Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood psychiatric disorder. Research indicates that approximately one third of children with ADHD also have a chronic multiple tic disorder. Although ADHD symptoms are not significantly different in children with (+Tics) and without tics (-Tics), the presence of tics with ADHD indicates more severe co-occurring psychiatric symptoms and a risk for the development of other disorders. Prospective, longitudinal studies are the preferred tools used to correctly diagnose these disorders; to assess how symptoms of each disorder change over time in relation to each other; and to determine the impact of these disorders on a child’s future psychopathology and ability to function both socially and academically. However, with the exception of our ongoing investigation, there are no published studies of symptom assessment at regular intervals of children with chronic tic disorder, with or without ADHD. This study is an extension of an ongoing, NIMHfunded program initially designed to investigate short- and long-term safety and efficacy of Ritalin therapy for ADHD in children with ADHD/+Tics. We will evaluate the long-term implications of ADHD treatment in children with ADHD and chronic tic disorder, differences between ADHD children with (ADHD/+Tics) and without a tic disorder (ADHD/-Tics), and developmental changes of symptoms. This project will also enable us to follow our preadolescent sample into adolescence, conducting follow-up assessments every 12 months for an additional two years. We anticipate that the elucidation of the clinical course and outcomes of children with ADHD/±Tics will aid in the development of targeted interventions to improve functioning of both patient groups, but especially those with ADHD/+Tics. Kenneth Gadow, Ph.D., Carla DeVincent, Ph.D., State University of New York, Stony Brook, New York Award: $44 ,602 Tourette Association of America Inc. – Research Grant Award 2005-2006