The Attention Deficit Hyperactivity Disorder Drugs Use Chronic Effects (ADDUCE) study is an EU FP7 funded study designed to asses the longer term safety and tolerability of methylphenidate in the treatment of ADHD. ADDUCE combined systematic reviews, secondary data analysis and a detailed cross sectional investigation of cardiovascular functioning with a large prospective 2 year observational study to investigate the long term impacts of methylphenidate on growth and puberty, and the cardiovascular, psychiatric, neurological systems. The four talks in the symposium will present the main findings from ADDUCE and discuss their clinical relevance.