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Attention deficit hyperactivity disorder (ADHD) is a mental disorder of the neurodevelopmental type. It is characterized by problems paying attention, excessive activity, or difficulty controlling behavior which is not appropriate for a person's age.

A child with ADHD hyperactive-impulsive type has most or all of the following symptoms, excluding situations where these symptoms are better explained by another psychiatric or medical condition:

Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences
Have difficulty waiting for things they want or waiting their turns in games,
Often interrupt conversations or others' activities.

Overall, studies have shown that people with ADHD tend to have higher scores on intelligence quotient (IQ) tests found on the internet, but lower than median scores on professionally administered tests.