Tol 2008.

Methods	Cluster‐randomised trial of a group‐based CBT intervention vs wait list
Participants	Included (n = 403) Children attending randomly selected schools in violence‐affected communities were screened for exposure to ≥ 1 violent event, scored ≥ 12 on the PTSD scale and ≥ 5 on the anxiety scale Mean age: 9.94 years. Female: 196. Mean number of violent exposures: 3.9 Excluded Considered unable to function in a group setting, including aggression, mutism, mental retardation, substance abuse, dissociative disorders, unmedicated epilepsy, panic or phobic disorders, child psychosis Setting Fourteen schools in Central Sulawesi Indonesia, 2006
Interventions	Intervention (n = 182) Manualised, school‐based intervention that integrates CBT techniques over 15 sessions in 5 weeks to groups of approximately 15 children. Sessions included psychoeducation, trauma‐processing activities, cooperative play and creative/expressive elements Control (n = 221) Wait list control group Therapists Locally trained paraprofessionals who had been selected for their social skills and received 2 weeks of training. Adherence was rated as 90%
Outcomes	PTSD symptoms Scale: Child Post‐Traumatic Stress Scale (17‐item) Rater: child Depression Scale: Depression Self‐Rating Scale (8‐item) Rater: child Anxiety Scale: Self‐Report for Anxiety‐Related Disorder (SCARED‐5; 5 items) Rater: child Behaviour Scale: Children’s Aggression Scale for Parents (33‐item) Rater: parent Function Scale: Functional impairment (10‐item) Rater: child, parent When At 1 week and 6 months
Notes	Functional impairment change scores were analysed as positive values to assess improvement in function
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants (performance bias	High risk	Participants probably were aware of whether they were in the active or wait list group
Blinding of outcome assessment (detection bias) All outcomes	High risk	Observers were not blinded, but all measures were child reported or parent reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Last observation carried forward analysis was used. Loss to follow‐up was low: 1 week 3%, 6 months 9%
Selective reporting (reporting bias)	Low risk	All outcomes appear to have been reported
Other bias	High risk	Displacement was higher in the control group (75%) than in the intervention group (37%)