Abstract
BACKGROUND: Patients with attention deficit/hyperactivity disorder (ADHD) often experience comorbid conditions, such as autism spectrum disorder (ASD) and Tourette syndrome (TS). Although pharmacotherapies are effective for treating ADHD, they are likely to elicit a variety of adverse effects. It is, thus, important to select an effective and well-tolerated pharmacotherapeutic treatment for patients with ADHD/ASD comorbid with TS. CASE PRESENTATION: We report the case of a 10-year-old boy with ADHD/ASD comorbid with TS who was treated with guanfacine (GUAN). He experienced several side effects of atomoxetine (ATX) and methylphenidate (MPH) before being treated with GUAN. In the presented case, symptoms of ADHD as well as tic symptoms were improved by treatment with GUAN. CONCLUSION: GUAN might be effective and well tolerated in the treatment of patients with ADHD/ASD comorbid with TS who experience side effects of ATX and MPH.