As the most well-known presentation of ADHD, this is often noticed in childhood as hyperactivity (with inappropriately high levels of movement such as running or climbing) and impulsive actions and often leads to trouble with authority and peers.
In adolescents and adults, as the brain matures, so too does the control level, and the hyperactivity reduces from high levels of movement to minor restlessness and fidgeting.The main characteristics include:
- an under-control of behaviour
- higher than usual activity (hyperactivity is a state of being unusually or abnormally active), and
- acting on impulses without controlling these by thinking before acting.
Also, inattentiveness and executive dysfunction are often present, though generally to a lesser extent.