What is ADHD?

The three core symptom domains

Inattention

Difficulty sustaining attention, organising tasks, following through, keeping track of belongings or avoiding distraction — beyond what would be expected for age and context.

Hyperactivity

Restlessness or excessive activity. In adults this can feel more like an internal sense of being driven, difficulty sitting through situations or needing constant stimulation.

Impulsivity

Acting, speaking or deciding quickly without enough pause to consider consequences.

Presentations can look different

ADHD can be predominantly inattentive, predominantly hyperactive/impulsive, or combined. The way it looks can also change with age, environment, demands and coping strategies. A person does not need to look “hyperactive” to have ADHD.

Impairment matters

NICE requires symptoms to cause at least moderate psychological, social, educational or occupational impairment and to occur in two or more important settings. That is one reason a good assessment looks at real-life function, not just symptom counts.

ADHD often overlaps with other conditions

A thorough clinician considers alternative explanations and coexisting conditions. Anxiety, depression, sleep problems, autism, learning difficulties, substance use, trauma and physical-health issues may overlap with ADHD or alter how symptoms are experienced.

What ADHD is not

• It is not established by an online quiz alone.
• It is not simply “poor concentration”.
• It is not ruled out because someone performed well at school or university.
• It is not automatically confirmed because stimulant medication feels helpful.

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