Purpose: This exploratory study examines psychosocial functioning of siblings of children with anxiety disorders. The lack of research in this area is surprising because anxiety disorders are the most common mental health problem for children (Verhulst et al., 1997) and tend to run in families (Skre et al., 1994).

Methods: Parents with children in treatment for anxiety disorders were asked to complete the Child Behavioral Checklist for Children/Ages 6-18 (CBCL/6-18; Achenbach & Rescorla, 2001) on the children's siblings. Parents also provided demographic, personal history (e.g., mental health diagnoses), and family functioning information. The outcomes were internalizing, externalizing, and total CBCL/6-18 scores.

Results: Data were collected on 65 siblings; 8 (12%) of the siblings had clinical mental health diagnoses. Of the 57 siblings who did not have a diagnosis, 31 (54%) had scores in the borderline or clinical range on the CBCL/6-18. A greater proportion of the siblings had elevated scores as compared to a non-referred sample (z = 13.8, p < 0.05). Almost half (n = 30, 46%) of the parents reported a history of an anxiety disorder, depression, or both. Regression analyses were used to examine psychosocial functioning in the sibling, with parental history of a psychiatric diagnosis, characteristics of the anxious child (having only an anxiety disorder v. having both anxiety and depression; length of treatment), and interference in family functioning used as predictors. None of the predictors were significant for externalizing behaviors (F = 1.29, p = .284). A parent having a psychiatric diagnosis and degree of family interference were significant for predicting internalizing behaviors (F = 3.51, p = .012, R2 = .19). Parental psychiatric diagnosis, degree of family interference, and length of anxious child's treatment were predictive of the total score (F = 3.231, p = .018, R2 = .18).

Implications: There were many siblings with borderline or elevated scores who were not identified indicating the need for greater screening. Children who have siblings with anxiety disorders – especially if there is greater family interference due to the anxiety disorder – and those with parents with a history of psychiatric diagnosis are at greater risk for having poorer psychosocial functioning. Therefore, clinicians treating children with anxiety disorders should ask screening questions about siblings' and parents' current functioning and psychiatric history. These findings reiterate the importance of evaluating children and their family context, and providing treatment to other family members as needed.

Achenbach, T., & Rescorla, L. ( 2001). Manual for the ASEBA school-age forms & profiles. Burlington, VT: University of Vermont, Research Center for Children, Youth, & Families. Skre, I., et al. (1994). A family study of anxiety disorders: Familial transmission and relationship to mood disorder and psychoactive substance use disorder. Acta Psychiatrica Scandinavica, 90, 366-374. Verhulst, F., et al. (1997). The prevalence of DSM-III-R diagnoses in a national sample of Dutch adolescents. Archives of General Psychiatry, 54, 329-336.