Longitudinal Study of Brain Development

The ABCD Study^® is a longitudinal study of brain development and child health. The study design and recruitment strategy have previously been described [34 (link)], but in brief, the study used school-based recruitment to enrol 11,875 children from 21 metropolitan sites across the USA. Children were aged between 9 and 10 years at time of enrolment, and they and their caregiver completed the baseline visit between 1 October 2016 and 31 October 2018, which consisted of questionnaires, clinical interviews, neurocognitive interviews, and a neuroimaging protocol. Exclusionary diagnoses include a current diagnosis of schizophrenia, a moderate/severe autism diagnosis, intellectual disability, or alcohol/substance use disorder.
Our study received approval from the institutional review board of the University of Southern California. The ABCD Study obtained centralised institutional review board approval from the University of California, San Diego, and each of the 21 study sites obtained local institutional review board approval. Ethical regulations were followed during data collection and analysis. Parents or caregivers provided written informed consent, and children gave written assent. Data can be accessed through registration with the ABCD study at https://nda.nih.gov/abcd. The present analyses used data from the baseline (demographic information, co-occurring psychopathology) and follow-up phase one visits (SRS). A total of 11,878 children were recruited at baseline, and of these, 11,736 participated in sMRI scanning. As the ABCD cohort contains data from siblings, measures from a random sample of 7875 unrelated individuals were used, of which 345 were excluded due to poor quality sMRI data. Of the remaining 7521 participants, 7005 had available data on autistic traits, and thus made up the present sample. During the screening process, caregivers were asked if their child had previously received a diagnosis of a mental health condition. In the present sample, a total of 107 (1.53%) children were reported to have an autism diagnosis, and 1053 (15.03%) were reported to have a diagnosis of another mental condition including ADHD, depression, bipolar disorder, anxiety, or a specific phobia.