Mean Scores (± SD) and Reliability Estimates for Each Task in the Study.

The reliability of In-scanner head motion was Spearman-Brown-corrected split-half reliability, and that of BIS Impulsivity was Cronbach's alpha for items in the questionnaire. Note that the reliabilities of the components of impulsivity (e.g., self-control) were medium, possibly because the number of items for each component was small (e.g., 6 items for self-control). ADHD: attention deficit hyperactivity disorder; TDC: typically-developing controls; BIS: Barratt impulsiveness scale.