Children with ADHD may have trouble paying attention, controlling impulsive behaviors, or be overly active. Often, maintaining focus at school is very difficult, meaning that many children with ADHD may fail to achieve their potential, despite high intelligence. Children with ADHD may be considered naughty or rude by teachers, or simply overlooked in lessons.

There are three different types of ADHD, depending on which symptoms are most noticeable in the child.

• Predominantly Inattentive Presentation: It is hard for the individual to organize or finish a task, to pay attention to details, or to follow instructions or conversations. The person is easily distracted or forgets details of daily routines.

• Predominantly Hyperactive-Impulsive Presentation: The person fidgets and talks a lot. It is hard to sit still for long (e.g., for a meal or while doing homework). Smaller children may run, jump or climb constantly. The individual feels restless and has trouble with impulsivity. Someone who is impulsive may interrupt others a lot, grab things from people, or speak at inappropriate times. It is hard for the person to wait their turn or listen to directions. A person with impulsiveness may have more accidents and injuries than others.

• Combined Presentation: Symptoms of the above two types are equally present in the person.