The ABCD protocol is a comprehensive set of physical, cognitive, social, emotional, environmental, behavioral, and academic assessments, as well as multimodal neuroimaging and biospecimen collection for hormonal, genetic, epigenetic, environmental exposure, and substance use analysis. These assessments are anticipated to be done annually (non-imaging) or biannually (imaging and bioassays) for 10 years. Participants also undergo a brief, mid-year phone interview. Click on the image, below, to view a timeline of events: