Attention deficit hyperactivity disorder (ADHD) is a condition that affects behaviour. It develops in childhood and can continue into adulthood. Find out more about what ADHD is, the symptoms in both children and adults, and how the condition can be managed and treated.
ADHD is a neurodevelopmental disorder that can cause inattentiveness, hyperactivity, and impulsiveness. People with ADHD may seem restless, have a short attention span and difficulty concentrating, and act impulsively or recklessly.
The symptoms of ADHD are usually first noticed at an early age and most cases are diagnosed when children are six to 12 years old. However, some people may initially be misdiagnosed with another mental health condition such as bipolar disorder, or remain without a proper diagnosis until adulthood.
Many children can go through stages where they’re restless or have difficulty paying attention, but they don’t necessarily have ADHD. It’s important to speak to a health professional to discuss a diagnosis if a child may be affected.
The symptoms usually improve with age, but many adults will continue to experience problems and some may develop additional psychiatric disorders, most frequently mood and anxiety disorders, substance use disorders, or personality disorders. For example, ADHD and anxiety disorders have a 25% rate of occurring together, and co-occurrence with a reading disorder is also common.
People with ADHD may have problems with inattentiveness, hyperactivity, and impulsiveness, but not necessarily all three. There is a related condition, known as attention deficit disorder (ADD), which can cause problems with inattentiveness without the accompanying hyperactivity or impulsiveness associated with ADHD.
The reported rates of ADHD differ globally, ranging from 1% of school-age children in some countries to nearly 20% in others. The reason for this wide range of reported rates is unclear, but some experts claim it may be related to different case definitions.
An analysis of 175 research studies worldwide on ADHD prevalence in children aged 18 and under found an overall estimate of 7.2%. Screening of 11,422 adults aged 18–44 for ADHD in 10 countries in the Americas, Europe, and the Middle East showed an average prevalence of 3.4%.
The main symptoms of ADHD are related to inattentiveness, hyperactivity, and impulsiveness.
People with ADHD can have symptoms related to inattentiveness, hyperactivity, and impulsiveness but not necessarily all three. Symptoms can include:
Hyperactivity and impulsiveness:
These symptoms can lead to developmental issues such as poor educational achievement, problems with discipline, and a lack of social interaction.
Symptoms of ADHD are usually first seen at an early age and may become more noticeable as children start attending school. As children develop into adolescence, their hyperactivity may reduce; however, many will struggle with relationships and will display anti-social behaviours.
Inattention, restlessness, and impulsivity usually reduce with age, but many adults continue to experience problems.
One study found that almost half of people who had childhood ADHD continued to meet the full criteria for adult ADHD. Symptoms of inattention persisted in adults far more than hyperactivity/impulsivity. In adults, hyperactivity is more often internalised, and symptoms of inattention may be masked by anxiety symptoms or obsessive-like compensation strategies.
Hyperactivity and impulsiveness tend to be the main symptoms in children; this includes fidgeting, a short attention span, and being unable to play quietly.
The exact cause of ADHD is unknown. However, research has identified a number of factors that increase the risk of a child developing the condition.
There are thought to be several risk factors for ADHD, including:
Because there is no single cause for ADHD, anyone can develop the condition. It develops in childhood and it can run in families.
ADHD does not directly reduce life expectancy, but throughout an individual’s lifetime, ADHD can increase the risk of other psychiatric disorders and have a significant impact on overall quality of life. However, while ADHD can’t be cured, the treatments available should provide some relief from its symptoms.
There is no single test to diagnose ADHD, and its symptoms can be similar to those of other behavioural issues; this may lead to a delayed diagnosis.
A diagnosis of ADHD can only be made following a comprehensive evaluation by a clinician with expertise in the condition. The symptoms must have been long-lasting and must impact on the individual’s day-to-day life.
ADHD can’t be diagnosed through a simple physical or psychological test. A specialist needs to carry out a detailed assessment to make a diagnosis. The assessment may include:
ADHD was originally defined in children but is now recognised to persist into adulthood for some patients. Despite this, adult ADHD remains underdiagnosed. A diagnosis can be complicated by symptoms that overlap with other psychiatric disorders that might occur alongside ADHD. Screening tools have been developed for clinicians to identify which adults should be evaluated for ADHD, and clinical interviews and family histories allow for differentiation between ADHD and other psychiatric conditions that can occur at the same time.
Treatment and medication for ADHD can help to relieve the symptoms and make the condition easier to live with.
Although there’s no cure for ADHD, affected children and their parents can be given educational and wider support, advice, and guidance, alongside medical and behavioural therapies, to help them manage the effects of the condition.
For adults, medication is often the first line of treatment, with additional support from psychological therapy.
Research is continuing into the potential risks for developing ADHD. Advanced imaging technology has identified structural and functional differences in the brain between individuals with and without ADHD. The underlying brain anatomical and functional measures, as well as familial/genetic factors, are major foci of neuropsychiatric research.
Recent studies have suggested an important role of the gut-brain axis (GBA) and intestinal microbiota in modulating the risk of ADHD. It is thought that key biological mechanisms involved in the GBA may increase the risk of developing ADHD.
Work is also underway to help health professionals make decisions on the best courses of treatment for individuals. A review has been completed on the efficacy and safety of the expanding number of treatments available, including pharmacological and dietary interventions.