About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Onset in childhood (<12 years) with symptoms persisting into adulthood — often undiagnosed until adult life
- Three presentations: predominantly inattentive, predominantly hyperactive-impulsive, or combined (most common)
- Adults: inattention often predominates over hyperactivity. Presents as disorganisation, procrastination, forgetfulness, difficulty with sustained attention
- First-line drug in adults: lisdexamfetamine (NICE NG87). Alternatives: methylphenidate, dexamfetamine, atomoxetine (non-stimulant)
- Before starting stimulants: baseline BP, HR, weight, cardiovascular assessment, ECG if history/family history of cardiac disease
- Common comorbidities: anxiety, depression, substance misuse, personality disorder, sleep disorders, ASD
Overview
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition characterised by a persistent pattern of inattention, hyperactivity, and impulsivity that interferes with functioning and development. Symptoms must have been present before age 12 and cause impairment in ≥2 settings (work, home, social). While historically viewed as a childhood condition, it is now recognised that 60–70% of children with ADHD continue to meet criteria in adulthood, though the presentation often evolves — hyperactivity tends to decrease while inattention and executive dysfunction persist. Adult ADHD is frequently undiagnosed, misdiagnosed as anxiety or depression, and associated with significant functional impairment, relationship difficulties, occupational underachievement, and substance misuse.
Epidemiology
ADHD has a prevalence of approximately 3–4% in adults (UK estimates). It is more commonly diagnosed in males in childhood (3:1 ratio) but the ratio is closer to 1.5:1 in adults — females are often diagnosed later due to predominantly inattentive presentation being less disruptive and less recognised. There is a strong genetic component (heritability ~75%). Risk factors include family history, low birth weight, prematurity, prenatal tobacco/alcohol exposure, and psychosocial adversity. Comorbidity is the rule rather than the exception: anxiety (50%), depression (40%), substance misuse (25%), personality disorder, sleep disorders, and ASD frequently coexist.
Clinical Features
Symptoms
Inattention: difficulty sustaining focus, easily distracted, frequently loses things, forgetful in daily activities
Poor organisation: difficulty managing time, meeting deadlines, completing tasks, maintaining order
Hyperactivity (in adults): internal restlessness, inability to relax, fidgeting, excessive talking
Impulsivity: interrupting others, making hasty decisions, difficulty waiting, impulsive spending
Emotional dysregulation: low frustration tolerance, irritability, mood lability, impatience
Chronic underachievement despite ability — "not meeting potential"
Relationship difficulties, frequent job changes, driving infractions
Signs
Restlessness, fidgeting during consultation
Difficulty maintaining thread of conversation, tangential, loses track
Arrives late, disorganised, may forget appointments
No specific physical signs — diagnosis is clinical, based on history
Investigations
First-line
Clinical assessmentDetailed developmental and psychiatric history. Symptoms present from childhood (<12 years), pervasive (≥2 settings), and causing current impairment
ASRS (Adult ADHD Self-Report Scale)Screening tool — 18 items based on DSM-5 criteria. Part A (6 items) is the screener
Collateral historyInformation from family member or partner about childhood symptoms and current functioning. School reports if available
Second-line
Screen for comorbiditiesDepression (PHQ-9), anxiety (GAD-7), substance misuse (AUDIT/DAST), sleep disorders
Baseline cardiovascular assessmentBP, HR, family cardiac history. ECG if cardiac history or family history of sudden death, cardiomyopathy, channelopathies
Specialist
Specialist ADHD assessmentDiagnosis should be made by a specialist (psychiatrist or appropriately qualified healthcare professional). Structured diagnostic interview (e.g. DIVA-5)
1
Non-pharmacological interventions
- Psychoeducation about ADHD for the individual and their family/partner
- Structured group or individual CBT-based programme for ADHD (organisational skills, time management, emotional regulation)
- Environmental adjustments: workplace accommodations, study support, structured routines
2
Pharmacological treatment (adults)
- First-line: lisdexamfetamine (NICE NG87). Start 30 mg/day, titrate in increments up to 70 mg/day
- Alternative stimulant: methylphenidate (immediate or modified release) — start 5 mg BD or 18 mg MR, titrate up
- Alternative stimulant: dexamfetamine — used if lisdexamfetamine and methylphenidate not tolerated
- Non-stimulant: atomoxetine (noradrenaline reuptake inhibitor) — if stimulants not tolerated/contraindicated/patient preference. Takes 4–6 weeks for effect
- Guanfacine: non-stimulant alternative (alpha-2 agonist) — licensed for children, sometimes used in adults off-label
3
Monitoring on stimulant medication
- BP, HR, weight: at baseline, after each dose change, then every 6 months
- Height (in young people): every 6 months — stimulants may reduce growth velocity
- Monitor for side effects: appetite suppression, weight loss, insomnia, anxiety, tics, cardiovascular effects
- Controlled drug (Schedule 2): prescribe with appropriate safeguards
4
Driving
- DVLA must be notified of ADHD if it significantly impacts driving ability
- Stimulant medication generally improves driving safety — patients should NOT stop medication to drive
Complications
- Occupational underachievement: Despite intellectual ability, poor organisation and impulsivity limit career progression
- Substance misuse: 25% comorbidity — self-medication with stimulants, cannabis, alcohol. Treatment of ADHD reduces substance misuse risk
- Road traffic accidents: Impulsivity and inattention increase driving risk — stimulant treatment reduces this
- Relationship difficulties: Impulsivity, emotional dysregulation, and inattention strain partnerships
- Mental health comorbidity: Anxiety, depression, emotional dysregulation — often mistaken for primary conditions
UKMLA Exam Tips
- 1Adult ADHD: inattention and executive dysfunction predominate over hyperactivity (which often becomes "inner restlessness")
- 2Symptoms must have been present from CHILDHOOD (<12 years) — adult-onset ADHD does not exist
- 3Lisdexamfetamine is first-line in ADULTS (NICE NG87). Methylphenidate is first-line in CHILDREN (for under 5s: non-drug first)
- 4Atomoxetine is non-stimulant — takes 4–6 weeks to work. Used if stimulants contraindicated or not tolerated
- 5Stimulants are Schedule 2 controlled drugs — monitor for misuse, especially if comorbid substance use disorder
- 6ADHD + substance misuse: treating ADHD reduces substance misuse risk — do not withhold treatment
- 7Screen for cardiac risk before stimulants: BP, HR, family history of sudden cardiac death. ECG if indicated
practicetest your knowledge on adhd in adultsApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — psychiatry and beyond.
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