Persistent inattention and/or hyperactivity-impulsivity present before age 12 with cross-setting impairment.
Also known as: ADHD, attention deficit, ADD, hyperactivity
Overview
A neurodevelopmental disorder characterized by a persistent pattern of inattention and/or hyperactivity-impulsivity interfering with functioning or development, with several symptoms present before age 12 and across >=2 settings.
Epidemiology
Childhood prevalence ~5-7%; adult prevalence ~2.5-4%. Male-to-female ratio ~2:1 in childhood; narrows in adulthood. Highly heritable (~75%).
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Question 1PsychiatryEasy
A 9-year-old boy with attention-deficit/hyperactivity disorder (ADHD) is brought to the clinic for follow-up. He was started on mixed amphetamine salts 3 months ago with good improvement in inattention at school. However, his mother reports continued irritability, angry outbursts, and physical aggression toward his younger sister at home that have not improved on stimulant therapy. Vital signs and physical examination are normal. Which of the following is the most appropriate next pharmacologic agent to add?
ABupropion
BLithium
CGuanfacine
DAtomoxetine
EFluoxetine
Reveal answer & full explanation
Correct answer: C — Guanfacine
ABupropion
BLithium
CGuanfacine✓
DAtomoxetine
EFluoxetine
Why guanfacine is correct
This child has ADHD with persistent emotional dysregulation, irritability, angry outbursts, and physical aggression despite an adequate stimulant trial.
Guanfacine (or clonidine) is an alpha-2 adrenergic agonist that is FDA-approved as adjunctive therapy with stimulants in children 6–17 years old.
Alpha-2 agonists reduce hyperactivity, impulsivity, irritability, and aggression by enhancing prefrontal cortex norepinephrine signaling.
AAP and AACAP guidelines endorse the stimulant + alpha-2 agonist combination for ADHD with significant impulsivity or oppositional/aggressive features.
Why the others are wrong
Fluoxetine — an SSRI used for pediatric depression and OCD, not for ADHD-related aggression.
Bupropion — has some off-label use as ADHD monotherapy and lowers seizure threshold; not the recommended adjunctive agent for aggression.
Lithium — a mood stabilizer reserved for pediatric bipolar disorder, not ADHD with aggression.
Atomoxetine — a nonstimulant ADHD medication that is FDA-approved as monotherapy and is usually substituted when stimulants fail or are not tolerated; it is not the approved adjunct to an effective stimulant and is not the targeted agent for aggression.
Question 2PsychiatryEasy
A 32-year-old man has long-standing difficulty with sustained attention, frequent careless errors, disorganization, time management problems, and easy distractibility. He reports that these problems have been present for as long as he can remember. Which diagnostic criterion is required for adult attention-deficit/hyperactivity disorder (ADHD)?
ASeveral symptoms present before age 12
BThree or more symptom domains
CSix or more inattentive symptoms
DImpairment confirmed by a collateral informant
EContinuous symptoms for at least 12 months
Reveal answer & full explanation
Correct answer: A — Several symptoms present before age 12
ASeveral symptoms present before age 12✓
BThree or more symptom domains
CSix or more inattentive symptoms
DImpairment confirmed by a collateral informant
EContinuous symptoms for at least 12 months
Why Several symptoms present before age 12 is correct
Attention-deficit/hyperactivity disorder (ADHD) DSM-5 criteria in adults: ≥5 symptoms of inattention and/or hyperactivity-impulsivity (≥6 required in children <17) present for ≥6 months
Several symptoms must have been present BEFORE AGE 12
Symptoms must be present in two or more settings (home, work, school, social) and cause significant impairment
Subtypes: predominantly inattentive, hyperactive-impulsive, or combined
True ADHD does not first manifest in adulthood, though it may not be diagnosed until then
Why the others are wrong
Continuous symptoms for at least 12 months — the duration requirement is at least 6 months, and the symptoms need not be continuous
Impairment confirmed by a collateral informant — collateral history is recommended to corroborate childhood onset but is not itself a required diagnostic criterion
Three or more symptom domains — the criterion is ≥5 symptoms (adults) in the inattention and/or hyperactivity-impulsivity domains, not three separate domains
Six or more inattentive symptoms — six or more symptoms in a domain is the DSM-5 threshold for children younger than 17; from age 17 the criteria require only five or more symptoms of inattention, or five or more of hyperactivity-impulsivity, so applying the pediatric count to this 32-year-old is a common error
Additional high-yield points
Adult ADHD is associated with academic underachievement, occupational difficulty, and increased substance use
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Frontostriatal and frontoparietal dysfunction with reduced dopaminergic and noradrenergic signaling. Delayed cortical maturation in prefrontal regions. Reduced default-mode suppression during attention tasks.
Learning disability — Domain-specific academic deficit without pervasive inattention
Autism spectrum disorder — Social communication deficits and restricted/repetitive behaviors; often co-occurs with ADHD
OSA / poor sleep — Daytime inattention from sleep fragmentation; screen with sleep history
Diagnostic workup
Diagnostic criteria
DSM-5-TR: (A) >=6 inattention and/or >=6 hyperactivity-impulsivity symptoms for >=6 months in children, or >=5 for individuals age 17 and older; (B) Several symptoms present before age 12; (C) Present in >=2 settings; (D) Clear interference with functioning; (E) Not better explained by another disorder. Specify combined, predominantly inattentive, or predominantly hyperactive-impulsive presentation. Validated rating scales: Vanderbilt (children), ASRS (adults), Conners.
Labs
TSH, CBC if suggested by history
Pre-stimulant: BP, HR; cardiac history including family history of sudden death; ECG only if cardiac concerns
First-line; lisdexamfetamine prodrug with lower abuse potential
Non-stimulant NRI
atomoxetine, viloxazine
Useful with anxiety, tics, SUD history; 4-6 wks to effect
Alpha-2 agonist
guanfacine ER, clonidine ER
Adjunct or monotherapy; helps sleep onset, tics; watch sedation/BP
ADHD pharmacotherapy classes and selection considerations.
Treatment
First-line
Behavioral parent training and classroom interventions — first-line in preschool age (4-5 years) and adjunct at all ages
Stimulant — methylphenidate, lisdexamfetamine, mixed amphetamine salts (first-line pharmacotherapy school-age and older); titrate to effect over weeks; methylphenidate blocks dopamine and norepinephrine reuptake transporters (DAT/NET), and amphetamines also promote DA/NE release
School accommodations (IEP/504); psychoeducation; sleep regularity; exercise
Adults: CBT for ADHD; coaching; organizational supports
Second-line / adjunct
Non-stimulant: atomoxetine (selective norepinephrine reuptake inhibitor, NRI), viloxazine; useful in tic disorder, anxiety, SUD history
Alpha-2 agonist: extended-release guanfacine, clonidine — FDA-approved (ages 6-17) as monotherapy or as an adjunct to stimulants, especially with residual impulsivity, irritability/oppositional or aggressive behavior, sleep onset issues, or tic disorder
Bupropion — off-label in adults with comorbid depression
Avoid prescribing immediate-release stimulants to patients with active SUD; use long-acting or non-stimulants and consider diversion risk
Substance use disorders, especially when untreated
Comorbid mood, anxiety, learning, and oppositional defiant disorders
Stimulant side effects: appetite suppression, growth slowing, insomnia, modest BP/HR increases, rare cardiac events in those with structural heart disease
Misuse and diversion
PANCE pearls
Cross-setting and pre-age-12 symptoms are required — recent onset in adulthood should prompt search for other causes (substance use, mood, sleep, cognitive decline).
Stimulants are more efficacious than non-stimulants but require monitoring for BP/HR, appetite, sleep, and growth.
Reassess every 6-12 months — many children continue to benefit into adulthood; some achieve symptom remission and may taper.
Routine pre-treatment ECG is not required in low-risk children per AAP; obtain ECG/cardiology referral with positive cardiac history or exam.
References
AAP 2019 — AAP Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of ADHD in Children and Adolescents (2019)
AACAP 2007 — Pliszka S; AACAP Work Group on Quality Issues. Practice Parameter for the Assessment and Treatment of Children and Adolescents With Attention-Deficit/Hyperactivity Disorder. J Am Acad Child Adolesc Psychiatry 2007;46(7):894-921
DSM-5-TR — American Psychiatric Association. DSM-5-TR (2022)
MTA Study — The MTA Cooperative Group. A 14-month randomized clinical trial of treatment strategies for ADHD. Arch Gen Psychiatry 1999
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.