Do different types of ADHD exist?

Yes. The DSM-IV-TR identifies three subtypes of ADHD (Table 1). Some children have symptoms that suggest a mainly hyperactive–impulsive type. To meet criteria for this subtype, a child must exhibit six or more symptoms (including restlessness, frequent interrupting, or talking excessively; see Table 2 for the list of core symptoms). The second subtype emphasizes inattention. To have a diagnosis of this subtype of ADHD, a child must have difficulty following directions, fail to pay close attention to details, be forgetful in daily activities, or become easily distracted. In the third subtype, the combined type, a child must display six or more symptoms of both inattention and of hyperactivity–impulsivity.