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  • Print publication year: 2002
  • Online publication date: August 2016

29 - Attention deficit hyperactivity disorder: spectrum and mechanisms



Attention deficit hyperactivity disorder (ADHD) is among the most prevalent disorders (3 to 5% of school-age children) treated by physicians who manage children/adolescents, comprising as much as half of child psychiatric practice (Cantwell, 1996). Media attention has been inspired by the extension of the ADHD diagnosis to adults, acknowledgement of frequent comorbidity or antecedent status with respect to other conditions, and concern over the increase in stimulant prescriptions; it may appear that ADHD, or at least its importance, is a novelty. In truth, the essential description of the disorder has a 75-year-long history under a variety of names: ‘incorrigibles’, ‘brain damaged’, ‘hyperkinetic’, and ‘Minimal Brain Dysfunction’ (Barkley, 1990). Since 1980, the term ‘attention’ has been the initial and therefore most prominent feature of the names given to the syndrome, either ‘attention deficit’ alone or combined with ‘hyperactivity’ (and ‘impulsivity’) comprising the other central features defining the clinical category (American Psychiatric Association Diagnostic and Statistical Manual, 1994). The current Diagnostic and Statistical Manual (DSM–IV) lists three subtypes: a combined or full ADHD; a predominantly inattentive; and a predominantly hyperactive/impulsive subtype (American Psychiatric Association Diagnostic and Statistical Manual, 1994). Experts suspect that the predominantly hyperactive/ impulsive subtype is most often seen in preschool children; there is more controversy about the predominantly inattentive subtype (except when it is only a residual form of the full syndrome, occurring in the adolescent and adult portions of the lifespan); controversial is whether those who present as children with the predominantly inattentive type have a disorder that is quite different. The heterogeneity of ADHD is one of the commonly documented but difficult characteristics of the disorder.


Hyperactivity may be the first sign to be noticed, obvious in nursery school when not much sustained attention or independent self-control is expected. A small percentage of children diagnosed with ADHD are retrospectively described as difficult right from the moment of birth and as children who ‘run rather than walk’ as soon as they get up on their feet. Most children with the ADHD diagnosis are also impulsive, which can be in terms of ‘on the mind, out the mouth’ and is not necessarily gross physical activity or aggressivity.