Attention Deficit & Hyperactivity Disorder

ADHD defined as at least 6 months of

  • Inattention,
  • Hyperactivity,
  • Impulsivity.

ICD requires all 3, DSM requires just 1.


  • social and/or academic difficulties not explained by anxiety or depression,
  • child should be under 7 yrs.

DSM does not give guidance on assessing severity. UK guidelines do not mention mild ADHD.

Commonly associated with peer rejection, increased risk of injury. Long term, less likely to enter higher education or find employment, more likely to have delinquent/criminal behaviour, more likely to smoke, use alcohol and illegal drugs.

There is high concordance for monozygotic twins, which supports a genetic cause. There are also MRI/PET lesions, which support a physical cause (cortical abnormalities in the frontal, temporal, and parietal lobes, Lancet 2003). It is 3 times more common in boys. It may be related to traumatic experience in infancy.

There are rating scales eg Conner’s ADHD index, which is 94% sensitive.

Examples of inattention:

  • Careless mistakes
  • Does not seem to listen when spoken to directly
  • Does not follow through instructions (NOT simply oppositional)
  • Avoids sustained mental effort
  • Loses things necessary for tasks/activites

Examples of hyperactivity/impulsivity:

  • Fidgets, squirms, leaves seat when expected to remain
  • Runs about, climbs in appropriate situations
  • Acts as if “driven by a motor”
  • Blurts out answers before question finished
  • Interrupts, intrudes on others

There should be impairments in at least 2 settings eg school and home.


Parent training programmes are effective for preschool children.

Methylphenidate, a dopamine agonist, is effective, esp for concentration, hyperkinesis and impulsiveness. Clonidine has been suggested.

Behaviour modification (NOT cognitive behavioural) is effective for age 6yr+ only when combined with medication.

Hyperactivity tends to improve over time, but there are associated antisocial behaviours and learning difficulties long term. The longest trial showed better performance up to 8yrs after entry (compared with baseline), but still underperforming compared with peers.

A diagnosis can help parents but also carries stigma: children with ADHD are perceived as lazier and less clever by peers, and teachers/parents have lower academic expectations.

BMJ 2013;347:18a