Evaluation of Siblings’ Perceived Relationship Outcomes with Their Parents in an Open Trial of the SIBS Intervention for Children with Chronic Disorders

The SIBS intervention aims to prevent mental health problems for siblings of children with chronic disorders and has shown promising results. The mechanisms behind these changes have not been examined. Parent-child relationship quality is a predictor of mental health in siblings. Our first objective was to investigate whether sibling-perceived relationship quality between siblings and parents changes over time after participating in SIBS. Second, as the intervention requires participation of only one parent, we examined with a dual scale (anxiety and avoidance attachment style) whether relationship quality was associated with which parent participated. Third, as SIBS aims to promote parents‘ communication skills, we examined whether sibling-perceived communication quality with parents predicted relationship quality over time. The sample comprised 99 siblings (M = 11.5 years, SD = 2.0; range 8–16; 54% girls, 46% boys) of children with chronic disorders and one parent per sibling (63% mothers). We administered the questionnaires at pre-intervention, at three- and 6-months post-intervention. We applied growth curve models for relationship quality over time with communication quality as a predictor, controlling for parent gender. We found significant improvement in sibling-perceived relationship quality with the participating and the non-participating parent on the relationship anxiety scale over time, with small to medium effect sizes. Higher communication quality significantly predicted improvement of relationship quality in all four relationship outcomes. We conclude that change in relationship quality may be part of the positive outcomes of the SIBS intervention and is mainly explained by communication enhancement. Controlled trials of the SIBS intervention are indicated.