Stage I: Medical charts of these subjects will be reviewed to obtain information about CONCERTA adherence (also including dosage, treatment duration, clinic visits, missing visits etc.), psychiatric co-morbidities, and other treatment approaches subjects received after the previous study. Subjects will be visited (Visit 1) and the information of baseline characteristics and reasons for discontinuing CONCERTA (if applicable) will be recorded. The assessments will included parent or teacher ratings on the Conner's Teacher and Parent Rating scales (CPRS-R:S, CTRS-R:S), the SNAP-IV rating scale, the SKAMP rating scale, investigator ratings on the Kiddie-SADS-E, Clinical Global Impression and the Social Adjustment Inventory for Children and Adolescents (SAICA); and neuropsychological assessments (Conner's Continuous Performance Test, CPT, and Cambridge Neuropsychological Test Automated Batteries, CANTA B) will be performed to these subjects.