Effectiveness of a group intervention to improve mental health in siblings of children with chronic disorders: a cluster randomized controlled trial

Objective We evaluated the effectiveness of SIBS, a preventive intervention for siblings and parents of children with chronic disorders (CDs).Methods This two-arm, unmasked cluster randomized controlled trial registered on ClinicalTrials.gov (NCT04056884), included 288 siblings (M age = 10.4 years, SD = 1.9) and parents of children with CDs (mainly neurodevelopmental disorders) randomly assigned to intervention (k = 34, n = 137) or waitlist control (k = 35, n = 151) groups. Eligible siblings were aged 8-16 years and had a sibling diagnosed with a CD. SIBS is manual-based and was delivered as five sessions over 2 weeks in primary care and hospital settings across Norway. Three sessions are separate for siblings and parents, and two are integrated sibling-parent dialogues. The primary outcome was sibling mental health, rated by siblings, parents, and teachers. The secondary outcome was parent-child communication, rated by siblings and parents. Analyses included intention-to-treat (ITT) and complier average causal effects (CACE).Results Although not statistically significant, at 3-month follow-up, the intervention group showed fewer mental health problems (ITT: sibling-rated d = -0.16, 95% CI [-0.49, 0.17]; parent-rated d = -0.10, 95% CI [-0.48, 0.12]; teacher-rated d = -0.18, 95% CI [-0.50, 0.29]) and higher-quality parent-child communication (ITT: sibling-rated d = 0.21, 95% CI [-0.10, 0.52]; parent-rated d = 0.24, 95% CI [-0.07, 0.55]) compared to waitlist.Conclusions The SIBS intervention demonstrated small, consistent positive effects on sibling mental health and parent-child communication. This suggests SIBS is a promising preventive program for siblings of children with CDs.