Siblings of children with CDs are at increased risk of developing mental health problems. The risk is observed at the group level, and does not apply to all siblings. More knowledge about what impacts the risk for siblings is needed. There is also insufficient knowledge about effective healthcare services to prevent the potential development of mental health problems among siblings. The overarching aim of this thesis was to provide insight into predictors of siblings’ mental health, to identify those in need of support and to help pinpoint key factors in interventions.
SIBS is a manual-based intervention aiming to prevent mental health problems in siblings. The research in this thesis is based on two studies on SIBS: the SIBS open trial and the SIBS-RCT. The data were primarily analyzed using regression analyses in Papers 1 and 3 and growth curve analyses in Paper 2. Paper 1 addresses two research questions: What factors predict the mental health status of these siblings? and Are there differences in these predictors based on whether the reported data involves the mother or the father? The suggested predictors were parental mental health, parent-child communication, parent-child relationship quality and sibling adjustment. The findings indicated that perceived relationship quality and how siblings adjust to having a brother or sister with a CD were significant predictors. Hence, the first research question was answered by showing that two of the four suggested predictors were significant. The results in Paper 1 further showed that siblings reported better relationship and communication with mothers than with fathers and that and mothers’ report about sibling mental health seemed more influenced by their own mental health than was the case with the fathers. Hence the second research question about possible differences between mothers and fathers in relation to siblings’ mental health was partly supported by the data.
Paper 2 focused on evaluating communication and relationship quality as outcomes following participation in the SIBS program. The research questions in Paper 2 explored whether siblings’ perceived relationship quality with the participating parent and the non-participating parent improved over time and whether perceived communication quality with their parent predicts relationship quality over time. The results of Paper 2 showed that siblings’ perceived relationship quality improved over time, from before to after participation in the SIBS intervention, but only in one of the relationship factors (anxiety). This applied to both the participating and the non-participating parent. Hence, the first hypothesis was partly supported. The second hypothesis of siblings’ perceived communication predicting a change in relationship quality over time was supported.
Paper 3 examines whether various diagnostic categories predict sibling mental health and whether parent-reported severity of the chronic disorder predicts sibling mental health. The results of Paper 3 showed that no single diagnostic category predicted sibling mental health, but that it was predicted by parents’ reports on symptom severity (in the child with a CD).
The findings from these three papers indicate that the quality of relationships and siblings’ adjustment to having a brother or sister with a CD are important predictors of siblings’ mental health, along with parents’ assessment of the severity of symptoms in the diagnosed child. Mothers and fathers may play different roles for siblings. The SIBS intervention, with its focus on improving communication skills, could have a positive influence on siblings’ perceived relationship quality. While these findings provide an indication of key predictors of siblings’ mental health, it is essential to consider them in conjunction with results from other studies and to consider how the various predictors interact.
The main limitations of these studies concern the representativeness of the samples in both the SIBS open trial and the SIBS-RCT. It is therefore unclear to whom the findings can be generalized. Additionally, there was no control group in the SIBS open trial (Papers 1 and 2), so the finding in Paper 2 of a change over time in relationship quality cannot be interpreted as an effect of the SIBS intervention. Future research on predictors of mental health in siblings should aim to obtain representative samples, particularly by including fathers and families who generally do not participate in research or treatment programs, often due to a lack of resources to prioritize this in their challenging daily life. Furthermore, research should explore relationship quality as a potential predictor in SIBS-RCT and emphasize factors that could improve relationship quality in the further development of interventions. A transdiagnostic approach in interventions may be appropriate.