Attention deficit hyperactivity disorder (ADHD): why do some children grow out of their disorder while others do not?

Around one in 20 children worldwide have attention deficit hyperactivity disorder (ADHD).¹ Children with ADHD can have serious difficulties, with schoolwork and relationships, for example. Adults with ADHD can face additional problems – with drugs, crime and unemployment, to name but a few. Around one third of children grow out of their disorder during adolescence, while others find their problems persist into adult life.² Researchers are trying to find out why, with the ultimate aim of helping more people overcome ADHD.

What's the problem and who does it affect?

Why doesn’t every child grow out of ADHD?

Around one in 20 children have ADHD.¹ The disorder usually starts in early childhood. Children with ADHD tend to be overactive and impulsive, with a short attention span. They may seem restless, are easily distracted and often fidget constantly.

Children with ADHD can face serious difficulties. They can have trouble with schoolwork, meaning they underachieve academically. They can find it hard to avoid common hazards and can have problems forming positive relationships with both their friends and their family.

During adult life, people with ADHD can suffer from additional, sometimes severe problems. They may become addicted to drugs or get involved in crime, they can find it difficult to hold down a job, and they can have wide-ranging emotional and social difficulties, as well as personality disorders.

Both medical and psychological treatments can help control symptoms. Around one third of children seem to grow out of their disorder during adolescence, but the others find their ADHD persists into adult life. A key question is ‘Why?’ Finding the answer could lead to ways to help more children overcome ADHD.

What is the project trying to achieve?

ADHD: delving into the brain

The researchers are investigating why some children with ADHD grow out of their disorder during adolescence while others do not.

Around 400 adolescents and young adults, aged 15-25, are taking part in the study. Some 100 were diagnosed with ADHD during childhood, the others are their siblings, and pairs of siblings who do not have the disorder. They all took part in a study seven years earlier, meaning there is detailed information on their development during childhood.

The researchers are studying how the volunteers’ brains are developing, and how they are functioning, looking for differences between children who recover from their ADHD as they get older and those whose disorder persists. The researchers hope to identify new ways to predict whether or not children are likely to grow out of their ADHD.

The researchers are using a variety of tests, including EEG, or electroencephalography, which measures brain activity non-invasively using electrodes placed on the scalp. They are also assessing the volunteers’ IQ, and gathering detailed information about what sort of symptoms their ADHD is causing and how their lives are being affected.

What are the researchers' credentials?

We do not provide medical advice. If you would like more information about a condition or would like to talk to someone about your health, contact NHS Choices or speak to your GP.

The researchers are leading experts in how risk factors for ADHD change the way the brain functions, and in studying how brain processes and behaviour develop and change in children with ADHD over time. They have much experience of working with children with ADHD. They have also researched inattentiveness, over-activity and impulsivity – the key symptoms of ADHD – in children who do not have the disorder.

The researchers have successfully completed several large-scale studies on ADHD, have published extensively on this topic and are regularly invited to speak at international conferences.

The researchers have complimentary expertise that is perfect for this study – in using EEG to study brain function in ADHD, in clinical and genetic aspects of ADHD, and in the complex statistical analyses needed to interpret the data that is being generated in this project.

The research is taking place at the MRC Social, Genetic and Developmental Psychiatry Centre of Institute of Psychiatry, King’s College London. The centre houses a state-of-the-art EEG laboratory, which is a key resource for this project.

Who stands to benefit from this research and how?

Helping more children overcome ADHD

The project aims to benefit the large numbers of children with ADHD who don’t grow out of their disorder. The number of adolescents treated for ADHD, and requiring transition to the care of adult mental health services, is increasing.³

The researchers hope to find new ways to predict whether or not children with ADHD are likely to grow out of their disorder. They hope to learn more about why some children grow out of ADHD, while others do not. Do some children, perhaps, learn to compensate for the underlying impairments in the way their brain functions? If so, could we train children with persistent problems how to compensate for their ADHD too?

Ultimately, the researchers hope their work will guide the development of new treatments that will help children with ADHD avoid the serious problems that are linked to the disorder in adolescence and adulthood – problems such as underachievement, dangerous driving, depression, antisocial behaviour, substance abuse and involvement in crime.

Helping more children to overcome ADHD as they grow up could also reduce the major clinical and economic burden that the disorder places on society.

References

1. Polanczyk G, de Lima MS, Horta BL, Biederman J, Rohde LA. The worldwide prevalence of ADHD: a systematic review and metaregression analysis. Am J Psychiatry 2007; 164 (6):942-8.
2. Faraone SV, Biederman J, Mick E. The age-dependent decline of attention deficit hyperactivity disorder: a meta-analysis of follow-up studies. Psychol Med 2006;36(2):159-65.
3. Wong IC et al. Cessation of attention deficit hyperactivity disorder drugs in the young (CADDY)--a pharmacoepidemiological and qualitative study. Health Technol Assess 2009; 13(50), iii-iv, ix-xi, 1-120.