Stepped Versus Stratified Care for Anxiety Disorders in Youth

The goal of this clinical trial is to compare stepped care to stratified care as overall healthcare models for children and adolescents aged 8-17 with anxiety disorders. It addresses one main question:

• Is stepped care non-inferior to stratified care in supporting participants to achieve a treatment response?

Researchers will compare two care models:

* Stepped care, where all participants begin with 14 weeks of internet-delivered cognitive behavioral therapy (ICBT) and receive an additional 14 weeks of personalized in-person CBT if needed.
* Stratified care, where participants are assigned to either 14 weeks of ICBT or 14 weeks of in-person CBT based on clinical complexity, and may also receive additional 14 weeks of in-person CBT if necessary.

Participants will:

* Be randomly assigned to one of the two care models.
* Complete a wide range of assessments at baseline, during treatment, and at 4, 8, 12, and 24 months, with the 8-month point as the primary endpoint.
* Receive either ICBT, in-person CBT, or both, depending on their care model and response to treatment.
* Participate in ancillary studies involving DNA sampling, cognitive testing, and national registry linkages to help predict treatment response and long-term outcomes.

A detailed description is available in the full study protocol. All study protocol versions can be accessed at the Open Science Framework (https://osf.io/a9qhw/).

Eligibility Criteria:
Inclusion Criteria:

1) 8 to \<18 years of age.

* Confirmed by the child and/or caregiver. 2) Principal DSM-5-TR anxiety disorder of social anxiety disorder, generalized anxiety disorder, panic disorder, separation anxiety disorder, specific phobia, or agoraphobia.
* Confirmed by the structured diagnostic interview (DIAMOND-KID). "Principal" indicates that the anxiety disorder is judged by the clinician to be in most urgent need of treatment (among potential co-occurring disorders).

  3) Available caregiver who can support the child in treatment.
* Confirmed by the caregiver. 4) Child and at least one caregiver can read, write, and communicate in Swedish.
* Confirmed by the child and/or caregiver. 5) Child (≤13 years) and caregiver have access to a Swedish electronic identification (BankID or Freja eID).

  6) Access to the internet.
* Confirmed by the child and/or caregiver. 7) Ability to attend in-person CBT sessions at the clinic.
* Confirmed by the child and/or caregiver.

Exclusion Criteria:

1) Principal DSM-5-TR anxiety disorder of specific phobia concerning the domain of blood-injection-injury (due to the ICBT program not including relevant information on applied-tension techniques to avoid fainting during exposure exercises).

* Confirmed by a specific phobia of this sort being classified as the most functionally impairing anxiety disorder during the structured diagnostic interview (DIAMOND-KID).

  2) Ongoing psychological treatment for an anxiety disorder.
* Confirmed by the child and/or caregiver. 3) Social/familial/educational difficulties in more immediate need of management than an anxiety disorder.
* Confirmed by the assessor through information from the child and/or caregiver and/or other available sources.

  4) Immediate risk to self or others that require urgent attention, such as suicidality.
* Confirmed by the assessor through information from the child and/or caregiver and other available sources.

  5) The potential participant has a relative (e.g., sibling, cousin) included in the study.
* Confirmed by the assessor through information from the caregiver and other available sources.