Participants in the planned therapist feedback iCBT condition will receive the iCBT intervention with planned feedback after each completed module. The therapist may spend a max. of 15 minutes giving feedback per module.

Participants in the on-demand therapist feedback iCBT condition will receive the intervention with on-demand feedback that is participant-initiated. The therapist may spend a max. of 15 minutes giving feedback per module.

CoolMinds consists of 11 adolescent sessions and 9 parent sessions to be completed simultaneously during a 14-week treatment period. The main components comprise psychoeducation, cognitive restructuring, exposure therapy, and relapse prevention. The parent program also comprises information on how to handle school absenteeism for parents and teachers or pedagogues. The intervention is mainly transdiagnostic within the anxiety disorders but also includes diagnosis specific modules and content allowing for more personalized treatment. The treatment is delivered via a telephone app but can also be accessed via computer.

An online diagnostic assessment tool that assesses DSM-5 anxiety disorders and specific phobias. Each present diagnosis is assigned a clinician-rated severity score ranging from 0 (minimal/absent) to 4 (pervasive). Typically subclinical disorders would receive a rating of 0 or 1, and clinical disorders a rating of 1 to 4.

A 44-item self-report questionnaire assessing anxiety symptoms of six different anxiety disorders in DSM-IV: generalized anxiety, panic/agoraphobia, social phobia, separation anxiety, obsessive compulsive disorder and physical injury fears. Symptoms are rated on a 4-point frequency scale ranging from 0 (never) to 3 (always) (min. = 0; max. = 114). A higher score indicates increased symptom severity. The Danish version has demonstrated good psychometric properties

CALIS measures the impact of youth anxiety on various areas of life functioning such as school, extracurricular activities, family life and friendships. Impact is reported on a 5-point severity scale ranging from 0 (not at all) to 4 (a lot) (min. = 0; max = 56). A summed score of all items is used to indicate level of impact, where a higher score indicates greater impairment. CALIS has shown satisfactory internal consistency and moderate test-retest reliability.

An 8-item questionnaire used to measure general satisfaction with a received treatment. Satisfaction is reported using a 4-point scale ranging from 1 (lowest degree of satisfaction) to 4 (highest degree of satisfaction). A summed score of all items is used to indicate level of satisfaction (min = 8; max. = 32). The scale has shown high internal consistency and concurrent validity.