Attention Deficit Hyperactivity Disorder (ADHD) Notes

ADHD Diagnostic Criteria - Definition: ADHD is characterized by a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development, as characterized by one or more of the following criteria.

Inattention

  • Criteria: Six (or more) of the following symptoms have persisted for at least 6 months, inconsistent with developmental level and negatively impacting social and academic/occupational activities:

    • Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities (e.g., overlooks or misses details, work is inaccurate).

    • Often has difficulty sustaining attention in tasks or play activities (e.g., has difficulty remaining focused during lectures, conversations, or lengthy reading).

    • Often does not seem to listen when spoken to directly (e.g., mind seems elsewhere, even in the absence of obvious distraction).

    • Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., starts tasks but quickly loses focus and is easily sidetracked).

    • Often has difficulty organizing tasks and activities (e.g., difficulty managing sequential tasks; difficulty keeping materials and belongings in order; messy, disorganized work; has poor time management; fails to meet deadlines).

    • Often avoids, dislikes, or is reluctant to engage in tasks requiring sustained mental effort (e.g., schoolwork or homework; for older adolescents and adults, preparing reports, completing forms, reviewing lengthy papers).

    • Often loses things necessary for tasks or activities (e.g., school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).

    • Is often easily distracted by extraneous stimuli (for older adolescents and adults, may include unrelated thoughts).

    • Is often forgetful in daily activities (e.g., doing chores, running errands; for older adolescents and adults, returning calls, paying bills, keeping appointments).

Hyperactivity and Impulsivity

  • Criteria: Six (or more) of the following symptoms have persisted for at least 6 months, inconsistent with developmental level and negatively impacting social and academic/occupational activities:

    • Often fidgets with or taps hands or feet or squirms in seat.

    • Often leaves seat in situations when remaining seated is expected (e.g., leaves his or her place in the classroom, in the office or other workplace, or in other situations where remaining in place is required).

    • Often runs about or climbs in situations where it is inappropriate (Note: In adolescents or adults, may be limited to feeling restless).

    • Often unable to play or engage in leisure activities quietly.

    • Is often “on the go,” acting as if “driven by a motor” (e.g., is unable to be or uncomfortable being still for extended time, as in restaurants, meetings; may be experienced by others as being restless or difficult to keep up with).

    • Often talks excessively.

    • Often blurts out an answer before a question has been completed (e.g., completes people’s sentences; cannot wait for turn in conversation).

    • Often has difficulty waiting his or her turn (e.g., while waiting in line).

    • Often interrupts or intrudes on others (e.g., buts into conversations, games, or activities; may start using other people’s things without asking or receiving permission; for adolescents and adults, may intrude into or take over what others are doing).

Additional Criteria

  • Several inattentive or hyperactive-impulsive symptoms were present prior to age 12 years.

  • Symptoms are present in two or more settings (e.g., at home, school, or work; with friends or relatives; in other activities).

  • There is clear evidence that the symptoms interfere with or reduce the quality of social, academic, or occupational functioning.

  • Symptoms do not occur exclusively during the course of schizophrenia or another psychotic disorder and are not better explained by another mental disorder (e.g., mood disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication, or withdrawal).

A Brief History

  • ADHD is frequently thought to be a “twenty-first century disorder,” suggesting it is caused by abundant stimuli from current information technology (e.g., TV, smartphones, social media).

  • However, ADHD-like symptoms were reported as early as 1902.

Early Reports of ADHD

  • Early reports primarily focused on children’s malfunctioning, targeting symptoms of hyperactivity and impulsivity.

  • Before DSM-II (Diagnostic and Statistical Manual of Mental Disorders, Second Edition), children were described as having minimal brain damage (MBD), later nuanced to minimal brain dysfunctioning.

Evolution of Diagnoses

  • DSM-II (1968): Defined “hyperkinetic reaction of childhood” characterized by hyperactivity.

  • DSM-III (1980): Renamed to “Attention Deficit Disorder” (ADD) recognizing inattention as part of the disorder.

    • Diagnosis could be made with or without hyperactivity.

  • DSM-IV (1994): Distinguished between subtypes:

    • ADHD-I: Predominantly inattentive

    • ADHD-H: Predominantly hyperactive-impulsive

    • ADHD-C: Combined subtype (children with both inattentive and hyperactive-impulsive symptoms).

  • DSM-5 (2013): Retains DSM-IV subtypes, referred to as presentations; ongoing debate regarding the validity of these distinctions.

Prevalence

  • Recent estimates suggest that about 6% - 7% of children worldwide have ADHD.

  • Prevalence rates vary dramatically between studies, ranging from 1% to 20% among school-aged children, partly due to a rise in clinical referrals and diagnoses over the past two decades.

  • Variation factors include:

    • Different diagnostic criteria between ICD and DSM.

    • Diagnostic criteria may be applied too loosely, leading to inflated prevalence rates.

Sex Differences

  • Males are two to three times more likely to be diagnosed with ADHD than females.

  • Females more likely to meet criteria for inattentive presentation, while males often have combined presentation, leading to potential underdiagnosis of females due to less disruptive behavior.

Developmental Course

  • Initially recognized as a childhood disorder, largely believed to remit in adolescence.

  • Recent literature indicates that symptoms can persist into adulthood.

  • Rates of persistence vary based on the definition used:

    • Faraone et al. (2006) data shows approximately 15% of ADHD patients met full criteria at age 25; approximately 65% were diagnosed with “ADHD in partial remission.”

  • Prevalence by age:

    • 5% in young adulthood

    • 3-4% in old age

Functional Impact

  • ADHD significantly impacts the patient's life and society:

    • Children with ADHD experience:

    • Poor social skills leading to conflicted peer relationships.

    • Low self-esteem.

    • Adverse academic outcomes.

    • Higher risk of injuries and accidents.

    • Adolescents with ADHD start smoking at an earlier age and engage in riskier sexual behavior.

    • Adults with ADHD face lower socioeconomic status, marital difficulties, and general health problems.

Academic Achievement

  • Children with ADHD typically score 7 to 15 points lower in IQ tests and show deficits on neuropsychological testing, leading to poor academic functioning.

  • Higher risk for school problems, including:

    • Suspension

    • Repeated grades

    • Disruptive behavior problems.

Comorbidity

  • Adults with lifetime ADHD show increased occurrences of antisocial behaviors such as theft, assault, vandalism, or disorderly conduct.

  • Higher rates of:

    • Depression

    • Anxiety disorder

    • Antisocial personality disorder

    • Substance use disorder

  • Work-related issues include:

    • Poor productivity

    • Absenteeism

    • General occupational underachievement or unemployment.

  • Economic impact estimated at 143 to $676 billion, primarily due to loss of productivity and income loss.

Current Diagnostic Issues

  • Both inattention and hyperactive/impulsive behaviors should be viewed as continua, ranging from normal to severely abnormal.

  • Patients typically exhibit more severe symptoms than examples from the normal population, with cut-offs between “normal variation” and “abnormal behavior” regarded as arbitrary.

Importance of Standard Criteria

  • Strict adherence to standard diagnostic criteria is imperative to avoid overdiagnosis.

  • Important criteria include:

    • Impairment

    • Pervasiveness

    • Differential diagnostics (e.g., symptoms not being present in multiple settings).

Challenges of Adult ADHD Diagnosis

  • Diagnostic criteria originally defined for children's behavior and require adaptation for adult symptoms (e.g., focusing on subjective feelings of restlessness instead of inappropriate hyperactive behavior).

  • Difficulty tracking the exact age of onset required for a diagnosis due to aging effects.

Standard Treatment of ADHD

  • Effective treatment includes behavioral therapy, medication, or a combination of both.

  • Treatment guidelines recommend:

    • Behavior therapy for preschool children or those with moderate symptoms.

    • Medication for severe symptoms or comorbidities, typically accompanied by psychoeducation about ADHD for both parents and children.

Behavioral Therapy

  • A well-established treatment for pediatric ADHD, based primarily on positive and negative reinforcement to increase desired behaviors and decrease undesired ones.

  • Evidence-based treatments target various settings including:

    • Behavioral parent training

    • Classroom management

    • Peer interventions.

  • Meta-analysis (Van der Oord et al., 2008) indicates behavioral therapy reduces the behavioral symptoms of ADHD and has moderate effects on comorbid opposition and conduct behavior as well as social outcomes.

Medication

  • Treatment for children and adults typically involves:

    • Stimulants (e.g., methylphenidate or Ritalin
      )
      that enhance dopamine neurotransmission in the brain.

    • Nonstimulants (e.g., atomoxetine or Strattera
      )
      that enhance norepinephrine neurotransmission in the brain.

Prevalence of Medication Use

  • The prevalence of stimulant use has dramatically increased.

  • Documented beneficial effects of stimulants and atomoxetine:

    • Ameliorates core ADHD symptoms.

    • Beneficial for comorbid oppositional defiant behavior, cognitive functions, and productivity.

  • Little evidence for long-term benefits beyond two years of use.

Tolerability and Side Effects

  • Stimulants and atomoxetine are generally well-tolerated, with common side effects being:

    • Headache

    • Decreased appetite

    • Insomnia

    • Abdominal pain.

  • Notably, medications can lead to reduced weight and height gain in children, usually due to appetite suppression.

  • Drug Holidays: Taking children off medication during weekends or holidays is often advised to normalize side effects such as growth issues.

Etiology and Risk Factors

Genetic Influences

  • Twin and adoption studies indicate high heritability rates, with about 76% of the variance in ADHD symptoms explained by genetic factors.

Environmental Risk Factors

  • Neurobiological Factors: Complications during pregnancy or delivery, such as:

    • Maternal smoking or alcohol use

    • Eclampsia

    • Fetal distress

    • Premature birth