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Attention-Deficit/
Hyperactivity Disorder

A neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development.

  • 5-7%
    Prevalence
  • ~7
    Onset Age
  • 2:1
    Ratio
  • 70-80%
    Response Rate

DSM-5-TR Diagnostic Criteria

  • Predominantly Inattentive

    6+ inattention symptoms (5+ for ages 17+)

    • • Fails to give close attention to details
    • • Difficulty sustaining attention
    • • Does not seem to listen
    • • Does not follow through on instructions
    • • Difficulty organizing tasks
    • • Avoids tasks requiring sustained mental effort
    • • Loses things necessary for tasks
    • • Easily distracted
    • • Forgetful in daily activities

  • Predominantly Hyperactive-Impulsive

    6+ hyperactivity-impulsivity symptoms (5+ for ages 17+)

    • • Fidgets with hands/feet or squirms
    • • Leaves seat when remaining seated expected
    • • Runs/climbs inappropriately (restlessness in adults)
    • • Unable to engage quietly in leisure
    • • On the go or driven by a motor
    • • Talks excessively
    • • Blurts out answers
    • • Difficulty waiting turn
    • • Interrupts or intrudes on others

  • Combined Presentation

    Meets criteria for both inattention AND hyperactivity-impulsivity

    Most common presentation (~60% of diagnosed cases). Symptoms from both categories present simultaneously.

Assessment Protocols

Validated tools for screening and severity tracking

  • ASRS-5

    Adult ADHD Self-Report Scale

    6-item screener validated for adult ADHD detection in clinical settings.

    Scoring:

    4+ symptoms (often/very often) suggests ADHD; full 18-item version available for detailed assessment

    Time:2-5 minutes (screener), 5-10 minutes (full)

  • Conners 3

    Conners Detailed Behavior Rating Scales

    Multi-informant assessment for children/adolescents covering ADHD symptoms and related problems.

    Scoring:

    T-scores: <60 average, 60-64 high average, 65-69 elevated, 70+ very elevated

    Time:15-20 minutes per rater

  • CAARS

    Conners Adult ADHD Rating Scales

    Criterion-standard adult ADHD assessment with self-report and observer forms.

    Scoring:

    T-scores guide severity; DSM-5-TR symptom count aids diagnosis

    Time:10-15 minutes

  • BRIEF

    Behavior Rating Inventory of Executive Function

    Assesses real-world executive function deficits across 8 domains.

    Scoring:

    T-scores ≥65 clinically elevated; examines working memory, planning, organization

    Time:10-15 minutes

Causes & Etiology

  • Neurobiological

    • Frontostriatal circuit dysfunction (prefrontal cortex, basal ganglia)
    • Dopamine and norepinephrine dysregulation
    • Delayed cortical maturation (3-5 year lag in children)
    • Reduced volume in caudate nucleus, corpus callosum, cerebellum

  • Genetic

    • Heritability: 70-80% (strongest genetic component in psychiatry)
    • Polygenic risk involving 100+ genes
    • DRD4, DRD5, DAT1, 5-HTT genes implicated
    • First-degree relatives have 4-5x increased risk

  • Environmental

    • Prenatal exposure: nicotine, alcohol, lead
    • Prematurity and low birth weight
    • Traumatic brain injury in early childhood
    • Severe early deprivation (e.g., institutional rearing)

  • Neuropsychological

    • Executive function deficits: working memory, inhibition, planning
    • Delay aversion (preference for immediate rewards)
    • Temporal processing impairments
    • Arousal/activation regulation difficulties

Common Comorbidities

  • Oppositional Defiant Disorder (ODD)

    40-60%

    Especially in childhood ADHD; defiance often related to impulsivity and emotional dysregulation

  • Anxiety Disorders

    25-50%

    Common across ages; screen separately, as anxiety can mimic inattention

  • Major Depressive Disorder

    18-30%

    Often secondary to chronic impairment and low self-esteem from ADHD

  • Learning Disabilities

    30-50%

    Dyslexia, dyscalculia, dysgraphia commonly co-occur; require separate assessment

  • Substance Use Disorders

    15-25%

    Higher risk in untreated ADHD; self-medication hypothesis

  • Sleep Disorders

    25-50%

    Delayed sleep phase, insomnia, restless leg syndrome frequent

Evidence-Based Treatments

  • Stimulant Medications

    First-line

    Methylphenidate (Ritalin, Concerta) or amphetamines (Adderall, Vyvanse). Increase dopamine/norepinephrine.

    Evidence

    70-80% response rate; SMD about 0.8-1.0 in children, 0.5-0.8 in adults

    In practice

    Immediate and extended-release formulations; titrate to optimal dose

  • Non-Stimulant Medications

    First-line

    Atomoxetine (Strattera), guanfacine (Intuniv), clonidine. For stimulant non-responders or contraindications.

    Evidence

    Lower effect size than stimulants (atomoxetine SMD about 0.56 in children, 0.45 in adults)

    In practice

    Atomoxetine: 4-6 weeks for full effect; alpha-agonists for hyperactivity

  • CBT for ADHD

    Adjunct

    Structured therapy targeting organization, time management, emotional regulation, cognitive distortions.

    Evidence

    Moderate effect sizes; studied mostly alongside medication

    In practice

    Targets impairment that persists despite medication

  • ADHD Coaching

    Adjunct

    Goal-oriented support for executive function challenges, accountability, skill-building.

    Evidence

    Small studies suggest gains in daily functioning and goal attainment

    In practice

    Not a substitute for therapy; focuses on practical implementation

  • Behavioural Parent Training

    First-line (children)

    Teaches parents behaviour management techniques: positive reinforcement, token economies, time-out.

    Evidence

    Strong evidence for reducing ODD symptoms and improving compliance

    In practice

    Recommended before or alongside medication for children

  • School/Workplace Accommodations

    Essential

    504 plans or IEPs (schools), ADA accommodations (work): extended time, reduced distractions, assistive tech.

    Evidence

    Legally protected; evidence for specific accommodations is limited

    In practice

    Neuropsychological testing often required for formal accommodations

Try it with one client

Send a PHQ-9 or GAD-7 by secure link and read the scored result before the session.

Start

Attention-Deficit/Hyperactivity Disorder questions

  • What is ADHD?

    Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder defined in the DSM-5-TR (ICD-10 codes F90.0, F90.1, F90.2) by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development. Symptoms must be present before age 12, occur in two or more settings (home, school, work), and produce clinically significant impairment. Three presentations are recognized: predominantly inattentive, predominantly hyperactive-impulsive, and combined.

  • What are the symptoms of ADHD?

    Core symptoms cluster into two domains. Inattention symptoms include difficulty sustaining attention, careless mistakes, not following through on tasks, losing items, distractibility, and forgetfulness. Hyperactivity-impulsivity symptoms include fidgeting, restlessness, excessive talking, blurting answers, difficulty waiting turn, and interrupting others. Adults typically present with internal restlessness, executive function deficits, time blindness, and emotional dysregulation rather than overt hyperactivity. Six or more symptoms (five for adults 17+) in either domain meet the diagnostic threshold.

  • How is ADHD diagnosed?

    Diagnosis requires a clinician using DSM-5-TR criteria, typically a psychiatrist, psychologist, primary care physician, or psychiatric nurse practitioner. Validated screening scales support the workup: ASRS-5 (6 items, free) and CAARS for adults; Conners 3 and Vanderbilt for children with parent and teacher informants. Symptoms must be present before age 12, occur in two or more settings, and not be better explained by another condition. A full clinical evaluation rules out mimics like sleep disorders, thyroid dysfunction, anxiety, and substance use.

  • What causes ADHD?

    ADHD is among the most heritable psychiatric conditions, with twin heritability estimates around 70 to 80 percent. Risk is polygenic: genome-wide studies point to many common variants, and candidate genes such as DRD4 and DAT1 each carry small effects. Neurobiologically, ADHD involves frontostriatal circuit differences, dopamine and norepinephrine dysregulation, and delayed cortical maturation in children. Environmental contributors include prenatal exposure to nicotine, alcohol, or lead, prematurity, low birth weight, traumatic brain injury, and severe early deprivation.

Scientific Sources

Evidence-Based

  • ASRS Validation

    Kessler RC, Adler L, et al. The World Health Organization Adult ADHD Self-Report Scale (ASRS): a short screening scale. Psychol Med. 2005;35(2):245-256.

  • DSM-5-TR Criteria

    American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). 2022.

  • Stimulant Medication Efficacy

    Faraone SV, Biederman J. Efficacy of Adderall for Attention-Deficit/Hyperactivity Disorder: a meta-analysis. J Atten Disord. 2002;6(2):69-75.

  • Neurobiological Mechanisms

    Volkow ND, Wang GJ, et al. Evaluating dopamine reward pathway in ADHD. JAMA. 2009;302(10):1084-1091.

  • Genetic Studies

    Faraone SV, Larsson H. Genetics of attention deficit hyperactivity disorder. Mol Psychiatry. 2019;24(4):562-575.

  • Multimodal Treatment (MTA Study)

    MTA Cooperative Group. A 14-month randomized clinical trial of treatment strategies for ADHD. Arch Gen Psychiatry. 1999;56(12):1073-1086.