ADHD | Notion

DSM-V defines ADHD as a condition incorporating features relating to inattention and/or hyperactivity/impulsivity that are persistent. Like many paediatric conditions, there has to be an element of developmental delay. For children up to the age of 16 years, six of these features have to be present; in those aged 17 or over, the threshold is five features (Table below).

Epidemiology

ADHD has a UK prevalence of 2.4%, about twice that of autism, and is more common in boys than in girls (M:F 4:1);
Most children are diagnosed between the ages of 3 and 7;
There is a possible genetic component.

Diagnostic Features

Inattention	Hyperactivity/Impulsivity
Does not follow through on instructions	Unable to play quietly
Reluctant to engage in mentally-intense tasks	Talks excessively
Easily distracted	Does not wait their turn easily
Finds it difficult to sustain tasks	Will spontaneously leave their seat when expected to sit
Finds it difficult to organise tasks or activities	Is often 'on the go'
Often forgetful in daily activities	Often interruptive or intrusive to others
Often loses things necessary for tasks or activities	Will answer prematurely, before a question has been finished
Often does not seem to listen when spoken to directly	Will run and climb in situations where it is not appropriate

Management

NICE stipulates a holistic approach to treating ADHD that isn't entirely reliant on therapeutics. Following presentation, a ten-week 'watch and wait' period should follow to observe whether symptoms change or resolve. If they persist then referral to secondary care is required. This is normally to a paediatrician with a special interest in behavioural disorders, or to the local Child and Adolescent Mental Health Service (CAMHS). Here, the needs and wants of the patient, as well as how their condition affects their lives should be taken into account, to offer a tailored plan of action.

Drug therapy should be seen as a last resort and is only available to those aged 5 years or more. Patients with mild/moderate symptoms can usually benefit from their parents attending education and training programmes. For those who fail to respond, or whose symptoms are severe, pharmacotherapy can be considered:

Methylphenidate is first line in children and should initially be given on a six-week trial basis. It is a CNS stimulant which primarily acts as a dopamine/norepinephrine reuptake inhibitor. Side-effects include abdominal pain, nausea and dyspepsia. In children, weight and height should be monitored every 6 months
If there is inadequate response, switch to lisdexamfetamine;
Dexamfetamine should be started in those who have benefited from lisdexamfetamine, but who can't tolerate its side effects.

In adults:

Methylphenidate or lisdexamfetamine are first-line options;
Switch between these drugs if no benefit is seen after a trial of the other.

All of these drugs are potentially cardiotoxic. Perform a baseline ECG before starting treatment, and refer to a cardiologist if there is any significant past medical history or family history, or any doubt or ambiguity.

Like most psychiatric conditions, whether adult or paediatric, a thorough history and clinical examination are key, especially given the overlap of ADHD with many other psychiatric and physical conditions.