Overview
Definition:
Attention-Deficit/Hyperactivity Disorder (ADHD) is a chronic neurodevelopmental disorder characterized by persistent patterns of inattention and/or hyperactivity-impulsivity that interfere with functioning or development.
Epidemiology:
Affects approximately 5-10% of school-aged children globally
prevalence varies by diagnostic criteria and methodology
More common in boys than girls, though diagnostic rates in girls are increasing
Persistence into adulthood is common.
Clinical Significance:
ADHD significantly impacts academic performance, social relationships, and overall quality of life
Effective management, including appropriate stimulant titration and proactive side effect management, is crucial for optimizing outcomes and preventing long-term morbidities.
Clinical Presentation
Symptoms:
Inattention: Difficulty sustaining attention, easily distracted, forgetful, loses things, avoids tasks requiring sustained mental effort, does not seem to listen, trouble organizing tasks, makes careless mistakes
Hyperactivity/Impulsivity: Fidgets, leaves seat, runs/climbs excessively, unable to play quietly, "on the go," talks excessively, blurts out answers, difficulty waiting turn, interrupts others
Symptoms must be present before age 12 and in at least two settings (e.g., home, school).
Signs:
Observable restlessness, difficulty sitting still, frequent interruptions, impulsive behaviors
Assessment of developmental milestones and academic/social functioning is key
No specific physical signs, but underlying neurobiological differences are present.
Diagnostic Criteria:
Diagnosis relies on DSM-5-TR criteria, requiring a pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development
Comprehensive evaluation including standardized rating scales (e.g., Vanderbilt, Conners), clinical interviews, and collateral information from parents and teachers is essential.
Diagnostic Approach
History Taking:
Detailed history of symptom onset, duration, severity, and pervasiveness across settings
Assess for co-occurring conditions (anxiety, depression, learning disabilities, conduct disorder)
Inquire about family history of ADHD or psychiatric disorders
Screen for developmental delays and sleep disturbances.
Physical Examination:
General physical examination to rule out other medical conditions
Neurological examination to assess for gross motor or sensory deficits
Assess growth parameters (height, weight, BMI) as stimulants can affect appetite and growth.
Investigations:
No specific laboratory or imaging tests confirm ADHD
Investigations focus on ruling out differential diagnoses
Consider thyroid function tests, complete blood count, and assessment for lead poisoning if history is suggestive
Neuropsychological testing may be considered in complex cases or for co-occurring learning disabilities.
Differential Diagnosis:
Learning disabilities, anxiety disorders, depression, oppositional defiant disorder, conduct disorder, sleep disorders, sensory processing disorder, medical conditions (e.g., hyperthyroidism, anemia)
Differentiating features often lie in the pattern, context, and duration of symptoms.
Management
Initial Management:
Psychoeducation for family and child
Establish clear behavioral expectations and routines
Implement behavioral interventions (e.g., positive reinforcement, token economies)
Nutritional counseling and regular exercise promotion.
Medical Management:
Pharmacotherapy is a cornerstone
Stimulant medications (methylphenidate-based and amphetamine-based) are first-line
Start with low doses and titrate gradually based on efficacy and tolerability
Non-stimulants (e.g., atomoxetine, guanfacine, clonidine) may be used as alternatives or adjuncts
Dosing is weight-based or based on symptom response.
Stimulant Titration Protocol:
Methylphenidate: Start at 2.5-5 mg once or twice daily
titrate up by 5 mg increments every 3-7 days to target dose
Amphetamines: Start at 2.5-5 mg once daily
titrate up by 2.5-5 mg every 3-7 days
Dosing frequency depends on formulation (short-acting vs
extended-release)
Aim for symptom improvement with minimal side effects
Monitor weight, height, vital signs, and cardiovascular status regularly.
Side Effect Management:
Common side effects include decreased appetite, weight loss, sleep disturbances, headache, stomach ache, and irritability
Management: 1
Reduce dose or frequency
2
Switch to a different stimulant or non-stimulant
3
Optimize timing of doses (e.g., take dose with food)
4
For sleep issues: consider extended-release formulations, adjust timing, or use adjunctive melatonin/alpha-agonists
5
Monitor for serious adverse events (e.g., cardiovascular issues, tics, psychiatric exacerbations) and manage promptly, potentially involving discontinuation of medication.
Complications
Early Complications:
Sleep onset insomnia, transient appetite suppression, headache, gastrointestinal upset, increased irritability, or paradoxical worsening of symptoms if dose is too high
Rebound hyperactivity when medication wears off.
Late Complications:
Chronic growth suppression (though typically catch-up growth occurs), development or exacerbation of tics, cardiovascular effects (rare but important to monitor), substance use disorders (controversial, but poorly treated ADHD may be a risk factor), persistent academic and social difficulties if untreated or inadequately managed.
Prevention Strategies:
Careful titration and regular monitoring for side effects
Use of extended-release formulations
Combination therapy (medication plus behavioral interventions)
Screening for co-occurring conditions
Regular follow-up with healthcare providers
Educating parents on recognizing and reporting side effects.
Prognosis
Factors Affecting Prognosis:
Early diagnosis and effective treatment are associated with better outcomes
Severity of ADHD symptoms, presence of co-occurring disorders (especially conduct disorder), and family support significantly influence prognosis
Academic and social functioning improvements with consistent management.
Outcomes:
With appropriate management, most children with ADHD can achieve good academic, social, and emotional functioning
However, a subset may continue to experience significant challenges into adolescence and adulthood, requiring ongoing support and treatment.
Follow Up:
Regular follow-up appointments (e.g., every 1-3 months initially, then every 3-6 months once stable) are crucial
Monitor symptom control, medication adherence, side effects, growth, vital signs, and academic/social progress
Reassess diagnosis and treatment plan periodically, especially during developmental transitions.
Key Points
Exam Focus:
First-line stimulants: Methylphenidate and Amphetamines
Dosing: Start low, titrate slow
Monitor efficacy and side effects
Common side effects: appetite loss, sleep disturbance, irritability
Non-stimulants as alternatives/adjuncts: Atomoxetine, Guanfacine, Clonidine
Rule out co-occurring conditions.
Clinical Pearls:
Always start with psychoeducation and behavioral strategies before or concurrently with medication
Titrate in increments, waiting for a stable response before increasing
Be vigilant for growth, cardiovascular, and psychiatric side effects
Involve school personnel for comprehensive assessment and feedback
Consider formulations based on symptom timing and child's routine.
Common Mistakes:
Diagnosing ADHD solely based on teacher reports without comprehensive evaluation
Inadequate titration or premature discontinuation of medication
Neglecting to monitor for side effects or co-occurring conditions
Relying solely on medication without behavioral interventions
Failing to reassess treatment needs during developmental changes.