What is ADHD?

Attention deficit hyperactivity disorder, or ADHD, is a neurodevelopmental condition that affects how a person focuses, regulates impulses, and manages activity levels. It is one of the most well-researched conditions in mental health, with clear diagnostic criteria and effective evidence-based treatments.

ADHD usually begins in childhood, though it is not always recognised at that stage. For many adults, the patterns become clearer once life demands grow: at university, in the workplace, or while raising a family. The way ADHD shows up is unique to each person, shaped by personality, environment, and the support they have had along the way.

The condition affects three core areas. Inattention can look like difficulty concentrating, losing track of tasks, or feeling mentally elsewhere. Hyperactivity may show up as restlessness, fidgeting, or a constant sense of being on the go. Impulsivity includes acting or speaking before thinking through the consequences.

These traits affect daily life: school, work, relationships, finances, and self-image. ADHD is not a character flaw or a result of poor effort. It is a difference in how the brain regulates attention and activity. Recognising ADHD is often the first step towards calmer, more confident days ahead.

For a clinical overview, see the NHS guide to ADHD or NICE clinical guidance NG87.