The symptoms of attention deficit hyperactivity disorder (ADHD) can be categorised into two sets of behavioural problems:
- symptoms of inattentiveness
- symptoms of hyperactivity and impulsiveness
It is not fully understood whether these problems are an extreme form of normal behaviour, or part of a separate range of behaviour.
Types of ADHD
A person with ADHD usually has symptoms characteristic of one of the three subtypes of the condition. The subtypes are:
- ADHD mainly inattentive
- ADHD mainly hyperactive-impulsive
- ADHD combined
If your child has symptoms of all three behavioural problems – inattentiveness, hyperactivity and impulsiveness – they may have ADHD combined, which is the most common subtype of ADHD.
Alternatively, if your child has symptoms of inattentiveness but not hyperactivity or impulsiveness, they may have ADHD mainly inattentive. This form of ADHD is also known as attention deficit disorder (ADD).
Childhood ADHD is more commonly diagnosed in boys than in girls, but this may be because disruptive behaviour, which the diagnosis may be partly based on, tends to be more common in boys than girls.
Girls with ADHD often have the mainly inattentive form of the condition, which may make them quiet and dreamy and can sometimes go unnoticed. It is therefore possible that ADHD could be underdiagnosed in girls, and could be more common than previously thought.
Symptoms in children and teenagers
The symptoms of ADHD in children and teenagers are well defined. The main symptoms of each behavioural problem are detailed below.
Inattentiveness
The main symptoms of inattentiveness are:
- a very short attention span
- being very easily distracted
- making careless mistakes, for example in schoolwork
- appearing forgetful or losing things
- being unable to stick at tasks that are tedious or time consuming
- being unable to listen to or carry out instructions
- being unable to concentrate
- constantly changing activity or task
- having difficulty organising tasks
Hyperactivity
The main symptoms of hyperactivity are:
- being unable to sit still, especially in calm or quiet surroundings
- constantly fidgeting
- being unable to settle to tasks
- excessive physical movement
- excessive talking
Impulsiveness
The main symptoms of impulsiveness are:
- being unable to wait for a turn
- acting without thinking
- interrupting conversations
- breaking any set rules
- little or no sense of danger
If your child has ADHD, their symptoms usually become noticeable before the age of seven, with a diagnosis usually made between the ages of three and seven.
ADHD can cause problems in a child's life, and can often lead to underachievement at school, poor social interaction with other children and adults and problems with discipline.
Related conditions in children and teenagers
Although it is not always the case, your child may also have other problems or conditions alongside ADHD. These are explained below.
Anxiety disorder
Some children with ADHD may have an anxiety disorder that causes them to worry and be nervous most of the time. Your child may also have physical symptoms, such as a rapid heartbeat, sweating and dizziness. See the Health A-Z topic about Anxiety for more information.
Oppositional defiant disorder (ODD)
Oppositional defiant disorder (ODD) is common among children with ADHD. It is defined by negative and disruptive behaviour, particularly towards authority figures such as parents and teachers.
Conduct disorder
Children who have conduct disorder have a tendency towards highly antisocial behaviour, such as:
- stealing
- fighting
- vandalism
- harming people
- harming animals
If your child is behaving in this way, book an appointment with your doctor as soon as possible.
Depression
It is possible for children with ADHD to become depressed as a result of their condition. See the Health A-Z topic about Depression for more information on this condition.
Sleep problems
Children with ADHD can be very hyperactive and find it difficult to sleep at night. They may experience irregular sleeping patterns.
Epilepsy
Epilepsy is a condition of the brain that causes seizures (fits). See the Health A-Z topic about Epilepsy for more information on this condition.
Tourette's syndrome
Tourette's syndrome is a condition of the nervous system (the nerves, brain and spinal cord) that causes involuntary movements and sounds. See the Health A-Z topic about Tourette’s syndrome for more information.
Learning difficulties
It is thought that around a third of children with ADHD also have learning difficulties, such as dyslexia (difficulty reading and spelling words). However, it is important to remember that ADHD has no effect on intelligence.
Symptoms in adults
In adults, the symptoms of ADHD are more difficult to define. This is largely due to a lack of research into adults with ADHD.
It is still uncertain whether ADHD can occur in adults without it first appearing during childhood, although it is known that symptoms of ADHD often persist from childhood into the teenage years and adulthood. Any additional problems or conditions experienced by children with ADHD, such as depression or dyslexia, are also likely to carry on into adulthood.
By the age of 25, an estimated 15% of people diagnosed with childhood ADHD still have a full range of symptoms, and 65% still have some symptoms that affect their daily lives.
There is no definitive list of adult ADHD symptoms, and experts agree that simply applying the childhood symptoms to adults would not work. This is because the way in which inattentiveness, hyperactivity and impulsiveness affect adults is very different from the way they affect children.
For example, hyperactivity tends to decrease in adults, while inattentiveness tends to get worse as the pressure of adult life increases. Also, adult symptoms of ADHD tend to be far more subtle than childhood symptoms.
Below is a list of symptoms associated with adult ADHD:
- carelessness and lack of attention to detail
- continually starting new tasks before finishing old ones
- poor organisational skills
- inability to focus or prioritise
- continually losing or misplacing things
- forgetfulness
- restlessness and edginess
- difficulty keeping quiet and speaking out of turn
- blurting responses, and poor social timing when talking to others
- often interrupting others
- mood swings
- irritability and a quick temper
- inability to deal with stress
- extreme impatience
- taking risks in activities, often with little or no regard for personal safety or the safety of others
As with ADHD in children and teenagers, ADHD in adults can appear alongside many related problems or conditions. One of the most common conditions is depression. Other conditions that adults may have alongside ADHD include:
- personality disorders
- bipolar disorder, a condition that affects your moods, which can swing from one extreme to another
- obsessive-compulsive disorder, a condition that causes obsessive thoughts and compulsive behaviour, such as cleaning constantly
Any problems you may have had as a child are likely to persist into adulthood, which can make life extremely difficult. For example, you may have problems:
- finding and keeping employment
- in relationships and social interactions
- with drugs
- with crime
