2.3. Procedures
At baseline, 626 children with at least one first-degree relative who was reported to have experienced mania problems were classified into the at-risk group. This at-risk group was matched by sex and age to a control group with no first-degree relatives with mania problems. Within the at-risk group, participants were further divided into trauma and no-trauma subgroups based on whether they had experienced at least one of the nine interpersonal traumatic events according to the KSADS PTSD measure (Figure 1). Consequently, 198 children were classified in the trauma subgroup and 438 in the no-trauma subgroup. Due to missing data, only 555 children from the at-risk group were included in the two-year follow-up. At two-year follow-up, children who endorsed at least one interpersonal traumatic event either at baseline or at the follow-up were classified into the trauma subgroup, leading to 205 children in the trauma subgroup and 350 in the no-trauma subgroup at follow-up. The different traumatic events experienced by the children at baseline and follow-up are shown in Figure 1 .
The KSADS-PL was used to assess whether participants experienced manic, depressive, and/or anxious symptoms. Anxiety disorders of interest were social anxiety disorder (SAD) and generalized anxiety disorder (GAD) because all others (panic disorder (PD), agoraphobia, and separation anxiety disorder) were not endorsed. The ABCD dataset included a summary score of the different psychopathologies’ symptoms with a Boolean scoring method. Scores were divided into ”past” and ”present” timepoints indicating the time at which the KSADS-PL was administered within the ABCD study. This study only included the “present” timepoint.