2.1.2 Family History
The main inclusion criterion for this study’s at-risk group was for participants to have at least one first-degree relative with BD. Familial history was identified using the “ABCD Parent Family History Summary Scores” data. It includes a summary score of all that was reported by the caregiver on lifetime occurrences of different psychological issues in first- and second-degree biological relatives of the participants. Variables of interest were those that assessed whether “mania problems” were experienced by the father, mother, or siblings. In total, 625 participants were considered at-risk at baseline, and 545 were identified at the two-year follow-up. Adopted children were not uniformly excluded from the current study since these assessments specifically referred to biological first-degree relatives.