Consort diagram for study. Individuals could have multiple reasons for exclusion at each step. Other* accounts for individuals not contacted by staff in error or to avoid cohort imbalance. Screen failures were due to disclosure of exclusionary factors during the study visit (e.g., during semi-structured interviews). Neurodev. = neurodevelopment, neuroend. = neuroendocrine, mod. or sev. TBI = moderate or severe traumatic brain injury, Cn. <6 m; incom. Rec. = concussion within the last 6 months or incomplete recovery from prior concussion. Alc./subs. = alcohol/substance use, <12 m = less than 12 months.