Personality Disorder). Mothers reported on the presence of conduct disorder and substance use disorder symptoms in her twin children through interviews using the parent version of the Diagnostic Interview for Children and Adolescents (Reich, 2000). A symptom was considered present if reported by either the mother or twin. Symptoms were assigned on the basis of a consensus, “best-estimate” approach (Leckman, Scholomskas, Thompson, Belanger, & Weisman, 1982) combining mother and twin interview data.
