Aripiprazole in children with Tourette's disorder and co-morbid attention-deficit/hyperactivity disorder: a 12-week, open-label, preliminary study

Tourette's disorder (TD) in children and adolescents is frequently co-morbid with attention-deficit/hyperactivity disorder (ADHD). Dopamine-blockers are the first line treatment for TD, whereas dopamine-agonists, such as stimulants, are the gold-standard in the treatment of ADHD. These contrasting effects supported concerns about the risk that stimulants for treating ADHD may trigger or worsen co-morbid tics. Aripiprazole, a partial dopamine agonist, acts as an antagonist at dopamine D2 receptors in hyperdopaminergic conditions and displays agonist properties under hypodopaminergic conditions. The present study describes the use of aripiprazole (10.0 ± 4.8 mg/day) in a consecutive group of 28 patients with a primary diagnosis of TD and co-morbid ADHD, combined subtype. The Yale Global Tic Severity Scale (YGTSS) and the ADHD-Rating Scale (ADHD-RS-IV) were used as primary outcome measures and both significantly improved (p<0.001) after the treatment. Global measures of severity (Clinical Global Impressions-Severity) and of functional impairment (Children's Global Assessment Scale) also significantly improved during the treatment (p<0.001). At the YGTSS there was a reduction of 42.5%, in motor tics, of 47.9% in phonic tics (44.7% for the combined scores), and of 32.3% in tic impairment. Nineteen patients (67.9%) had a reduction of at least 50% of the YGTSS score (motor+phonic tics). The improvement at the ADHD-RS-IV score was 22.5%, 12 patients (42.8%) presented an improvement of 30%, but only 2 (7.1%) an improvement greater than 50%. Using a logistic regression model, a reduction of at least 30% in ADHD-RS-IV score was more likely to occur in the obsessive-compulsive disorder co-morbid group. Aripiprazole was well tolerated and none of the patients discontinued medication because of side effects. In summary, aripiprazole resulted in an effective treatment for TD, but it was only moderately effective on co-occurring ADHD symptomatology. Our preliminary data suggest that aripiprazole may represent a possible therapeutic option, among other possible monotherapies addressing both tics and ADHD.