Table 1.

Randomised controlled trial inclusion criteria*

1	Children ≤18 years of age were the main focus or were clearly reported on separately if part of an adult study.
2	Interventions aimed to prevent or treat anxiety disorders.
	a. For prevention, at enrolment/pretest, <50% had a primary anxiety disorder diagnosis.
	b. For treatment, at enrolment/pretest, ≥50% had a primary anxiety disorder diagnosis.
3	Clear descriptions were provided of participant characteristics, study settings and interventions.
4	Participants (or clusters) were randomly assigned to intervention and either control (no-intervention) or comparison (minimal intervention) groups at study outset.
5	Outcome measures pertained to anxiety, for example, scales had established reliability and validity or ≥50% of items addressed anxiety symptoms.
6	Anxiety indicators included either 1 diagnostic measure where the diagnostician was blinded or 2 symptom measures evaluated by 2 or more informant sources, for example, child, parent or teacher, at least one of whom was blinded.
7	Maximum attrition was 20% at post-test (medication studies) or at follow-up (prevention or psychosocial treatment studies) or authors used intention-to-treat analyses.
8	For prevention and psychosocial treatment studies, postintervention follow-up was 3 months or more.
9	For medication studies, double-blinding and placebo controls were used, and side effects were comprehensively assessed.
10	Statistical significance (using p<0.05) was reported for relevant outcome measures at post-test (medication studies) or at follow-up (prevention and psychosocial treatment studies).
11	Interventions were evaluated in high-income countries (by World Bank standards).
12	Studies focused on populations and settings with applicability to most children who may be at risk of or who may have anxiety, rather than specialised subpopulations.

*For inclusion, all criteria had to be met.