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
It is a common psychiatric disorder in childhood, often persisting into adolescence and adulthood.
Epidemiology:
ADHD is estimated to affect 5-10% of school-aged children worldwide
Prevalence varies by diagnostic criteria and methodology
Boys are more frequently diagnosed than girls, particularly with the hyperactive-impulsive subtype
Symptoms often begin before age 12 and can persist into adulthood.
Clinical Significance:
Untreated ADHD can lead to significant academic underachievement, social difficulties, behavioral problems, increased risk of injury, and comorbid psychiatric conditions like anxiety, depression, and learning disabilities
Accurate diagnosis and effective management are crucial for optimizing a child's development and well-being.
Clinical Presentation
Symptoms:
Core symptoms manifest as inattention: difficulty sustaining attention, forgetfulness, easily distracted, poor organization, avoidance of tasks requiring sustained mental effort, and losing things
Hyperactivity-impulsivity symptoms include: fidgeting, restlessness, excessive talking, difficulty waiting turns, interrupting others, and acting without thinking
Onset must be before age 12
Symptoms must be present in two or more settings (e.g., home and school).
Signs:
Physical examination is typically normal
Vital signs are generally unremarkable unless exacerbated by anxiety or medication
Behavioral observations during the interview may reveal restlessness, impulsivity, and distractibility
Signs of comorbid conditions like tics or learning difficulties may be present.
Diagnostic Criteria:
Diagnosis relies on DSM-5 criteria
It requires a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development
Symptoms must have been present before age 12 years, be present in two or more settings, and not be better explained by another mental disorder
A thorough clinical assessment by a trained professional is essential.
Diagnostic Approach
History Taking:
Comprehensive history includes developmental milestones, prenatal/perinatal events, family history of ADHD or other psychiatric disorders, school performance, social interactions, and parental concerns
Crucially, assess for symptom presence in multiple settings and their impact on daily functioning
Screen for comorbid conditions like anxiety, depression, oppositional defiant disorder, conduct disorder, and learning disabilities
Rule out medical conditions mimicking ADHD symptoms, such as hearing/vision impairments, thyroid dysfunction, sleep disorders, and lead poisoning.
Physical Examination:
A thorough physical examination is important to rule out medical causes of symptoms
This includes a general examination, neurological assessment (to exclude tics, developmental coordination disorder), vision and hearing screening, and assessment of growth parameters.
Investigations:
No specific laboratory tests or imaging studies definitively diagnose ADHD
Investigations are primarily used to rule out other conditions
These may include complete blood count (CBC), thyroid function tests (TFTs), lead levels, audiometry, and visual acuity testing if indicated by history or examination
Neuropsychological testing may be used in complex cases to further characterize cognitive profiles but is not routine for diagnosis.
Differential Diagnosis:
Key differentials include generalized anxiety disorder, oppositional defiant disorder, conduct disorder, learning disabilities, autism spectrum disorder, sleep disorders, hearing/vision impairment, intellectual disability, and effects of medication or medical conditions
Careful history and observation are critical to differentiate.
Management
Initial Management:
Management is multimodal and typically involves a combination of behavioral interventions and pharmacotherapy
The first step is education for parents, child, and teachers about ADHD
Behavioral interventions are crucial and include parent training, classroom management strategies, and academic support.
Medical Management:
Stimulant medications are the first-line pharmacological treatment for ADHD
Methylphenidate (e.g., Ritalin, Concerta) and amphetamines (e.g., Adderall, Vyvanse) are commonly used
Non-stimulant options include atomoxetine, guanfacine, and clonidine
- Methylphenidate (MPH):
- Immediate-release (IR): Start with 0.3 mg/kg/day divided into 2-3 doses, titrating up every 2-7 days
Maximum dose typically 1 mg/kg/day or 60 mg/day
- Extended-release (ER/LA/LA): Start with equivalent IR dose and titrate up
Common starting doses 18-20 mg once daily
Maximum typically 60 mg/day
- Amphetamines (AMP):
- Mixed amphetamine salts (MAS): Start with 0.15-0.3 mg/kg/day divided into 2-3 doses, titrating up
Max dose typically 0.5 mg/kg/day or 40 mg/day
- Lisdexamfetamine (LDX): Start with 30 mg once daily, titrating up to 70 mg once daily
- Atomoxetine: A selective norepinephrine reuptake inhibitor
Start with 0.5 mg/kg/day, titrating up to 1.2 mg/kg/day (max 1.4 mg/kg/day or 100 mg/day)
It has a delayed onset of action
- Alpha-2 Adrenergic Agonists (Clonidine, Guanfacine): Used as adjuncts or alternatives, particularly for hyperactivity, impulsivity, and sleep disturbances
Start with low doses and titrate slowly
Titration typically involves gradually increasing the dose every 1-2 weeks based on symptom response, side effects, and functional improvement
Regular monitoring for efficacy and adverse effects is essential.
Behavioral Interventions:
Parent training programs (e.g., Parent-Child Interaction Therapy, Triple P) teach parents strategies for managing child behavior
School-based interventions include classroom accommodations (e.g., preferential seating, reduced workload, extra time for assignments) and behavioral plans
Social skills training can also be beneficial.
Supportive Care:
Ongoing monitoring of physical growth (height, weight), blood pressure, heart rate, and sleep patterns is crucial
Nutritional counseling may be necessary if appetite is significantly affected by medication
Regular follow-up appointments with the clinician are essential to assess treatment efficacy and manage any side effects
Collaboration with school personnel is vital for successful management.
Complications
Early Complications:
Common early side effects of stimulants include decreased appetite, weight loss, sleep disturbances (insomnia), headaches, stomachaches, and increased irritability
Cardiovascular effects like increased heart rate and blood pressure can occur but are usually mild at therapeutic doses.
Late Complications:
Long-term complications of untreated ADHD can include academic failure, social rejection, increased risk of substance abuse, personality disorders, criminal behavior, and occupational difficulties in adulthood
Paradoxically, stimulant medication adherence may be associated with a lower risk of substance abuse.
Prevention Strategies:
Early and accurate diagnosis, comprehensive multimodal treatment including behavioral strategies and judicious pharmacotherapy, and consistent monitoring are key to preventing long-term complications
Educating families about the chronic nature of ADHD and empowering them with management strategies are vital.
Prognosis
Factors Affecting Prognosis:
Prognosis is influenced by the severity of ADHD symptoms, the presence of comorbid conditions (especially conduct disorder, learning disabilities), the family's socioeconomic status and support system, and the effectiveness of treatment
Early intervention generally leads to a better outcome.
Outcomes:
With appropriate treatment and support, most children with ADHD can achieve good academic, social, and emotional outcomes
However, a significant proportion will continue to experience residual symptoms into adulthood, requiring ongoing management.
Follow Up:
Regular follow-up every 1-3 months during the initial phase of treatment, and then every 3-6 months once stable, is recommended
Monitoring should include symptom severity, functional impairment, medication adherence, adverse effects, and screening for comorbid conditions
Follow-up should extend through adolescence and into adulthood as needed.
Key Points
Exam Focus:
DSM-5 criteria for ADHD
Differentiate subtypes (predominantly inattentive, predominantly hyperactive-impulsive, combined)
First-line pharmacotherapy (stimulants vs
non-stimulants)
Dosing and titration principles for methylphenidate and amphetamines
Common side effects and their management
Importance of multimodal treatment including behavioral interventions.
Clinical Pearls:
Always rule out medical causes first
Start low and go slow with titration, assessing functional improvements, not just symptom reduction
Educate parents extensively
they are key to successful management
Monitor growth and cardiovascular parameters closely
Consider medication holidays only under strict guidance, if at all
Understand that ADHD is a chronic condition requiring lifelong management in many individuals.
Common Mistakes:
Diagnosing ADHD solely based on parent or teacher reports without corroboration or ruling out other causes
Prescribing medication without a comprehensive diagnostic workup
Inadequate titration or monitoring of medication
Relying solely on medication without incorporating behavioral interventions
Failing to screen for and manage comorbid conditions
Not reassessing the diagnosis and treatment plan periodically.