Attention deficit hyperactivity disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) is a group of behavioural symptoms that include:

  • difficulty concentrating and paying attention
  • hyperactivity
  • impulsiveness

Symptoms of ADHD in children and teenagers

Symptoms of ADHD tend to be noticed at an early age. They may become more noticeable when a child's circumstances change, like when they start school.

The main symptoms of ADHD in children and teenagers are:


The main signs of inattentiveness are:

  • having a short attention span
  • being easily distracted
  • making careless mistakes
  • appearing forgetful
  • losing things
  • being unable to stick at tedious or time-consuming tasks
  • appearing to be unable to listen to or carry out instructions
  • constantly changing activity or task
  • having difficulty organising tasks
Hyperactivity and impulsiveness

The main signs of hyperactivity and impulsiveness are:

  • being unable to sit still, especially in quiet surroundings
  • constantly fidgeting
  • being unable to concentrate on tasks
  • excessive physical movement
  • excessive talking
  • being unable to wait their turn
  • acting without thinking
  • interrupting conversations
  • little or no sense of danger

Symptoms of ADHD in adults

If you're an adult with ADHD, you may find that:

  • you get easily distracted and find it hard to notice details, particularly with things you find boring
  • it's hard to listen to other people – you may find yourself finishing their sentences for them or interrupting them
  • it's hard to follow instructions
  • you find it hard to organise yourself – you start a lot of things without ever finishing them
  • you find it hard to wait
  • you fidget and can't sit still when there's nothing much going on
  • you're forgetful and tend to lose or misplace things
  • you easily get irritable, impatient or frustrated and lose your temper quickly
  • you feel restless or edgy, have difficulty turning your thoughts off
  • you find stress hard to handle
  • you tend to do things on the spur of the moment, without thinking, which gets you into trouble

Some people with ADHD have problems with inattentiveness, but not with hyperactivity or impulsiveness. This form of ADHD is also known as attention deficit disorder (ADD). ADD can sometimes go unnoticed because the symptoms may be less obvious.

Related conditions 

Some people might have other conditions alongside ADHD. 

Related conditions in children and teenagers with ADHD

Some children may also have signs of other problems or conditions alongside ADHD, like:

The symptoms of ADHD can improve with age. Although many adults diagnosed with the condition at a young age continue to experience problems.

Related conditions in adults with ADHD

ADHD in adults can occur alongside several related problems or conditions.

One of the most common conditions is depression. Other conditions that adults may have alongside ADHD include:

ADHD can also cause problems like difficulties with relationships and social interaction.

Causes of ADHD

The exact cause of ADHD isn't fully understood.

A combination of the following factors might be responsible:


ADHD tends to run in families. The genes you you inherit from your parents are a factor in developing the condition. The way ADHD is inherited is complex and isn't thought to be related to a single gene.

Brain function and structure

Research has identified some possible differences in the brains of people with ADHD.

Some studies involving brain scans have suggested that certain areas of the brain may be a different size in people with ADHD.

Other studies have suggested that people with ADHD may have a chemical imbalance in the brain. Or that some chemicals may not work properly.

Groups at risk

Certain people are also believed to be more at risk of ADHD, including people:

  • who were born prematurely (before the 37th week of pregnancy) or with a low birthweight
  • with epilepsy
  • with brain damage – which happened either in the womb or after a severe head injury later in life

Diagnosing ADHD

Speak to your GP if you think that you or your child may have ADHD.

If you're worried about your child, it may help to speak to their teachers before seeing your GP. This means you can find out if they have any concerns about your child's behaviour.

Your GP can't formally diagnose ADHD. They can discuss your concerns with you and refer you for a specialist assessment, if necessary.

Treating ADHD

Treatment for ADHD can help relieve the symptoms.

ADHD can be treated using medication or therapy. A combination of both is often best. Treatment is usually arranged by a specialist, like a paediatrician or psychiatrist.

Treatment of ADHD might include:


Medication might help you or your child concentrate better, be less impulsive and feel calmer. 


You might be offered therapy. This might be:

  • psychoeducation
  • behaviour therapy
  • parent training
  • education programmes
  • cognitive behavioural therapy
  • social skills training

There are other treatments that involve altering your diet or taking supplements.

Last updated:
03 May 2023