"Attention Deficit Hyperactivity Disorder (ADHD) is not one symptom or even two symptoms as the name might suggest. ADHD is not just deficient attention or excessive activity; it is a cluster of behaviours that are, more often than not, seen together. Thus, ADHD is a syndrome comprising of several, presumably connected, symptoms. When we use the phrase symptoms, we are generally referring to a set of behaviours. Many of those behaviours are extremes of behaviour seen in everyone, thus ADHD might be seen as existing along a continuum or a spectrum. The main behaviours observed in an individual with ADHD are impulsivity, inattention and hyperactivity. These three are the key characteristics of ADHD, but as we shall see when we look at diagnosis (see Chapter 2), this triad of behaviours is not always the absolute defining characteristic of ADHD. For example, ADHD can occur without the hyperactivity being present - so children do not have to be running around and bouncing off of the walls all the time in order to have ADHD. Or ADHD can be primarily about impulsivity, which the title ADHD does not allude to. Impulsivity may be the most impactful of behaviours seen in ADHD (see Chapter 4). Furthermore, for many they consider ADHD has been seen exclusively as a childhood disorder - a disorder that the child may eventually grow out of over time. However, over the past 30 years, research and clinical experience has been able to challenge this assumption by defining and identifying ADHD in adults."-- Provided by publisher.