Children with the inattentive type may:
- Have short attention spans.
- Be distracted easily.
- Not pay attention to details.
- Make many mistakes.
- Fail to finish things.
- Have trouble remembering things.
- Not seem to listen.
- Not be able to stay organized.
Children with the hyperactive-impulsive type may:
- Fidget and squirm.
- Be unable to stay seated or play quietly.
- Run or climb too much or when they should not.
- Talk too much or when they should not.
- Blurt out answers before questions are completed.
- Have trouble taking turns.
- Interrupt others.
The most common type is combined attention-deficit/hyperactivity disorder, which, as the name implies, is a combination of the inattentive and the hyperactive-impulsive types.
A diagnosis of one of the attention-deficit/hyperactivity disorders is usually made when children have several of the above symptoms that begin before age 7 and last at least 6 months. Generally, symptoms have to be observed in at least two different settings, such as home and school, before a diagnosis is made.

