Table 1.

Overview of inclusion criteria per screening phase

Included if:	Assessment
Screening phase 1
Elevated levels of social anxiety	SPIN questionnaire = total score ≥ 19 as a cut-off score
Fluency in Dutch	Able to complete the SPIN questionnaire + further assessed during the 2nd screening stage
Adolescents are 12–16 years old (they must be at least in their second semester of 1st grade of secondary school up until 5th grade)	Demographic questions during the SPIN administration
(Online) informed consent from adolescent and one of their legal guardians	Presence of the required informed assent and consent
Screening phase 2
No severe SAD	SAD diagnosis (SCID-5 Junior, Module 6D) + significant level of functional impairment (e.g., refusal to attend school) with ADIS-CSR = 8 (judged by the assessor)
No severe depression	Mood disorder diagnosis (SCID-5 Junior; Module 3B) + significant level of functional impairment with ADIS-CSR = 8 (judged by the assessor)
No severe substance use	Severe substance use based on the SCID-5 Junior (≥ 6 symptoms); Module 13
No presence of psychotic symptoms (regardless of severity)	Based on the screening questions of an adapted version of the SCID-5 Junior & ADIS-C / assessor’s judgment
No severe suicidal thoughts and / or self-harm	SCID-5 Junior screening questions + MINI-KID Module B on suicidality and self-harm / suicidality: severity rating of ≥ 9 and self-harm: (1) there is danger due to very serious injuries (e.g. deep cutting, which requires medical care) and/or (2) when one’s self harm behavior is combined with suicidal ideation
No other urgent psychopathologies and/or mismatch between participants’ clinical presentation and the offered training	Based on assessor’s judgment and then discussed during supervision
No use of psychoactive medication that has not been stabilized; use of benzodiazepines	Stabilized = (a) same type and dosage for at least the last 4 weeks; (b) must remain unchanged throughout the study
No autism spectrum disorder (ASD)	Pre-existing diagnosis of ASD
No current ongoing psychological treatment (or on a waiting list) for anxiety disorders and/or depression	Asked during assessment interview
No exposure therapy for SAD in the past two years	Asked during assessment interview
Not eligible for the use of virtual reality (VR) - History of severe motion sickness and / or experiencing symptoms of motion sickness during 3D movies Lack of stereoscopic vision or a balance problem that would hinder the VR experience; - History of seizures, seizure disorder or epilepsy	Asked during assessment interview
Not a member of the same household as another participant in the study	Asked during assessment interview
No missing (online) informed consent/assent from adolescent and one of his / her legal guardians