Internet-Delivered Cognitive Behavioral Intervention for Youths With Anxiety Disorders

Inclusion Criteria: 1\) 8 to \<18 years of age. * Confirmed by the child/caregiver and subsequently by the medical record system. 2) A principal DSM-5-TR anxiety disorder of specific phobia, separation anxiety disorder, social anxiety disorder, generalized anxiety disorder, panic disorder or agoraphobia. * Confirmed by the Diagnostic Interview for Anxiety, Mood, and OCD and related Neuropsychiatric Disorders - Child and Adolescent Version (DIAMOND-KID). 3\) Child and caregiver able to read, write and communicate in Swedish. * Confirmed by the child/caregiver. 4) An available caregiver who can support the child in treatment. * Confirmed by the caregiver. 5) Access to a smartphone, tablet, or laptop/desktop device, and the internet. * Confirmed by the child/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 blood-injection-injury phobia being classified as the principal anxiety disorder as assessed by the DIAMOND-KID. 2\) Established or suspected intellectual disability. * Confirmed by the caregiver (through previous diagnosis) and/or by attending a special needs school for learning difficulties. 3\) Another mental disorder in more immediate need of management than an anxiety disorder (e.g., schizophrenia spectrum and other psychotic disorders, bipolar disorder, anorexia nervosa, substance use disorders). * According to the DIAMOND-KID and/or other available sources. 4) Social/familial/educational difficulties in more immediate need of management than an anxiety disorder. * Confirmed by the assessor through information from the child/caregiver and/or other available sources. 5\) Immediate risk to self or others that require urgent attention, such as acute suicidality. * Confirmed by the assessor through information from the child/caregiver and other available sources. 6\) Previous CBT for an anxiety disorder, defined as five or more sessions with a certified CBT therapist within the 12 months prior to assessment. * Confirmed by the child/caregiver or the medical record system. 7) Ongoing psychological treatment for an anxiety disorder. * Confirmed by the child/caregiver or the medical record system. 8) Initiation or adjustment of any psychotropic medication for anxiety (i.e., selective serotonin reuptake inhibitors, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitor or antipsychotics) within 8 weeks prior to assessment. * Confirmed by the child/caregiver or the medical record system. 9) Participation in user involvement sessions in the present study. * Confirmed by the researcher.