The primary research objective of this observational study is to evaluate treatment compliance over one year in children and adolescents who are newly initiated on medication approved for the treatment of ADHD in a routine clinical setting. Compliance will be assessed using the Pediatric Compliance Self-Rating (PCSR) Instrument. A patient will be considered as compliant at a given visit, if the PCSR score is at least 5, corresponding to taking the medication at least often.