Attention deficit hyperactivity disorder Dr Trisha Macnair Dr Rob Hicks Poor concentration, hyperactivity and learning difficulties are some signs that a child or adult might have attention deficit hyperactivity disorder.

In this article

What is it? What causes it?

What are the symptoms? Who's affected?

What's the treatment? Advice and support

Attention deficit hyperactivity disorder (ADHD) is the most common childhood-onset behavioural disorder.

Those affected have a greatly reduced ability to maintain attention without being distracted, to control what they're doing or saying (because of impulsivity) and to control the amount of physical activity appropriate to the situation (that is, they're restless and fidgety).

ADHD is also called attention deficit disorder (ADD) or hyperactivity. The disorder shouldn't be confused with normal, boisterous childhood behaviour.

The brain fails to filter the huge amount of stimulation we receive every minute of every day

The cause of ADHD has not yet been fully explained but it may be due, in part, by an inherited imbalance of neurotransmitters (chemicals that transmit nerves signals in the brain). One of the main problems in ADHD seems to be that the brain fails to filter the huge amount of stimulation we receive every minute of every day.

An affected child is easily distracted and can't process information at a normal rate. The frontal lobes don't work as well as they should with processes such as decision making, and there may be imbalances in the brain chemicals noradrenaline and dopamine.

However, this is a generalisation - brain research shows a variety of different problems in ADHD, with individuals showing their own pattern of behaviour.

Genetic or hereditary factors are important - usually a parent or close relative also has the condition. Twin and genetic studies show several genes are likely to be involved. Evidence of brain dysfunction has been found in brain-imaging studies.

However, research has so far been unable to show consistent neurobiological differences between affected children and normal controls, so the syndrome remains controversial.

Diet may be a factor - parents have long claimed that food additives can aggravate hyperactive behaviour and research by the Food Standards Agency and Southampton University has shown that certain mixtures of artificial food colours, alongside sodium benzoate - a preservative used in ice cream and confectionary - are linked to increases in hyperactivity.

Symptoms include excessively, consistently and involuntarily having difficulty:

• Remaining seated when required
• Waiting turn in group situations
• Following instructions
• Playing quietly

Other common symptoms include:

• Shifting from one incomplete activity to another
• Interrupting others
• Engaging in physically dangerous activities without considering the consequences

Not everyone with ADHD has the same symptoms or is affected by each to the same degree. There are three types of people with ADHD:

• Predominantly hyperactive-impulsive
• Predominantly inattentive
• Combined (the majority of ADHD cases)

There's also a fourth type, which doesn't fit into any of the three categories, classified as 'ADHD not otherwise specified'.

These problems are pervasive and debilitating, sometimes to the degree that daily functioning becomes extremely difficult. They can affect education and disrupt family life.

While their intellect may be normal or advanced, more than half of children with ADHD have specific learning disabilities, such as dyslexia. Coping with the symptoms can mean underachievement and poor self-esteem.

Children with ADHD are also more likely to be depressed, anxious and obsessive

Children with ADHD are also more likely to be depressed, anxious and obsessive, and may have some problems with speech, language and coordination.

Other major disorders may accompany ADHD, including oppositional defiant disorder (arguing and intentional defying) and conduct disorder (major antisocial activity).

Hyperactivity may improve at puberty but the problems usually persist in some form throughout adult life - up to 60 per cent of children show ADHD behaviour in adulthood.

ADHD usually starts at about 18 months, but might not be diagnosed until later, even until adulthood.

It's estimated that ADHD affects five to ten per cent of children and adolescents in the UK, with up to one in 100 severely affected. Symptoms usually develop between the ages of three and seven, with boys more likely to be affected than girls. The condition can run in families.

Although children with ADHD are more likely to come from dysfunctional families, it's not caused by bad parenting or abuse. The condition may affect one of the parents, however, and interfere with their parenting skills.

Since it isn't clear why children develop ADHD, it's difficult to prevent. There's also no simple screening test to identify those people carrying genes that might increase susceptibility and antenatal screening isn't available.

Although there's no cure, early diagnosis and appropriate help at home can make a big difference. Diagnosis should be made by formal testing by someone with experience of the condition, such as an educational psychologist.

The most recent guidelines from NICE (the National Institute for Health and Clinical Excellence) recommend that the first steps in treatment include help with behaviour and stress management, and educational support. Parents of children with mild to moderate ADHD should be offered training sessions to teach them how to cope with and manage their child's behaviour. The children themselves should be offered psychotherapy or social skills training.

The next step is medication to help children concentrate and be less disruptive, but NICE recommend that, in school-age children with moderate ADHD, drugs should only be prescribed if behaviour management strategies alone don't work. However in those children with more severe ADHD, which disrupts all aspects of their life, medication can be used as a first line treatment. NICE also says that medication should not be used at all in children under the age of five.

The most effective are stimulant drugs, such as methylphenidate (trade name Ritalin), which improve a child's ability to focus. However, the response to these drugs is variable - some children are helped more than others.

In addition, research suggests that after a couple of years on stimulants, the drugs may no longer have a significant effect. So after this period of time, children are usually offered a trial period off their drugs to see if they still need them.

Like any medication, there may be side-effects. For example, recent research has focused on possible effects on growth in some children.

Modification of diet may help some children . Support for the family is also important.

With help, many people with ADHD manage to channel their energies with dramatic success.

National Attention Disorder Information and Support Service

Tel: 020 8952 2800
Email: info@addiss.co.uk
Website: www.addiss.co.uk

Hyperactive Children's Support Group

Tel: 01243 539966
Email: hacsg@hacsg.org.uk
Website: www.hacsg.org.uk

This article was last medically reviewed by Dr Rob Hicks in November 2007