Methylphenidate (Ritalin©, MPH) is dopamine transporter (DAT) inhibitor used as a treatment of Attention-Deficit/Hyperactivity Disorder (ADHD), a highly prevalent, clinically heterogeneous neuropsychiatric disorder characterized by impairing levels of inattention and/or hyperactivity associated with impulsive behaviors1,2. Here, SLC6A3 is linked to attention deficit-hyperactivity disorder.