Attention deficit hyperactivity disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) is the most common childhood-onset behavioural disorder.

Those affected have a greatly reduced ability to maintain attention without being distracted, to control what they're doing or saying (because of impulsivity) and to control the amount of physical activity appropriate to the situation (that is, they're restless and fidgety).

ADHD is also called attention deficit disorder (ADD) or hyperactivity. The disorder shouldn't be confused with normal, boisterous childhood behaviour.