and its inclusion criteria to professional membership listservs of research organizations, including Division 53 of the American Psychological Association and the International Society for Research in Child and Adolescent Psychopathology, and to authors who have published longitudinal studies of children with and without ADHD to determine whether relevant data were available. These efforts yielded 4 unpublished study samples. Although these samples appeared in peer-reviewed publications, the published results were incompatible with the standards outlined in the inclusion criteria (eg, substance outcomes not presented in relation to stimulant treatment). Most reviewed studies were excluded because they were qualitative reviews, substance outcomes were analyzed dimensionally, and/or medication treatment designations did not precede the measurement of substance use. One study that met the inclusion criteria18 was excluded given author concerns about potential confounds of treatment type in the small sample (Brooke Molina, PhD, written communication, September 2011). Yet another study was excluded19 given that patients with and without ADHD were included in the frequencies provided for the non-stimulant-treated group. When multiple studies with the same substance outcome were derived from the same sample, the most recent publication was used (ie, the longest follow-up period from baseline).
