Although the relationship between Tourette’s disorder (TD) and comorbid psychiatric disorders has been difficult to untangle, behavioral and emotional problems are typically the primary source of dysfunction and disability in clinically referred youth. Aggressive symptoms, such as explosive outbursts, have been described in as many of 25-70% of youth with TD. To date, the only formally approved treatments for TD are haloperidol and pimozide; both of which are typical neuroleptic agents known to have significant and unwanted side effects. Preliminary evidence suggests that aripiprazole is well tolerated and can reduce aggression in youth with conduct disorder. The current study will evaluate the efficacy and safety of aripiprazole in reducing explosive outbursts in youth with TD. Ours is a six-week, double blind, randomized, placebo controlled, parallel group clinical trial with a flexible dose titration design that will be carried out at two sites associated with the New York University School of Medicine. We are recruiting children between the ages of 6 and 17 with both TD and clinically impairing explosive outbursts that have not been responsive to other treatments. Thirty patients who meet eligibility criteria will be randomly assigned to receive either aripiprazole or placebo. Initial dose will be determined by body weight, and dose will be flexibly titrated upward based on clinical response. Clinical ratings, completed at baseline and weeks 1,2,3, 4, and 6 after study initiation include: the Yale Global Tic Severity Scale, the Repetitive Anger Outbursts Ratings, and the Children’s Aggression Scale-Parent Version. We hypothesize that aripiprazole will be more effective than placebo in reducing both the severity of explosive outbursts as well as tics in children and adolescents with TD and explosive outbursts Barbara Coffey, M.D. M.S., New York University Child Study Center, New York, New York Cathy Budman, M.D. North Shore University Hospital, Manhasset, New York Award: $75,000 Tourette Association of America Inc. – Research Grant Award 2005-2006