What is attention deficit hyperactivity disorder?

Attention deficit hyperactivity disorder (ADHD) is a developmental condition that can make it difficult for a person to concentrate and control their behaviour. It usually arises in early childhood, but can affect some people their entire lives.

It can be difficult to estimate how common ADHD is in the community, in part because there are different approaches to defining what ADHD is and how to diagnose it. International studies based on one approach (as set out in the Diagnostic and Statistical Manual of Mental Disorders) suggest around 5% of children and 2.5% of adults in the world have ADHD.1

Signs and symptoms

One of the challenges of diagnosing ADHD is that, as part of their normal behaviour, all children show some of the behaviours described as symptoms of ADHD some of the time. 

However, for children with ADHD, these behaviours occur more frequently, more severely and persist over time. They have a disruptive effect on many aspects of a child’s life, including family relationships, how they play and interact with other children and their education.

There are three main symptoms associated with ADHD:

  • Hyperactive behaviour. This can include restlessness, difficulty sitting still and a tendency to fidget. Children may be very physically active, running and climbing a lot;
  • Impulsive behaviour. This can include difficulties controlling behaviour. Children may tend to talk a lot and interrupt others or lose their temper easily, and;
  • Inattentive behaviour. This can include difficulty concentrating or following instructions. Children tend to have trouble finishing tasks, or may want to avoid tasks that require attention for more than short periods of time. They tend to be easily distracted.

Not all children with ADHD show all three of these types of behaviours. The severity of behaviours varies between children, as well as over time in individual children as they grow and develop.

Boy with ADHD seated at a desk, not attending his school work.

ADHD can cause inattentive behaviour.


There is no single cause of ADHD and there is still a great deal of debate about how aspects such as genetics, environmental factors (for example, exposure to lead) and early social experiences may contribute to the development of the condition. 

Risk factors

There are some medical conditions and circumstances in which ADHD symptoms may be more likely to occur. These can include:

  • Very low birth weight; 
  • Childhood trauma (including abuse, neglect, domestic violence and parental illness);
  • Brain injury (including damage that occurs during the pregnancy), and;
  • Genetic development disorders such as neurofibromatosis and fragile X syndrome.


Because not all children show all three main symptoms of ADHD, it is classified into three subtypes:

  • Inattentive, in which most of the symptoms are of the inattentive variety;
  • Hyperactive-impulsive, in which most of the symptoms are in the hyperactive and impulsive categories, and;
  • Combined, in which significant symptoms are displayed in the inattentive as well as the hyperactive and impulsive categories.

ADHD in adults

Many children who are diagnosed with ADHD have some symptoms and mental health problems that carry on into adulthood and require treatment and management. Other people may not be diagnosed until they are adults, but will generally have had symptoms from childhood.

Symptoms of ADHD in adults are similar to those displayed by children; however, they may cause different difficulties in adult life. For example, symptoms of inattentiveness may include forgetting appointments and erratic work habits. Impulsive behaviour can be associated with issues such as trouble managing money, drug or alcohol abuse, or an increased tendency to commit traffic infringements.

As with children, while all adults can sometimes display some of the behaviours described as ADHD symptoms, for adults with ADHD they are more severe and form a pattern of ongoing behaviour that has a disruptive effect on their lives.

Adults with ADHD can also tend to have a range of other mental health issues and conditions including poor self-confidence and low self-esteem, depression, anxiety, substance abuse and other behavioural disorders. In adults it is important to differentiate ADHD from bipolar disorder as the treatment for the latter is different.

Methods for diagnosis

Assessment and diagnosis of ADHD must be performed by an experienced specialist clinician such as a paediatrician, child psychologist or child psychiatrist. Your general practitioner can make an initial assessment, however, they will usually refer your child for further assessment if they suspect ADHD. Some general practitioners have special training in ADHD and can manage children with the condition.

For a child to be diagnosed with ADHD, symptoms and behaviours need to occur on a long-term basis (a minimum of six months).

Assessment for ADHD is complex and can include:

  • A medical examination to detect any underlying medical conditions;
  • A mental health assessment;
  • A developmental assessment to understand your child’s overall development compared to milestones expected for their age;
  • Assessment of your child’s situation and needs including family, culture and education, and;
  • Assessment of your child’s behaviour.

In order for this assessment to be comprehensive, your specialist may ask to talk to other family members and teachers about your child’s behaviour. They may also ask to review information such as school reports, or for your child to be observed at home or school.

In Australia, guidelines and approaches to diagnosing ADHD are evolving. Particularly with children who have mild symptoms, there can be different approaches to diagnosing the condition. If you have any concerns or questions about how ADHD is diagnosed, or your child’s diagnosis, you can discuss them with your specialist.

Diagnosis of adults

As with children, while a general practitioner can make an initial assessment, most adults will be referred to a specialist clinician, usually a psychiatrist, for full assessment and diagnosis.

A full medical assessment helps to determine whether there are any underlying medical conditions that may be contributing to your symptoms. Your specialist will ask you about your symptoms and may also ask to speak with your partner or other family members.

ADHD is only diagnosed if the symptoms create a serious disruption to your life.

Types of treatment

ADHD cannot be cured, but the goal of treatment is to help:

  • Reduce and manage disruptive behaviours so that they have less impact on the child’s wellbeing and development, and;
  • Support parents, carers and other family members.

There are a variety of management options for dealing with ADHD and the treatment can be tailored for each child’s specific circumstances and needs. Often a combination of approaches will be recommended in a management plan that may involve a range of healthcare professionals as well as the child’s family and their school.

Children who are being managed for ADHD often require regular review appointments to monitor how they are responding to treatment and whether or not changes need to be made. Your specialist will discuss how often your child’s management needs to be reviewed.

Controversy does exist around the use of medications to manage ADHD in children. Not all children with ADHD require medication and your specialist will discuss options with you to arrive at a management plan that is most suitable for your child. 

Family education and support

It can be very challenging to care for a child with ADHD. Disruptive behaviours can cause stress for parents and other family members. Information, counselling and programs are available to support parents and carers, to help them to understand ADHD and learn techniques to reduce and better manage disruptive behaviour.

Psychological management

Children with ADHD can have problems with low self-esteem and anxiety, as well as difficulty with relating to other children. Psychological treatments and counselling can help with these issues, as well as promoting skills for concentration.

Mental health practitioner talking with a young girl with ADHD and her mother.

Counselling programs can help with problems such as anxiety and low self-esteem.

Educational management

Schools and teachers play a vital role in helping children to manage ADHD and learn and develop to their potential.

Educational management options include:

  • Tailoring an education plan for your child’s particular needs that may include changing your child’s curriculum and aspects of how they learn, such as how homework is scheduled;
  • Providing learning materials tailored to your child’s needs;
  • Providing training in social skills to help improve your child’s relationships with other children, and;
  • Techniques for managing disruptive behaviours at school.

Training about ADHD is available for educators and you can work with your child’s school to make sure that they are aware of your child’s needs.

A male teacher assisting a boy with ADHD with his school work.

A supportive education plan is very important for children wtih ADHD.


Medications may be prescribed for children with ADHD, particularly those with more severe symptoms. Medications for ADHD are only prescribed under strict regulations and children who take them need to see their specialist regularly for review.

For very young children (those less than seven years of age), other management approaches will usually be tried first and medication used only if these have not been effective.


In Australia, psychostimulant medications such as methylphenidate and dexamphetamine sulphate, are prescribed for ADHD. Although these medications are called psychostimulants, they can have a calming effect on children with ADHD.

Evidence has shown that for children, psychostimulants can help to:

  • Reduce the main symptoms of ADHD;
  • Improve social skills, and;
  • Improve relationships with other children of their own age.

This evidence is based on children taking medication for up to three years. There may be benefits associated with taking these medications long-term, but it has not yet been proven.


Atomoxetine is a noradrenaline reuptake inhibitor. This means that it affects a chemical messenger in the brain called noradrenaline, helping it to be more effective. This medication may be prescribed for children with ADHD if psychostimulants are not suitable or effective.

Atomoxetine can cause serious side effects and children taking this medication must be closely monitored by their specialist.


It has been proposed that a range of foods and food additives worsen ADHD symptoms, for example, because of food allergies. However, current evidence does not support eliminating or restricting foods from your child’s diet in order to treat ADHD.

Children with ADHD have been shown to have lower-than-normal levels of polyunsaturated fatty acids (PUFAs) in their blood, particularly the omega-3 variety. Supplementation of the diet with fish oils rich in PUFAs has been trialled, but most trials have shown no or limited evidence of improvement of symptoms.

Nutrition is very important to children’s healthy growth and development and restricting foods from your child’s diet may mean they don’t receive all the nutrients and energy they need. As part of managing ADHD, you can discuss your child’s diet with your specialist or general practitioner. 

Alternative therapies

A range of alternative therapies have been suggested for treating ADHD. In some cases, their use has been controversial and there is little evidence available regarding their effectiveness. Some of these therapies include acupuncture, meditation, chiropractic, vision training, homeopathy, massage, biofeedback and sensory integration therapies.

Treatment of adults

Treatment of adults is similar to children. Psychostimulants such as methylphenidate and dexamphetamine sulphate may be recommended. Medication will usually be combined with other approaches such as learning about ADHD and how to manage it, psychological therapy, counselling and support groups. Your management plan will also take into account any other medical conditions or mental health problems that may be contributing to your symptoms.

Medications for ADHD are only prescribed under strict regulations. People who take them need to see their doctors regularly for review. There is the potential for drug abuse in adults, particularly with amphetamine-like compounds.

Potential complications

Side effects of psychostimulant medications

Common side effects of psychostimulant medications include:

Other less common side effects that have been reported include:

  • Slowed growth in children;
  • Dizziness;
  • Anxiety;
  • Restlessness, and;
  • Irritability and crying spells.

Psychostimulant medication can also cause increases in heart rate or blood pressure, although these are usually small and are monitored by your specialist.

Most of the side effects caused by stimulant medications can be reversed or managed. Letting your specialist know about them is an important part of managing ADHD.

Unmanaged ADHD

ADHD can have a serious impact on many aspects of a person’s life. It has been associated with:

  • Poorer performance at school and a lack of academic achievement;
  • Problems in relationships with peers and families, including increased conflict;
  • Poorer performance at work and an increased chance of unemployment, and;
  • Criminal activity.

Other developmental and mental disorders

There are a wide range of behaviour and mental health disorders that can cause similar symptoms to ADHD. Part of the assessment procedure is to identify the pattern of symptoms and provide an accurate diagnosis, so that the most effective management can be recommended.

In some cases, a person with ADHD may also be diagnosed with another disorder. Children with ADHD are also frequently diagnosed with other behavioural disorders, such as oppositional defiant disorder and learning problems, such as specific learning disorder.

Adults with ADHD are more likely than the general population to have a range of mental health problems including antisocial and personality disorders, anxiety, depression and substance abuse.


Symptoms of ADHD can reduce as a child grows and develops, but many children who are diagnosed with ADHD have some symptoms that may impact on their lives and require treatment as adults.


Because the causes of ADHD are not yet fully understood, it is unclear how the condition can be prevented. Early assessment and treatment of symptoms may help to minimise disruption to your child’s development and education. 

Last Reviewed: 03/10/2018

Reproduced with permission from Health&.