Table 1.

Characteristics of included trials (k = 20) by date of publication

Trial citation	Program	N Age (years)	Control	Delivery	Content	Primary anxiety measure	Post-test effect size*	Follow-up effect size (months)
Kiselica et al. [41]	Stress inoculation	48 14–15	NI	MHP + school MHP	CBT	STAI A-TRAIT	− 0.74a	− 1.01 (1)c
Dadds et al. [36]	Coping koala	128 7–14	NI	MHP + Grad	CBT	RCMAS	0.01	− 0.05 (6)
Mifsud and Rapee [51]	Cool kids	91 8–11	WL	MHP + school MHP	CBT	SCAS	− 0.35	− 0.57 (4)c
Bernstein et al. [34, 54]	FRIENDS (child + parent)	61 7–11	FRIENDS child only + WL	MHP + Grad	CBT	MASCb	0.22	− − 0.04 (6)
Gillham et al. [39]	Penn resiliency program	44 11–13	NI	Grad/ researchers	CBT	RCMAS	− 0.07	− 0.62 (6)c − 0.79 (12)c
Siu [47]	FRIENDS	47 7–10	WL	MHP	CBT	SCARED	− 1.48a	NA
Hunt et al. [38]a	FRIENDS	260 11–13	NI	School MHP + Teacher	CBT	SCAS	No control group data	0.17 (24) − 0.01 (48)
Siu [48]	Theraplay	46 Mean 7.8	WL	MHP	Play therapy	Internalising scale of CBCL	− 2.40a	NA
Manassis et al. [37]	Feelings club	148 8–12	AC	MHP + Grad	CBT	MASCb	− 0.06	− 0.06 (12)
Liddle and Macmillan [43]a	FRIENDS	51 8–14	WL	MHP	CBT	SCAS	No control group data	NA
Cooley-Strickland et al. [35]	FRIENDS	93 8–12	WL	MHP + Grad	CBT	RCMAS	0.21	NA
Miller et al. [52]	FRIENDS	191 9–12	AC	Teacher + MHP/Grad	CBT	MASC	0.08	NA
Nobel et al. [45]	Feelings Club	78 8–11	AC	MHP	CBT	MASC	0.03	NA
McLoone and Rapee [44]	Cool Kids	152 7–12	Home + WL	School MHP	CBT	SCAS	− 0.43	− 0.27 (12)
Sportel et al. [33]; de Hullu et al. [55]	Cognitive Behavioural Group	240 12–16	CBT + NI	MHP	CBT	SP subscale of RCADSb	0.16	− 0.41 (6)c − 0.17 (12) − 0.21 (24)
Yulei et al. [50]	Cool Kids	59 14–17	WL	MHP + Grad	CBT	SCAS	− 0.45	NA
Hadwin et al. [40]	Cogmed-WM	40 11–14	AC	Computerised	WM training	RCMAS	− 0.46	0.00 (3)
Lam [42]	MBCT-C	20 9–13	WL	MHP + Grad	Mindfulness	RCADS	0.22	NA
Scholten et al. [46]	Dojo video game	138 11–15	AC	Computerised + researcher	ERT + HRV biofeedback	SCAS	− 0.11	0.03 (3)
Van Starrenburg et al. [49]	Coping Cat	141 7–13	WL	MHP + Grad	CBT	SCAS	− 0.58a	− 0.64 (3)c

Mode of delivery: MHP Mental health professional, Grad graduate students. Program content: CBT Cognitive behavioural therapy, MBCT-C mindfulness-based cognitive therapy for children, WM working memory, ERT + HRV emotion regulation training and heart rate variability. Control: WL wait list, NI no intervention, AC attention control. Anxiety outcome measures: RCADS Revised Children’s Anxiety and Depression scale, SCAS Spence Children’s Anxiety Scale, RCMAS Revised Children’s Manifest Anxiety Scale, SCARED The Screen for Child Anxiety-Related Disorders), STAI A-TRAIT State-Trait Anxiety Inventory, MAS Multidimensional Anxiety Scale for Children, CBCL Child Behaviour Checklist, SP subscale Social Phobia subscale. Follow-up effect sizes: NA not available (typically as waitlist controls had started the intervention by follow-up, so no true control group data available)

*Negative effect sizes indicate reduction in symptoms

^aExcluded from the meta-analysis

^bAlso administered post-intervention diagnostic interviews

^cSignificant differences in anxiety scores between intervention and control groups