eMedicine Specialties > Pediatrics: Developmental and Behavioral > Medical Topics

Attention Deficit Hyperactivity Disorder

Author: Susan Louisa Montauk, MD, Medical Director, The Affinity Center, Cincinnati; Professor, Departments of Family Medicine and Public Health Science, University of Cincinnati College of Medicine
Coauthor(s): Christine A Mayhall, PhD, Clinical Psychologist, The Affinity Center
Contributor Information and Disclosures

Updated: Feb 27, 2009

Introduction

Background

The term attention deficit is misleading. In general, the current predominating theories suggest that persons with attention deficit hyperactivity disorder (ADHD), attention deficit disorder (ADD), actually have difficulty regulating their attention; inhibiting their attention to nonrelevant stimuli, and/or focusing too intensely on specific stimuli to the exclusion of what is relevant. In one sense, rather than too little attention, many persons with ADHD (ADD) pay too much attention to too many things, leading them to have little focus.

Three basic forms of ADHD (ADD) are described in the Diagnostic and Statistical Manual IV (DSM-IV) of the American Psychiatric Association (APA).1 They are (1) attentional; (2) hyperactive/impulsive; and (3) combined, which is most frequently a combination of attentional and hyperactive forms.

The major neurologic functions disturbed by the neurotransmitter imbalance of ADHD (ADD) fall into the category of executive function. The 6 major tasks of executive function that are most commonly distorted with ADHD (ADD) include (1) shifting from one mindset or strategy to another (ie, flexibility), (2) organization (eg, anticipating both needs and problems), (3) planning (eg, goal setting), (4) working memory (ie, receiving, storing, then retrieving information within short-term memory), (5) separating affect from cognition (ie, detaching one's emotions from one's reason), and (6) inhibiting and regulating verbal and motoric action (eg, jumping to conclusions too quickly, difficulty waiting in line in an appropriate fashion).

Contrary to some media accounts, ADHD (ADD) is not new. In the early 1900s, diagnosis emphasized the hyperactivity component. Today, hyperactivity, impulsivity, and inattention are the areas of focus. However, reports have alluded to disorders involving hyperactivity, impulsivity, and inattention in conjunction with distractibility and inappropriate arousal patterns throughout medical history. What is new is the enhanced awareness of ADHD (ADD) secondary to rapidly accumulating research findings and its addition to the DSM in 1980.

Pathophysiology

Findings from neuropsychological studies suggest that the frontal cortex and the circuits linking them to the basal ganglia are critical for executive function and, therefore, to attention and exercising inhibition. Many findings support this view, including those described below.

Executive functions are major tasks of the frontal lobes. MRI of the right mesial prefrontal cortex in persons with ADHD (ADD) strongly supports decreased activation (low arousal) during tasks that require inhibition of a planned motor response and timing of a motor response to a sensory cue. MRI in persons with ADHD (ADD) also strongly supports weakened activity in the right inferior prefrontal cortex and left caudate during a task that involves timing of a motor response to a sensory cue.

The catecholamines are the main neurotransmitters with frontal-lobe function. Catecholamine controlled dopaminergic and noradrenergic neurotransmission appear to be the main targets for medications used to treat ADHD (ADD).

A 10-year study by National Institute of Mental Health (NIMH) demonstrated that the brains of children and adolescents with ADHD (ADD) are 3-4% smaller than those of children without the disorder, and that pharmacologic treatment is not the cause. The more severe patients' ADHD (ADD) symptoms were, as rated by parents and clinicians, the smaller their frontal lobes, temporal gray matter, caudate nucleus, and cerebellum were.

In addition to the role of the neurotransmitters most commonly associated with the frontal lobes and the pathways mentioned above, some investigations have begun exploring a possible role for 5-hydroxytryptamine (5-HT). Although the brain’s motor regions are innervated by 5-HT projections, no connection between 5-HT and ADHD (ADD) motor pathology has yet been identified. However, connections have been made to attention-related processes. Altered 5-HT activity does appear to be at least part of the cause for difficulties with perceptual sensitivity and the appropriate recognition of the relative significance of stimulation.

Frequency

United States

The prevalence of ADHD (ADD) in children appears to be 3-7%. ADHD (ADD) is associated with significant psychiatric comorbidity. Approximately 50-60% of individuals with this disorder meet DSM-IV criteria for at least one of the possible coexisting conditions, which include learning disorders, restless legs syndrome, ophthalmic convergence insufficiency, depression, anxiety disorders, antisocial personality disorder, substance abuse disorder, and conduct disorder. The likelihood of a person having ADHD (ADD) if a family member has ADHD (ADD) or one of the disorders commonly associated with ADHD (ADD) is significant.

International

People with ADHD (ADD) have been identified in every country studied, with comparable frequency.

Mortality/Morbidity

The morbidity for ADHD (ADD) widely varies. This range is a function of many factors, including the specific area of deficit, the patient's environmental response to and interaction with the deficits, the therapy provided, and the presence of coexistent conditions.

Sex

ADHD (ADD) is more frequently diagnosed in boys than in girls. Most estimates of the male-to-female ratio range between 3:1 and 4:1 in clinic populations. However, many community-based samples produce a ratio of 2:1. Recognition of ADHD (ADD) has improved over the last decade, and the male-to-female ratio has been decreasing; this may be the result of the increased recognition of inattentive ADHD (ADD).

Age

Data concerning the likelihood that a child with ADHD (ADD) will also have the disorder as an adult are conflicting. As definitions of ADHD (ADD) subtypes improve, some subtypes that cause more adult dysfunction than others will likely be found.

  • Approximately 30-80% of children with ADHD (ADD) have the disorder as adults. Most experts believe that the rate is well above 50%.
  • Hyperactive symptoms may decrease with age because of developmental trends toward self-control and changes in brain composition (ie, pruning of abundant neural connections) that occur during late adolescence. However, persons with ADHD (ADD) developmentally mature later than the average population. Inattentive symptoms do not appear to have a similar developmental advantage and tend to remain constant into adulthood.

Clinical

History

The DSM-IV criteria, in conjunction with a thorough clinical interview regarding daily functioning, are important in the diagnosis of attention deficit hyperactivity disorder (ADHD), previously termed attention deficit disorder (ADD). Of note, some of the DSM-IV criteria have been revised to reflect state-of-the-art knowledge, including data regarding ADHD (ADD) in girls and women. The clinician should also gather information that helps to identify any coexisting conditions. 

  • History of present illness: All of the following DSM-IV criteria for ADHD (ADD) must be present:
    • Either the criteria for inattention or the criteria for hyperactivity/impulsivity must be met.
      • Inattention: At least 6 of the 9 symptoms of inattention listed below must have persisted for at least 6 months to a degree that is maladaptive and inconsistent with the patient's developmental level.
        1. Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities
        2. Often has difficulty sustaining attention in tasks or play activities
        3. Often does not seem to listen when spoken to directly
        4. Often does not follow through with instructions and often fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions)
        5. Often has difficulty organizing tasks and activities
        6. Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (eg, schoolwork, homework); often loses things necessary for tasks or activities (eg, school assignments, pencils, books, tools, toys)
        7. Often is easily distracted by extraneous stimuli (eg, toys, school assignments, pencils, books, tools)
        8. Often is forgetful in daily activities
      • Hyperactivity/impulsivity: At least 6 of the 9 symptoms of hyperactivity (symptoms 1-6) and impulsivity (symptoms 7-9) listed below have persisted for at least 6 months to a degree that is maladaptive and inconsistent with the patient's developmental level.
        1. Often fidgets with hands or feet or squirms in seat
        2. Often leaves seat in classroom or in other situations in which remaining seated is expected
        3. Often runs about or climbs excessively in situations in which it is inappropriate (in adolescents and adults, may be limited to subjective feelings of restlessness)
        4. Often has difficulty quietly playing or engaging in leisure activities
        5. Often on the go or often acts as if driven by a motor
        6. Often talks excessively
        7. Often blurts out answers before questions have been completed
        8. Often has difficulty awaiting turn
        9. Often interrupts or intrudes on others (eg, butts into conversations or games)
    • Some hyperactive-impulsive or inattentive symptoms that caused impairment are present before age 7 years
    • Symptoms must be present in 2 or more situations (eg, school, work, home).
    • The disturbance causes clinically significant distress or impairment in social, academic, or occupational function.
    • Behavior does not exclusively occur during the course of pervasive developmental disorder, premenstrual dysphoric disorder, schizophrenia, or other psychotic disorder. No mood disorder, anxiety dissociative disorder, or personality disorder accounts for the behavior.
  • Past medical history
    • Screen for the following medications or supplements that may have negative interactions with ADHD (ADD)-related medications:
      • Anticonvulsant agents
      • Antihypertensive agents
      • Caffeine-containing drugs
      • Pseudoephedrine
      • Ephedra
      • Monoamine oxidase inhibitors (MAOIs)
      • All medications known to be metabolized by means of the cytochrome P450 (CYP) 2D6 hepatic pathway (See the discussion about atomoxetine in the Medication section.)
    • Screening for medical concerns that may have negative interactions with ADHD (ADD) medications (Drugs of concern are shown in parentheses.)
      • Major arterial disease (stimulants)
      • Narrow-angle glaucoma (stimulants, imipramine, desipramine)
      • Heart disease (clonidine, desipramine, guanfacine, imipramine, stimulants)
      • Heart palpitations (stimulants)
      • Hepatic disease (atomoxetine)
      • Hypertension (stimulants, atomoxetine, bupropion)
      • Orthostasis (atomoxetine, bupropion, stimulants)
      • Pregnancy (all)
      • Renal disease (bupropion, clonidine)
      • Seizure disorder (bupropion, desipramine, imipramine)
      • Urinary retention or hesitancy (atomoxetine, bupropion, stimulants)
    • Approximately 30-50% of people with ADHD (ADD) have other significant psychiatric comorbidities. Consider screening patients for the following:
  • Family history: Inquire about a family history of ADHD (ADD) and of the coexistent conditions listed under History of present illness.
  • Social history: Inquire about the following:
    • Home and family interactions consistent with ADHD (ADD)
      • Disorganization of personal space is the norm.
      • Anger or rage reactions are prevalent.
      • The child usually seems most awake in the late evening.
      • Awakening the child for school causes major problems.
      • The child is often unable to complete what appear to be developmentally appropriate chores.
      • Homework organization and completion are often a problem. 
      • High activity level is noted.
      • Completion of multistep directions is difficult.
      • Losing or forgetting material or conversations is observed.
    • Problems with the legal system
      • Arrests
      • Traffic tickets
      • Motor vehicle accidents
    • School performance
      • Report cards
      • Reprimands or notes sent home
      • Homework completion and/or turning homework in on time
      • Extracurricular activities
    • Family dysfunction
      • Drug abuse, alcohol abuse, or both
      • Parent(s) with ADHD (ADD)
      • Physical abuse
      • Sexual abuse
      • Recent death of loved one or friend
      • Severe chronic illness
      • Severe financial problems
    • Social skills
      • Friendships
      • Group cohesion
      • Strengths and interests
  • Pregnancy, potential for pregnancy, or safe-sex practices
    • Previous intercourse
    • Birth control
    • Condom use
  • Work performance
    • Type of work
    • Promptness
    • Overall work performance
  • Abuse of substances by patient or his or her friends (if the patient is an adolescent)
    • Alcohol
    • Caffeine
    • Marijuana
    • Other illicit drugs
    • Snorting stimulants
    • Prescription medications
    • Tobacco (eg, cigarettes, chewing tobacco, snuff)

Physical

A focused physical examination is recommended if none has been performed within the last year. Although a child or adolescent with ADHD (ADD) may exhibit few symptoms in a clinical setting, careful observation of behavior is important.

  • Vital signs
    • Height
    • Weight
    • Blood pressure
    • Pulse
  • General appearance
    • Fidgeting
    • Impulse control
    • State of arousal
  • Mental status examination
    • Affect
    • Cognition
    • Speech patterns
    • Thought patterns

Causes

At present, genetic loading appears to be the primary and perhaps only cause of ADHD (ADD). However, many environmental factors have been correlated with ADHD (ADD), and future research may prove these to be etiologic factors. Morbidity, as evidenced by signs and symptoms in people with ADHD (ADD), may be strongly correlated with the patient's home and school environments.

  • Genetic causes
    • Family, twin, adoption, and segregation analysis, as well as molecular genetic studies, show that ADHD (ADD) has a substantial genetic component. Molecular genetic studies have revealed several genes that appear to be associated with ADHD (ADD) because of their effect on dopamine receptors, dopamine transport, and dopamine beta-hydroxylase.
    • Research by the NIHM has shown that variants of the gene for catecho-O-methyltransferase (COMT) are associated with different levels of prefrontal dopamine activity. COMT metabolizes dopamine.
    • People with the val/val variant metabolize dopamine rapidly. Because fast metabolism of a substrate decreases the amount of substrate that is biologically available, these people have reduced prefrontal dopamine activity. This reduction, in turn, impairs prefrontal information processing.
    • Individuals with the val/met variant have fairly efficient prefrontal function.
    • Patients with the met/met variant have the most efficient prefrontal function. In fact, this variant results in an enzyme that is 3-4 times weaker than the product of the val/val variant.
  • Environmental causes: No environmental causes have been clearly identified. However, problems with pregnancy (including cigarette smoking during pregnancy) and/or delivery, head injuries, toxin exposure, heavy marijuana use beginning in early adolescence, marital or family dysfunction, and low social class have all been associated with ADHD (ADD).

More on Attention Deficit Hyperactivity Disorder

Overview: Attention Deficit Hyperactivity Disorder
Differential Diagnoses & Workup: Attention Deficit Hyperactivity Disorder
Treatment & Medication: Attention Deficit Hyperactivity Disorder
Follow-up: Attention Deficit Hyperactivity Disorder
References
Further Reading
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References

  1. APA. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association Press; 1994:78-85.

  2. Brown TE. Brown ADD Scales. San Antonio, TX: Psychological Corp; 1996:5-6.

  3. Elia J, Ambrosini PJ, Rapoport JL. Treatment of attention-deficit-hyperactivity disorder. N Engl J Med. Mar 11 1999;340(10):780-8. [Medline].

  4. Hunt RD, Paguin A, Payton K. An update on assessment and treatment of complex attention-deficit hyperactivity disorder. Pediatr Ann. Mar 2001;30(3):162-72. [Medline].

  5. Johnson TM. Evaluating the hyperactive child in your office: is it ADHD?. Am Fam Physician. Jul 1997;56(1):155-60, 168-70. [Medline].

  6. Millichap JG. Etiologic classification of attention-deficit/hyperactivity disorder. Pediatrics. Feb 2008;121(2):e358-65. [Medline].

  7. Nadeau KG, Littman E, Quinn P. Understanding Girls With AD/HD. Springfield, MD: Advantage Books; 2000.

  8. Ramchandani P, Joughin C, Zwi M. Attention deficit hyperactivity disorder in children. Clin Evid. Jun 2002;262-71. [Medline].

  9. Rappley MD. Clinical practice. Attention deficit-hyperactivity disorder. N Engl J Med. Jan 13 2005;352(2):165-73. [Medline].

  10. Reeves G, Schweitzer J. Pharmacological management of attention-deficit hyperactivity disorder. Expert Opin Pharmacother. Jun 2004;5(6):1313-20. [Medline].

  11. Spencer TJ, Biederman J, Wilen T. Pharmacotherapy of ADHD with antidepressants. In: Barkley RS, ed. Attention Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment. 2nd ed. New York, NY: Guilford Press; 1998:552-63.

  12. Wolraich ML, ed. The Classification of Child and Adolescent Mental Diagnoses in Primary Care: Diagnostic and Statistical Manual for Primary Care (DSM-PC) Child. Elk Grove, IL: American Academy of Pediatrics; 1996.

  13. Wilens TE. Straight Talk about Psychiatric Medications for Kids. New York, NY: Guilford Press; 2002.

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Further Reading

Additional resources on attention-deficit/hyperactivity disorder (ADHD) are available at Medscape's Attention Deficit/Hyperactivity Disorder (ADHD) Resource Center.

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Keywords

attention deficit hyperactivity disorder, AD/HD, ADD, ADD/ADHD, ADHD, attention deficit disorder, attention deficit disorder with and without hyperactivity, attention–deficit/hyperactivity disorder, attention-deficit hyperactivity disorder, hyperkinetic impulse disorder, hyperactive syndrome, hyperkinetic reaction of childhood, minimal brain damage, minimal brain dysfunction, undifferentiated attention deficit disorder, learning disorders, restless-legs syndrome, ophthalmic convergence insufficiency, depression, anxiety disorders, antisocial personality disorder

substance abuse disorder, conduct disorder, inattentive ADHD, inattentive ADD, pervasive developmental disorder, premenstrual dysphoric disorder, schizophrenia, psychotic disorder, mood disorder, anxiety dissociative disorder, personality disorder, major arterial disease, narrow-angle glaucoma, heart disease, heart palpitations, hepatic disease, hypertension, orthostasis, renal disease, seizure disorder, generalized anxiety disorder, GAD, obsessive-compulsive disorder, OCD, panic disorder, social phobia, oppositional defiant disorder, dissociative disorders, eating disorder, enuresis, encopresis, Asperger syndrome, posttraumatic stress disorder, PTSD, sleep disorder, Tourette syndrome, physical abuse, sexual abuse

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Contributor Information and Disclosures

Author

Susan Louisa Montauk, MD, Medical Director, The Affinity Center, Cincinnati; Professor, Departments of Family Medicine and Public Health Science, University of Cincinnati College of Medicine
Susan Louisa Montauk, MD is a member of the following medical societies: American Academy of Family Physicians and Society of Teachers of Family Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Christine A Mayhall, PhD, Clinical Psychologist, The Affinity Center
Christine A Mayhall, PhD is a member of the following medical societies: American Psychological Association
Disclosure: Nothing to disclose.

Medical Editor

Chet Johnson, MD, Medical Director, Child Development Unit, Department of Pediatrics, Professor, University of Kansas Medical Center
Chet Johnson, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

CME Editor

Carrie Sylvester, MD, MPH, Director of Education in Child and Adolescent Psychiatry, Professor, Departments of Psychiatry and Pediatrics, Northwestern University Medical School
Carrie Sylvester, MD, MPH is a member of the following medical societies: American Academy of Child and Adolescent Psychiatry, American Academy of Pediatrics, American Medical Women's Association, American Psychiatric Association, and American Society for Adolescent Psychiatry
Disclosure: Nothing to disclose.

Chief Editor

Caroly Pataki, MD, Professor of Clinical Psychiatry and Behavioral Sciences, Department of Psychiatry, Division Chair, Child and Adolescent Psychiatry, Director of Training, Child and Adolescent Psychiatry Residency Program, University of Southern California Keck School of Medicine
Caroly Pataki, MD is a member of the following medical societies: American Academy of Child and Adolescent Psychiatry, New York Academy of Sciences, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

 
 
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