ATTENTION DEFICIT DISORDER
Definition
The term "attention deficit" is misleading. In general, the current predominating theories suggest that persons with ADHD actually have difficulty regulating their attention; inhibiting their attention to nonrelevant stimuli, and/or focussing too intensely on specific stimuli to the exclusion of what is relevant. In one sense, rather than too little attention, many persons with ADHD pay too much attention to too many things, leading them to have little focus. The major neurologic functions disturbed by the neurotransmitter imbalance of ADHD fall into the category of executive function. The 6 major tasks of executive function that are most commonly distorted with ADHD are (1) shifting from one mindset or strategy to another (i.e., flexibility), (2) organization (e.g., anticipating both needs and problems), (3) planning (e.g., goal setting), (4) working memory (i.e., receiving, storing, then retrieving information within short-term memory), (5) separating affect from cognition (i.e., detaching one's emotions from one's reason), and (6) inhibiting and regulating verbal and motoric action (e.g., jumping to conclusions too quickly, difficulty waiting in line in an appropriate fashion).
Like most complex neurobehavioral syndromes, the aetiology of ADHD is unknown (Daruna et al. 2000). Genetic factors as well as other factors affecting brain development during prenatal and postnatal life are most likely involved (Daruna et al. 2000). The use of functional neuro-imaging has led to identification of a number of consistent features in the brains of ADHD children. These features include decreased arousal and glucose metabolism and increased theta (4 to 8 Hz) activity in both the frontal and subcortical regions (Thompson and Thompson 1998). Results of animal studies and the therapeutic success of psychostimulant medication suggest that the aetiopathology of ADHD may involve hypofunctional dopamine pathways and other neurotransmitter imbalances (Kidd 2000).
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Heredity: children with ADHD usually have at least one first-degree relative who also has ADHD and one-third of all fathers who had ADHD in their youth have children with ADHD (National Institute of Mental Health 2001).
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Gender: ADHD is more prevalent in boys; the male-to-female ratio is 4:1 in epidemiologic surveys and 9:1 in clinic samples (Daruna et al. 2000).
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Prenatal and early postnatal health: maternal drug, alcohol, and cigarette use (National Institute of Mental Health 2001); in-utero exposure to toxins, including lead, dioxins and polychlorinated biphenyls (PCBs); nutrient deficiencies and imbalances.
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Abnormal thyroid responsiveness (possibly caused by exposure to pollutants during perinatal period) (Kidd 2000).
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Learning disabilities, communication disorders (Kidd 2000), and tic disorders such as Tourette's syndrome (American Psychiatric Association 1994).
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Nutritional factors: allergies or intolerances to food, food colouring, or additives (Kidd 2000).
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Environmental exposures: chronic exposure to lead and other toxic metals have been linked to a variety of neurobehavioral sequelae in children (Kidd 2000).
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Extreme or pervasive psychosocial stressors (such as marital discord or parental psychopathology); in isolation probably not a major cause of ADHD, but may contribute in combination with other risks (Wolraich and Baumgaertel 1997).
Symptoms & Signs - Inactive
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Fails to give close attention to details or makes careless mistakes
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Has difficulty sustaining attention in tasks or play activities
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Does not seem to listen when spoken to directly
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Does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace
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Has difficulty organizing tasks and activities
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Avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort
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Loses things necessary for tasks or activities
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Is easily distracted by extraneous stimuli
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Is forgetful in daily activities
Symptoms & Signs - Hyperactive
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Fidgets with hands or feet, or squirms in seat
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Leaves seat in situations where remaining seated is expected
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Runs or climbs excessively in inappropriate situations (in adolescents or adults, may be limited to subjective feelings of restlessness)
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Has difficulty playing or engaging in leisure activities quietly
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Acts as if "driven by a motor"
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Talks excessively
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Blurts out answers before questions are completed
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Has difficulty awaiting turn
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Interrupts or intrudes on others