ADHD — Chapter 8: Comprehensive Study Notes and Multiple-Choice Quiz Summary & Study Notes

🧠 Overview & Core Features

Attention-deficit/hyperactivity disorder (ADHD) is characterized by persistent, developmentally inappropriate patterns of inattention, hyperactivity, and impulsivity that cause impairment in major life activities. Characteristic behaviors vary widely across children, and symptoms often overlap and interact rather than existing in isolation.

✅ Diagnostic Criteria (DSM)

The DSM requires a persistent pattern of inattention and/or hyperactivity-impulsivity with functional impairment. Key points include:

• Symptom count: At least 6 symptoms in either the inattention or hyperactivity-impulsivity domain (for children).
• Duration: Symptoms present for at least 6 months.
• Age of onset: Several symptoms must be present before age 12.
• Settings: Symptoms must occur in two or more settings (e.g., home and school).
• Exclusion: Symptoms are not better explained by another disorder and interfere with social, academic, or occupational functioning.

🧩 Presentations & Specifiers

ADHD presentations describe the predominant symptom profile:

• Combined presentation (ADHD-C): Both inattention and hyperactivity-impulsivity criteria met. This is the most common and often most impairing presentation.
• Predominantly inattentive presentation (ADHD-PI): Primarily inattentive symptoms (daydreamy, slow processing, forgetful); often associated with internalizing features and learning problems.
• Predominantly hyperactive-impulsive presentation (ADHD-HI): Mostly hyperactivity-impulsivity; more common in preschoolers and less frequent in older children.

Specifiers include in partial remission (previously met full criteria but now subthreshold for ≥6 months with ongoing impairment) and current severity (mild, moderate, severe) based on symptom excess and degree of impairment.

🔎 Attention, Hyperactivity, and Impulsivity — Functional Profiles

Inattention involves difficulty sustaining attention—especially for repetitive or uninteresting tasks—and deficits across attentional domains such as attentional capacity, selective attention, distractibility, and sustained attention/vigilance (a core feature).

Hyperactivity includes excessive motor activity (fidgeting, inability to stay seated), constant motion, and non-goal-directed energy. It often appears as being “on the go” or talking excessively.

Impulsivity refers to difficulty inhibiting responses and controlling immediate reactions. It includes cognitive impulsivity (hasty thinking, disorganization), behavioral impulsivity (difficulty waiting, interrupting), and emotional impulsivity (low frustration tolerance, quick anger).

🧭 Associated Characteristics

Many children with ADHD show additional problems beyond core symptoms:

• Cognitive & executive function deficits: Problems organizing, prioritizing, sustaining and shifting attention, regulating alertness, and managing working memory and planning.
• Intellectual & academic: Most have at least average IQ but struggle to apply abilities in daily tasks. Lower productivity, grades, and higher rates of learning disorders (reading, spelling, math) are common.
• Distorted self-perception: Some show a positive illusory bias, overestimating competence; self-esteem varies by subtype.
• Speech & language: Formal language disorders, poor conversational turn-taking, excessive or loud speech, and production errors may occur.
• Motor & tic disorders: Up to 30–50% show motor coordination difficulties; tic disorders occur in about 20% of children with ADHD.
• Medical/physical: Elevated rates of sleep disturbance, asthma, bedwetting; greater accident proneness and risk-taking behaviors.
• Social/family: Higher rates of family stress, parental depression, sibling conflict; peers often reject children with ADHD, although positive friendships can buffer outcomes.

⚠️ Common Co-occurring (Comorbid) Disorders

Comorbidity is common:

• Up to 80% of children have at least one co-occurring psychological disorder.
• Oppositional defiant disorder (ODD) and conduct disorder (CD) frequently co-occur, but ADHD can occur without conduct problems.
• Anxiety disorders: Present in about 25–50% of cases and may worsen functional impairment.
• Mood disorders: 20–30% experience depression; early ADHD can be a risk factor for later depression.

📈 Prevalence, Sex, and Course

Prevalence estimates vary by method, but roughly 5–7% of school-age children are affected worldwide. ADHD is more often diagnosed in boys (clinical referral ratios around 6:1), though inattentive presentations in girls may be under-recognized.

Course across development:

• Signs may emerge in infancy but are not reliable for diagnosis then.
• Hyperactivity-impulsivity often appears in preschool; symptoms that persist ≥1 year in preschool predict later difficulties.
• School entry often unmasks attentional and behavioral difficulties; oppositional behaviors may escalate in middle childhood.
• Many children continue to have impairing symptoms into adolescence and adulthood; at least half of clinic-referred children show continued ADHD into adolescence.

🧬 Etiology & Neurobiology

ADHD is multifactorial with contributions from genetics, prenatal environment, brain structure/function, and neurochemistry:

• Genetic influences are strong; twin studies estimate heritability around 75% for inattention and hyperactivity-impulsivity.
• Prenatal/perinatal factors (e.g., maternal smoking, alcohol) are associated with increased risk but are likely contributory rather than strictly causal.
• Neurobiological findings implicate abnormalities in frontostriatal circuitry (prefrontal cortex and basal ganglia), delayed brain maturation, slightly reduced total cerebral and right hemisphere volumes (~3–4%), cerebellar differences, and altered thalamic regions.
• Functional differences include altered default mode network (DMN) regulation and impaired response inhibition, along with evidence of diminished arousal or arousability.
• Neurochemical studies point to relative deficits in dopamine and norepinephrine systems, though medication response does not prove causation.

💊 Treatment & Interventions

Evidence-based care is multimodal and individualized:

• Medication: Psychostimulants (e.g., methylphenidate, dextroamphetamine) are among the most effective short-term treatments and can normalize some functional connections while taken. Long-term benefits and outcomes remain under study.
• Parent Management Training (PMT): Teaches parents behavior management skills, ways to reduce family stress and arousal, and techniques to improve child compliance and daily functioning.
• Educational interventions: Classroom strategies (clear goals, response-cost systems, structured teaching) and school-based supports improve academic and behavioral outcomes.
• Intensive programs: Summer treatment, combined behavioral programs, and coordinated interventions (medication + PMT + social skills + school work) maximize gains, especially when disruptive behavior is sufficiently controlled to allow learning of new skills.

Treatment planning should consider symptom presentation, comorbid conditions, developmental level, family context, and functional impairment.