How common is ADHD in adults?
ADHD affects around 3 to 4 in every 100 adults and is more common where a sibling or
ADHD affects about 3 to 4 in every 100 adults. It is more common in people who have a sibling or close family member with ADHD, epilepsy, neurodevelopmental conditions, mental illnesses, or a history of alcohol or drug misuse, or an acquired brain injury.