When Siblings have Intellectual and Developmental Disabilities

by Doreen Arcus

She would have been 100 this year. Perhaps the most influential person with intellectual and developmental disabilities in modern America, Rosemary Kennedy changed the lives of millions.

And she did it through her siblings.

Born at a time when families were advised to institutionalize children with disabilities, Rosemary was instead an integral part of Kennedy family life until a prefrontal lobotomy left her incapacitated at age 23. She was particularly close to her younger sister Eunice. She went to dances escorted by big brother Jack. And when she went away after the ill-advised lobotomy, her departure left 9-year-old Teddy, her youngest brother and adoring godson, confused and frightened.

She may have been out of sight, but definitely was not out of mind. Rosemary’s siblings did not forget her.

Instead, they became the force behind landmark legislation and policy changes that brought the treatment of people with intellectual and developmental disabilities (I/DD) from a Dickensian existence at the margins of society into the mainstream and the light of day.

Senator Edward Kennedy championed the Americans with Disabilities Act, sponsored legislation allowing low- and middle-income families of children with disabilities to obtain health insurance through Medicaid, and co-sponsored reauthorization of the Individuals with Disabilities Education Act.

President John Kennedy established the National Institutes of Child Health and Human Development, appointed a Presidential Panel on Mental Retardation, and established funding for research, community-based treatment, and teacher training.

Eunice Kennedy Shriver founded the Special Olympics, created prominent research centers for developmental disabilities, and was the force behind the scenes in JFK’s disability accomplishments.

But in considering these accomplishments, we often forget that there was a force behind the force: Rosemary. As the Senator recalled in his 2009 memoir, True Compass, “Rosemary enriched the humanity of all of us.”

Sibling relationships are powerful, complicated beasts for anyone, including those whose brothers or sisters have I/DD, for whom the relationship may hold special challenges, impacting their lives from earliest childhood through old age.

When siblings with I/DD require extraordinary attention, for example, even young children may try to avoid overtaxing finite family resources. They may conceal their own needs, hesitate to ask for help, and strive to become self-sufficient before they are ready, becoming what professionals call “parentified.”

School-age siblings enjoy playing with their brothers or sisters with I/DD and sympathize with their struggles. But they are also aware of difficulties and the importance of developing strategies to cope with them—valuing the respite of time alone, seeking support from other typically developing siblings, and taking comfort in meeting other families like theirs.

As adolescents, typically developing siblings tend to worry about those with I/DD. They may feel anxiety, depression, and even hostility, especially when the child with I/DD has behavior problems and when the demands of caring for that child are stressful and costly to the family. But as adolescents grow into adults, conflict tends to decrease and closeness to increase.

Although the challenges may be significant, there are rewards too.

Siblings of children with disabilities often develop compassionate, caring natures. They tend to be altruistic, to tolerate differences, to demonstrate more maturity than their peers, and to appreciate their own health and ability.

Elanna Seid was only four-years-old when her younger sister Rebecca was diagnosed with global developmental delays. Even at that early age, her parents found ways to help Elanna cope with the challenges that Rebecca’s disability presented to the family.

They enrolled her in a support program for siblings of young children with special health and developmental needs through The Arc of New Jersey. There, Elanna met other children from families like hers. She developed long-term supportive relationships, and learned to advocate for her sister and for others.

There were many opportunities for advocacy. Children with disabilities, for example, are bullied at rates significantly higher than their non-disabled peers. Elanna recalls seeing a group of older boys bullying a child with developmental disabilities on the school bus when she was just in the second grade. Empowered by her experiences in the sibling support program, Elanna confronted the boys about their unacceptable behavior.

Today she is a Speech-Language Pathologist specializing in Autism Spectrum Disorder, and serves on the Board of the Massachusetts Sibling Support Network. Elanna is like many adult siblings who enter “caring” professions, inspired by the struggles and triumphs they witnessed as children.

As people with I/DD grow into adulthood and their senior years, it is less likely to be parents at their side and more likely to be siblings—siblings who are also coping with their own work and family needs. When asked what supports would be helpful for this eventuality, these adult siblings were very clear.

They wanted information and support—to be connected to other siblings, be informed about financial and legal planning, be empowered to navigate “the system” with its waiting lists and red tape, and be effective in advocating for improved services and funding.

The impacts of I/DD are not limited to the child or adult who lives with the condition; they are shared to some extent by everyone who cares about that person. Support for siblings, families, and all who care can be found through organizations such as The Arc and its local chapters, The Sibling Support Project, the Sibling Leadership Network, and the Parent Center Hub of the US Department of Education, Office for Special Education Programs.

Rosemary Kennedy was tragically shut away from her adult siblings for decades. Today, thanks to many of the policies that those siblings helped establish, Rebecca Seid and millions of others are anything but.

Elanna is planning her wedding for next year. Not only will Rebecca be invited, she will be her sister’s maid of honor.



Doreen Arcus, Ph.D.- Associate Professor, Department of Psychology, University of Massachusetts Lowell



Rosemary Kennedy general information. Larson, K.C. (2015). Rosemary: The hidden Kennedy daughter. NY: Houghton-Mifflin.

Kennedy sibling accomplishments… https://www.jfklibrary.org

According to the Senator… Kennedy, E.M. (2009). True Compass. NY: Twelve. p. 25

When a child needs extraordinary attention… Lamorey, S. (1999). Parentification of siblings of children with disability or chronic disease. In N. D. Chase, N. D. Chase (Eds.), Burdened children: Theory, research, and treatment of parentification (pp. 75-91). Thousand Oaks, CA, US: Sage Publications, Inc. doi:10.4135/9781452220604.n4 https://books.google.com/books?id=xbYgIm2hjOEC&pg=PA75&lpg=PA75

School-aged siblings… Moyson, T., & Roeyers, H. (2012). ‘The overall quality of my life as a sibling is all right, but of course, it could always be better’. Quality of life of siblings of children with intellectual disability: The siblings’ perspectives. Journal of Intellectual Disability Research, 56(1), 87-101. doi:10.1111/j.1365-2788.2011.01393.x https://www.ncbi.nlm.nih.gov/pubmed/21366753

As adolescents, typically developing siblings worry… Shivers, C. M., & Dykens, E. M. (2017). Adolescent siblings of individuals with and without intellectual and developmental disabilities: Self-reported empathy and feelings about their brothers and sisters. American Journal on Intellectual and Developmental Disabilities, 122(1), 62-77. doi:10.1352/1944-7558-122.1.62 https://www.ncbi.nlm.nih.gov/pubmed/28095054

As adolescents grow into adults… Floyd, F. J., Costigan, C. L., & Richardson, S. S. (2016). Sibling relationships in adolescence and early adulthood with people who have intellectual disability. American Journal on Intellectual and Developmental Disabilities, 121(5), 383-397. doi:10.1352/1944-7558-121.5.383 https://www.ncbi.nlm.nih.gov/pubmed/27611350

Siblings of children with disabilities often… Dyke, P., Mulroy, S., & Leonard, H. (2009). Siblings of children with disabilities: Challenges and opportunities. Acta Paediatrica, 98(1), 23-24. doi:10.1111/j.1651-2227.2008.01168.x

Elanna Seid is a Speech-Language Pathologist in the Boston Public Schools. She has read this essay and confirmed the facts of her story.

The Arc of New Jersey. http://www.arcnj.org

Children with disabilities, for example, are bullied… https://www.stopbullying.gov/sites/default/files/2017-09/bullyingtipsheet.pdf

Massachusetts Sibling Support Network. http://www.masiblingsupport.org

When asked what supports… Arnold, C. K., Heller, T., & Kramer, J. (2012). Support needs of siblings of people with developmental disabilities. Intellectual and Developmental Disabilities, 50(5), 373-383. doi:10.1352/1934-9556-50.5.37 https://www.ncbi.nlm.nih.gov/pubmed/23025639

Supports for sibling, families, and all who care…

The Arc. http://www.thearc.org

The Sibling Support Project. https://www.siblingsupport.org

Sibling Leadership Network. http://siblingleadership.org

Parent Hub US DOE OSEP. http://www.parentcenterhub.org/repository/siblings