Author Identifiers

Wendy Simpson

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


School of Arts and Humanities

First Advisor

Trudi Cooper

Second Advisor

Vicki Banham


A growing amount of research focuses on siblings of children with disabilities. However, limited evidence exists to provide a solid understanding and depth of knowledge of the issues that affect adult sibling relationships when one has intellectual disability. Since sibling relationships are the longest lasting family relationship, they are becoming more important because people with disability are outliving their parents or main caregivers. The increased longevity of people with disability has a societal and economic impact that has been recognised in the context of the recently introduced National Disability Insurance Scheme (NDIS) in Australia. By exploring the experiences of siblings who have a brother or sister with intellectual disability, this study aimed to understand how family characteristics and childhood experiences influence sibling relationships and decision-making across the life span.

Utilising a mixed methods approach—predominantly a qualitative study design—a total of 79 adult siblings of a person with intellectual disability from Perth, Western Australia, completed an online survey and/or participated in an interview. Participants ranged in age from 18 to 70+ years of age. Qualitative data were analysed using a thematic analysis process, guided by Braun and Clarke’s (2006) six-phase framework. Four major themes were constructed that captured the experience of growing up with a sibling with intellectual disability: relationships, knowledge and understanding of disability while growing up, siblings as carers and the consequences for family.

The findings revealed that the birth or diagnosis of a child in the family with intellectual disability resulted in a change in the family dynamics, a focus on the child with disability and parental differential treatment. Siblings reported a sense of having missed out while growing up and an ascribed or assumed role of carer. The variables that influence the relationship between siblings when one has intellectual disability were found to be broad, including individual, family and disability characteristics. In addition, this study found evidence to support findings from earlier research that correlates growing up with a sibling with disability and a propensity to follow a career path in a helping or service profession. Limited evidence was found in this study of a mutually beneficial close relationship with a sibling with intellectual disability that did not have elements of care, protection or a sense of responsibility attached. Findings also revealed that in adulthood, siblings often felt ‘disconnected’ from their sibling with intellectual disability when formal support services were in place, sometimes leading to discord between service providers and siblings regarding the nature of support for their sibling with intellectual disability.

These findings have implications for policy and practice in disability services because they highlight the importance of holistic family inclusion that includes siblings to enhance natural relationships and supported decision-making with siblings with intellectual disability. Recommendations include the recognition of siblings in policy and legislation, particularly in the NDIS; the inclusion by disability support and early intervention services of siblings in family discussions, planning and decision-making; and making readily available augmentative and alternative methods of communication as an imperative means of promoting sibling connectedness when one has intellectual disability. This study adds to the literature on adult sibling-disability research from an Australian perspective.