Risk and resilience factors impacting the mental health and wellbeing of siblings of individuals with neurodevelopmental conditions: A mixed methods systematic review

Objective: This pre-registered systematic review synthesised and evaluated the existing literature on self-reported mental health and wellbeing of siblings of individuals with neurodevelopmental conditions (NDCs). Methods: From 2437 identified studies published 2000–2022, 81 studies were included: 14 population- or cohort-based, 39 quantitative, 7 mixed method, and 21 qualitative outcome studies. Results: Seven sibling mental health (any psychiatric disorder, anxiety, depression, bipolar disorder, schizophrenia, internalising and externalising difficulties) and five wellbeing indicators were identified (quality of life, emotional adjustment, social wellbeing, somatic/physical wellbeing, and resilience/growth). Overall, siblings had increased risk of any psychiatric disorder, but they also reported experiences of growth and resilience, primarily in qualitative studies. 41 risk factors and 24 resilience factors associated with these outcomes were identified; the most frequently cited risk factor was symptom severity of the NDC sibling, while the most common resilience factor was adaptive/active coping at the individual sibling level. Studies showed high methodological heterogeneity and 90 different self-report measures were used. Conclusions: Sibling mental health indictors are heterogeneous and cumulative risk factors may result in poorer wellbeing. There is a need for consistent reporting of family and sibling characteristics, a strengths-based approach to assessment, and identification of protective and resilience-promoting factors.