Sociology Ph.D. Dissertations


The Association Between Sibling Type, Sibling Relationship Quality, and Mental Health from Adolescence into Young Adulthood

Date of Award


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)



First Advisor

Kei Nomaguchi (Advisor)

Second Advisor

Amy L. Morgan (Other)

Third Advisor

Karen Guzzo (Committee Member)

Fourth Advisor

I-Fen Lin (Committee Member)

Fifth Advisor

Wendy D. Manning (Committee Member)


The majority of Americans have siblings, who provide one another with warmth, support, and friendship, and also serve as a source of conflict, throughout the life course. Past research shows that sibling relationship quality influences mental health and self-concept. Over the past several decades, as more parents break up and re-partner, a substantial proportion of America’s youth grow up with half-siblings or step-siblings. Limited research has examined how sibling relationship quality with half-siblings or step-siblings differs from those with full-siblings, however.

Using Waves II and III of the National Longitudinal Study of Adolescent to Adult Health, drawing from the core sample (N = 8,402) and the residential sibling pairs sample (N = 1,753), this dissertation examines the following three questions : (1) Does residential sibling relationship quality in adolescence, measured as feelings of love, fights, and time spent together, vary across full-siblings, half-siblings, and step-siblings, controlling for variation by sibling type in family characteristics, such as mother-child relationship quality, father-child relationship quality, and family belonging? (2) Does sibling relationship quality in young adulthood, measured as visits, phone calls, help-seeking, fights, and emotional closeness, vary by sibling type, controlling for sibling relationship quality during adolescence? (3) Does the association between relationship quality with residential siblings in adolescence and mental health and self-concept in young adulthood differ across the three residential sibling types?

The findings suggest that among residential siblings, with the same family characteristics, relationships with step-siblings are more distant than those with full-siblings or half-siblings, while relationships with half-siblings are similar to those with full-siblings, both in adolescence and young adulthood. Emotionally close relationships and fights with siblings in adolescence are associated with better self-esteem and fewer depressive symptoms in young adulthood, with variation by sibling type in ways that are more complex than predicted based on the “stepfamily as incomplete institution” perspective. Fights indicate closer, rather than more distant, sibling relationships. Overall, the findings contribute to the existing bodies of family, sibling, and mental health research, suggesting the merit to further investigating differences in the nature of full-siblings, half-siblings, and step-siblings and their implications for individual well-being across different life stages.