ADHD can occur in people of any intellectual ability. However, many people with ADHD also have learning difficulties. They may also have additional problems such as sleep disorders.
Symptoms of ADHD tend to be first noticed at an early age, and may become more noticeable when a child's circumstances change, such as starting school.
Young children are naturally active and easily distracted. However, if these features are excessive for a child's age and general developmental level and affecting their daily life, they may indicate ADHD.
ADHD is the most common behavioural disorder in the UK. It is estimated the condition affects 2-5% of school-aged children and young people.
ADHD can be a lifelong condition, and many children continue to have symptoms as a teenager and adult.
It is estimated that more than 2 out of 3 children diagnosed with ADHD will still have symptoms as teenagers. It is then estimated that 2 out of 3 of these teenagers will show symptoms as adults.
It is uncertain whether ADHD can occur in adults without first appearing in childhood.