behavioral Intervention for Youths With Anxiety Disorders

The goal of this study is to develop a new internet-delivered cognitive behavioral therapy (ICBT) intervention for youths with anxiety disorders based on the best current knowledge about effective cognitive behavioral therapy for the target group, refine the intervention in collaboration with patient and public representatives, and conduct a preliminary evaluation of the treatment effects in an open clinical trial. The primary objective of the study is: 1\. To evaluate the preliminary efficacy of a newly developed ICBT intervention for children and adolescents with anxiety disorders in reducing anxiety severity, as measured by the Pediatric Anxiety Rating Scale (PARS). Secondary objectives of the study are: 1. To examine the preliminary efficacy (PARS) of the ICBT intervention at 3 months post-treatment. 2. To examine how youths with anxiety disorders, their caregivers, therapists, and healthcare leadership experience the ICBT intervention. 3. To examine factors (e.g., age, type of anxiety disorder, presence of depressive symptoms, experiences of ICBT) that predict treatment outcome. 4. To examine how the ICBT intervention can be improved (e.g., treatment content and technical delivery) for future use. Participants will: * Undergo ICBT treatment for anxiety disorders during 12 weeks * Complete questionnaires at multiple time points throughout the study * Participate in follow-ups post-treatment and 3 months post-treatment * A selection of participants will also be invited to focus group interviews with the aim to generate ideas on how the intervention may be improved for future use