Recruiting to an EU-funded observational study investigating the long-term adverse effects of methylphenidate on children and adolescents with ADHD (ADDUCE) in 5 European countries

Introduction and objectives Methylphenidate is the most frequently used medication for the treatment of ADHD in Europe and yet information about its longterm safety is scarce. Recognising the need for further information the EU issued an FP7 call in 2009 and the ADDUCE study was designed in response. Its aim is to study the adverse effects of methylphenidate on children with ADHD living in Europe. Methods 800 children with ADHD beginning methylphenidate treatment, 400 unmedicated children with ADHD and 400 children without ADHD are being recruited and their neurological, psychiatric and physical health assessed every 6 months for 2 years at sites in the UK (6 sites), Germany/Switzerland (14 sites), Italy (6 sites) and Hungary (1 site). Results We have recruited 561 children with ADHD + methylphenidate, 304 children with ADHD and 151 children without ADHD totalling 1016. The projections indicate we will reach our recruitment targets for the ADHD groups by August 2014, when recruitment will end. The non-ADHD control group may not reach its target. Retention is currently around 75%, which is as predicted and accounted for in the recruitment targets. Data are being entered at each site using an online interface which researchers access via their own password-protected user accounts. Around 30% of data collected thus far have been entered into the database. Data are being monitored and cleaned as the study progresses. Discussion The study is on track to provide valuable new information about the adverse effects of methylphenidate treatment for ADHD in children and adolescents.