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N
Strong Evidence

ADHD Assessment

Understanding ADHD diagnostic criteria, what assessment should include, and what quality diagnosis looks like.

DSM-5-TR Diagnostic Criteria
The current standard for ADHD diagnosis. NICE guidelines align with these criteria.

ADHD diagnosis requires a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning and is present across multiple settings.

Inattention
Six or more symptoms (five for ages 17+)
  • 1Often fails to give close attention to details or makes careless mistakes
  • 2Often has difficulty sustaining attention in tasks or play activities
  • 3Often does not seem to listen when spoken to directly
  • 4Often does not follow through on instructions and fails to finish tasks
  • 5Often has difficulty organising tasks and activities
  • 6Often avoids or is reluctant to engage in tasks requiring sustained mental effort
  • 7Often loses things necessary for tasks and activities
  • 8Is often easily distracted by extraneous stimuli
  • 9Is often forgetful in daily activities
Hyperactivity & Impulsivity
Six or more symptoms (five for ages 17+)
  • 1Often fidgets with or taps hands/feet or squirms in seat
  • 2Often leaves seat when remaining seated is expected
  • 3Often runs about or climbs in inappropriate situations
  • 4Often unable to play or engage in leisure activities quietly
  • 5Is often "on the go" or acts as if "driven by a motor"
  • 6Often talks excessively
  • 7Often blurts out answers before questions are completed
  • 8Often has difficulty waiting their turn
  • 9Often interrupts or intrudes on others

Additional requirements

B

Several symptoms present before age 12 years

Symptoms must have been present in childhood, though diagnosis can be made at any age.

C

Symptoms present in two or more settings

E.g., home AND school/work. Can't just be a problem in one environment.

D

Clear evidence of clinically significant impairment

In social, academic, or occupational functioning. Having symptoms isn't enough.

E

Not better explained by another condition

Must not be explained by other mental health conditions, though ADHD can co-occur with other disorders.

ADHD presentations

Combined

Meets criteria for both inattention AND hyperactivity-impulsivity

Most commonly diagnosed. Classic ADHD presentation.

Predominantly Inattentive

Meets criteria for inattention but NOT hyperactivity-impulsivity

More common in girls. Often missed or diagnosed later. Previously called ADD.

Predominantly Hyperactive-Impulsive

Meets criteria for hyperactivity-impulsivity but NOT inattention

Less common. More often seen in younger children.

What assessment should include

Clinical interview
Detailed discussion about symptoms, history, and impact.
  • Current symptoms in detail
  • Developmental history
  • Family history of ADHD
  • Academic and social history
  • Previous interventions tried
  • Impact on daily functioning
Rating scales
Standardised questionnaires from multiple informants.
  • Parent rating scales (Conners, Vanderbilt, SNAP-IV)
  • Teacher rating scales
  • Self-report (older children/adults)
  • Scales should cover both settings
School information
Direct input from educational setting.
  • Teacher observations and concerns
  • Academic performance data
  • Behaviour in classroom
  • Social functioning at school
Medical review
Ruling out medical causes.
  • Vision and hearing screening
  • Sleep assessment
  • Thyroid function if indicated
  • Review of medications that might cause symptoms
Assessment of impairment
How symptoms affect daily life.
  • Academic functioning
  • Family relationships
  • Peer relationships
  • Self-esteem and wellbeing
  • Safety concerns

Note:

School information is essential. NICE guidelines state that ADHD cannot be diagnosed based on parent report alone. Teacher input is required. If a clinician diagnoses without school evidence, this is a red flag.

Differential diagnosis

Many conditions can look like ADHD or co-occur with it. Good assessment considers alternatives.

ConditionOverlapping featuresHow to distinguish
AnxietyDifficulty concentrating, restlessnessAnxiety causes concentration problems due to worry. ADHD concentration problems are interest-driven.
DepressionPoor concentration, low motivation, forgetfulnessDepression has mood component. ADHD symptoms predate mood changes.
Sleep disordersInattention, hyperactivity, irritabilitySleep problems can mimic ADHD. Always assess sleep. May co-occur.
AutismSocial difficulties, difficulty with transitions, executive function problemsDifferent pattern of social difficulties. Can co-occur (50%+ overlap).
Learning disabilitiesAcademic difficulties, avoidance of schoolworkLearning disabilities cause specific skill deficits. May co-occur.
Trauma/PTSDHypervigilance, concentration problems, emotional dysregulationTrauma symptoms are reactive to reminders. Need careful history-taking.

Who commonly gets missed?

Girls

Less hyperactive presentation. May mask symptoms. Teachers less likely to refer.

High IQ children

Compensate academically. Difficulties may not emerge until later. "Too smart to have ADHD" myth.

Adults

Childhood not documented. Symptoms attributed to character. Compensatory strategies mask difficulties.

Inattentive presentation

Doesn't disrupt class. May be seen as "dreamy" or "lazy". Less obvious than hyperactivity.

NICE Guidelines Summary (UK)
  • ADHD can be diagnosed in children aged 5 and over
  • Diagnosis requires comprehensive assessment by specialist
  • Multi-informant evidence essential (home and school)
  • Should screen for co-occurring conditions
  • Watch and wait not appropriate if significant impairment
  • Environmental interventions should be offered first
  • Medication can be considered for moderate-severe ADHD
Right to Choose (England)
In England, you have the legal right to choose where you receive your NHS-funded assessment.
  • GP must process valid Right to Choose requests
  • Can choose private provider for NHS-funded assessment
  • Must be on NHS pathway first
  • Waiting times often shorter
  • Assessment should meet same standards

Right to Choose applies to England only. Scotland, Wales, and Northern Ireland have different systems.

The key insight

ADHD diagnosis requires impairment, not just symptoms. Many people have some ADHD-like symptoms. Diagnosis is appropriate when those symptoms are persistent, present across settings, and cause significant problems in daily life.

Good assessment focuses not just on whether criteria are met, but on understanding how ADHD affects your specific child and what support they need.