Attention Deficit Hyperactivity Disorder in Children (Child ADHD)

Page 1 2 3

What is Attention Deficit Hyperactivity Disorder in Children?

ADHD Attention deficit hyperactivity disorder (ADHD) is a behavioural syndrome related to abnormal brain functioning. ADHD is characterised by symptoms such as impulsivity, hyperactivity and/or inattention. While these symptoms are experienced by all people from time to time, they are severe and persistent in those with ADHD, and interfere with an individual's normal functioning.

Children who suffer from ADHD often have difficulty functioning at school and in other social environments.

Caring for children with the condition can be disruptive to family life and often causes considerable stress for parents, siblings and others who live with them.

ADHD is most commonly diagnosed in children when they begin school.

Who gets Attention Deficit Hyperactivity Disorder in Children?

3D Animation on
ADHD

This animation brought to you by Blausen Medical Communications.
Contact Andrew Walbank.

Estimates of the percentage of children and adolescent who have ADHD 1.7% to 17.8%; however, most estimates lie between 5–10%. A recent study estimated that the global prevalence of ADHD is 5.3%. Boys are significantly more likely to be diagnosed with ADHD than girls – at least four out of every five cases of ADHD are diagnosed in boys. The incidence in different communities (e.g. Australia vs. United States) is thought to vary, however the variation might also be because different methods are used to diagnose ADHD.

Standard criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders are now used to diagnose ADHD throughout Australia.

Recent research using these criteria revealed that almost 9% of American children have ADHD. However, less than half had been diagnosed by a health professional and less than a third were receiving appropriate treatment. Thus there are likely many undiagnosed cases of ADHD in the North American community.

In Australia, the National Survey of Mental Health and Wellbeing reported that 11% of children and adolescents fulfilled the criteria for ADHD. On a national basis, 0.5% of 4–17 year olds were prescribed stimulant medications to treat the condition between June 2006 and May 2007. The proportion of children prescribed stimulants varied between states (e.g. in NSW, 1.5% of 4–17 year olds were prescribed stimulants in the period). Similar to other countries, the vast majority of diagnosed ADHD cases in Australia are boys. In the 2006–07 period, 15,466 males were prescribed stimulant medication, compared to 3872 females, a ratio of about 4:1.

There has been an increase in the reported number of children with ADHD in the past decade, and the prescription of stimulant medication to treat the condition has also increased. For example, in Australia from 1984 to 2000, the number of scripts issued for stimulant medications to treat ADHD increased by an average of 31% per year. However the proportion of children prescribed stimulant medication remains below the proportion of children with ADHD and this apparent increase in the rate of reported cases of ADHD is due to increased awareness amongst health professionals and the public on the condition.

Predisposing Factors

The exact cause of ADHD is unknown, but several factors are associated with ADHD development.

Genetic factors

ADHD Genetic influence is possible, as ADHD is known to run in families. Family studies show that 10-35% of immediate family members of children with ADHD are likely to have the disorder, and the risk to siblings is 35%. Identical twins are more likely to both be affected than non-identical twins. It has been found that a number of genes for the substances which transport messages from the brain do not work properly in individuals with ADHD, and these genes are inherited genetically.

Not all individuals with the genetic predisposition to ADHD will develop the disorder. Environmental factors also influence who does and who does not develop ADHD.

Environmental and family factors

Exposure during pregnancy with cigarettes, alcohol and other substances (e.g. cocaine) may increase the risk of ADHD. Maternal stress during pregnancy also increases the risk of ADHD in children. Preschool children with higher levels of lead in their bodies are also at higher risk of developing ADHD.

Chaotic parenting may increase the risk of developing ADHD, but the relationship between ADHD and parenting may result from both negative aspects of the child influencing the parents' behaviour, and of the parents influencing the child's behaviour.The children of parents who are more demanding, aversive, negative, controlling, intrusive, disapproving, power assertive and less rewarding are at greater risk of ADHD.

Acquired brain injury can also increase the risk of ADHD.

Children from lower socioeconomic classes have higher rates of ADHD, and are more likely to be undertreated for their disorder. The increased rates of ADHD in poorer children is thought to relate to greater exposure to factors which increase the risk of ADHD (e.g. tobacco exposure during pregnancy, childhood lead exposure, complications of pregnancy and delivery). In addition, the negative impact of ADHD on social, academic and career outcomes may cause ADHD sufferers to cluster in lower socioeconomic groups.

Congenital factors

Studies have shown a possible link between the use of cigarettes and alcohol during pregnancy, and the risk of ADHD in offspring. Maternal substance abuse (e.g. cocaine, nicotine) may also cause ADHD-like symptoms.

Pregnancy and delivery complications (e.g. prematurity) have also been linked with increased rates of ADHD.

Brain structure factors

Some studies suggest that ADHD is caused by a compromised structure in areas of the brain that relate to inhibition and attention. There is also evidence that the brain size of children with ADHD is slightly smaller than in children without ADHD.

Neurophysiological factors

ADHD symptoms may be a result of cognitive deregulation, where the child's behaviour results from insufficient forethought, planning and control, and leads to impulsive responses and higher error rates.

Children with ADHD may also respond more impulsively in order to complete tasks more quickly, and therefore avoid delays.

In a situation where the child is not in control (e.g. in a classroom where he/she is expected to behave in a certain way), the child could achieve control by either daydreaming (inattention) or by fidgeting (hyperactivity).

Dietary factors

ADHD ADHD has been linked to the intake of food additives, food colourings and refined sugar. These substances have been shown to exacerbate ADHD symptoms. Diets that exclude foods containing substances which worsen behavioural problems, such as the Australian-developed FAILSAFE diet, have been used as treatments for ADHD since the 1980s. While the association between diet and ADHD symptoms is clear, dietary interventions alone are not enough to treat the symptoms of ADHD, and are best used in combination with pharmacological and educational interventions.