This study examined the mental health of siblings of children with physical illness (PI), with or without co-occurring mental illness.
The sample included children aged 2 to 16 years with a chronic PI and their aged-matched healthy siblings (n = 169 dyads). Physical–mental comorbidity (PM) was present if children screened positive for ≥1 mental illness on the Mini International Neuropsychiatric Interview for Children and Adolescents. Parents completed the Strengths and Difficulties Questionnaire (SDQ) to measure child and sibling mental health.
Within child–sibling dyads, siblings of children with PI had significantly worse mental health related to conduct problems (d = 0.31), peer problems (d = 0.18) and total difficulties (d = 0.20). Siblings of children with PM had significantly better mental health related to emotional problems (d = 0.42), hyperactivity/inattention (d = 0.23) and total difficulties (d = 0.32). Siblings of children with PI had similar mental health compared with child population norms used in the development of the SDQ. In contrast, siblings of children with PM had significantly worse mental health across all SDQ domains, with the exception of prosocial behaviour. After adjusting for parent psychopathology and family functioning, no statistically significant differences between siblings of children with PM versus siblings of children with PI were found.
Differences in mental health exist between children with PI or PM versus their healthy siblings. However, differences between siblings of children with PI versus siblings of children with PM can be explained by parental and family factors (e.g. marital status, education and income). Findings reinforce family-centred care approaches to address the needs of children with PI or PM and their families.