Purpose: It is commonly assumed that siblings of adults with severe mental illness will take on a caregiving role when their parents become disabled or die. Several studies examining these siblings indicate that the quality of the relationship that is shared between a sibling and his or her brother/sister with a severe mental illness is a major influence on the sibling's current or expected caregiving responsibilities. Yet little is known about the factors that sustain the bonds of affection between siblings when one sibling has schizophrenia. The purpose of this study was to begin to fill this gap in our knowledge by examining factors that promote or detract from the quality of the relationship between a sibling and his or her brother or sister with schizophrenia.

Methods. The data come from a large scale NIMH funded longitudinal study of aging mothers of adults with schizophrenia. Mothers were asked to identify the sibling who would most likely be involved in the care of their brother or sister with schizophrenia when the parents became disabled or died. Letters were sent to 192 siblings, and 145 (75.5%) agreed to participate. The sibling participants had a mean age of 44.0 years, about three-fourths were married, and half were college graduates.

Results: A multiple linear regression analysis examining the predictors of relationship quality between a sibling and a brother or sister with schizophrenia revealed that higher levels of family cohesion while growing up promoted a greater quality in their current relationship. The personal gain experienced by siblings from years of coping with their brother or sister's illness significantly predicted the quality of their relationship. The unpredictability of a brother or sister's behavior problems significantly predicted a lower quality in the sibling relationship. Siblings who viewed their brother or sister as having control over their symptoms and behaviors perceived a lower quality in the sibling relationship.

Implications: Understanding the quality of the sibling relationship can help shape services that work to strengthen family relationships by informing service providers about factors that promote or deteriorate the bonds of affection. Strengthening these bonds could have a positive impact on the sibling's current level of care provision, expectation for future involvement, or on the sibling's psychological well-being. In addition, improving the quality of the relationship might also promote the quality of life of the brother or sister with schizophrenia.