What is ADHD – Symptoms, Causes and Digital Inclusion for Those Affected

ADHD – Attention Deficit Hyperactivity Disorder – is one of the most common neurodevelopmental disorders. It affects children and adolescents as well as adults and is characterised by persistent inattention, impulsivity and, in many cases, hyperactivity. Estimates suggest that 5–7% of children worldwide and 2–4% of adults are affected – making ADHD far from a niche condition, but a disorder with broad societal relevance.

ADHD is frequently equated with simple restlessness or a lack of discipline – a widespread misconception. The condition has well-established neurological causes: the brains of those affected regulate neurotransmitters such as dopamine differently from people without ADHD. It should be distinguished from the related but separate diagnosis of ADD (Attention Deficit Disorder without hyperactivity), in which motor restlessness is absent but inattention and attentional difficulties are equally pronounced.

For organisations operating digital products, ADHD is relevant for a concrete reason: people with ADHD are among those for whom accessible, low-stimulus and clearly structured websites make a significant difference. WCAG 2.2 addresses cognitive accessibility explicitly – and under the European Accessibility Act (EAA) and the German Accessibility Strengthening Act (BFSG), WCAG AA has been a legal requirement for large parts of the digital market since 28 June 2025.

What is ADHD? Definition, Presentation and Prevalence

ADHD is a neurobiological neurodevelopmental disorder classified in the International Classification of Diseases (ICD-11) as a hyperkinetic disorder. Its presentation is heterogeneous: some individuals primarily show hyperactivity and impulsivity, others are mainly affected by inattention, and others experience all three core symptoms simultaneously. The attentional deficit is the most stable characteristic across the lifespan.

The condition emerges in childhood – symptoms are often first noticed at school, where demands on concentration, self-organisation and impulse control increase. In approximately 60% of cases, ADHD persists into adulthood, frequently with a changed presentation: motor restlessness recedes while inner restlessness, forgetfulness and difficulties working in structured environments become more prominent.

• ✓ Prevalence in children and adolescents: 5–7% worldwide; in Germany, ADHD is among the most frequently diagnosed conditions in childhood and adolescence.
• ✓ Prevalence in adults: 2–4% of adults live with ADHD – many without a formal diagnosis.
• ✓ Gender differences: ADHD is diagnosed significantly more often in boys; in girls the predominantly inattentive presentation is more common, which is less visible and therefore more frequently overlooked.

ADHD Symptoms in Children, Adolescents and Adults

ADHD symptoms change across the lifespan. What presents in childhood as pronounced motor restlessness and impulsive behaviour at school often manifests more subtly in adulthood – as chronic inner restlessness, procrastination or difficulties in relationships and at work. What all age groups share is the attentional deficit: those affected find it harder to regulate attention – either struggling to sustain it or becoming completely absorbed in subjects that captivate them (hyperfocus).

• ✓ Inattention: Frequent careless mistakes, difficulty completing tasks, easy distraction by external stimuli, forgetfulness in daily life.
• ✓ Hyperactivity: Motor restlessness (fidgeting, leaving seat), difficulty sitting still – particularly pronounced in children at school; often experienced as inner restlessness in adults.
• ✓ Impulsivity: Acting without thinking, difficulty waiting, interrupting others in conversation, impulsive decision-making.
• ✓ Impact on areas of life: School and education, work and career, family and relationships, social connections – ADHD impairs all central areas of life when left untreated.
• ✓ Co-occurring conditions: Anxiety disorders, depression, dyslexia and sleep problems occur at above-average rates in people with ADHD.

Causes and Diagnosis: What is Different in the ADHD Brain

ADHD does not have a single cause – it involves a complex interplay of genetic and neurobiological factors. Twin studies show a heritability of around 70–80%, making ADHD one of the most strongly genetically influenced mental health conditions. In the brains of those affected, the neural circuits regulating dopamine and noradrenaline are primarily impaired – neurotransmitters that are critical for attentional control, impulse regulation and working memory.

ADHD is diagnosed clinically by specialist practitioners: child and adolescent psychiatrists, neurologists or clinical psychologists. The process is based on structured interviews, standardised questionnaires, behavioural observations and – in children – reports from school and family. There is no blood test or imaging procedure that can diagnose ADHD alone. Parents play a central role in the diagnostic process for children: their observations from daily life are an essential part of the clinical assessment.

ADHD Treatment: Therapy, Medication and Everyday Strategies

Effective ADHD treatment is multimodal – it combines several approaches tailored to the individual circumstances of those affected. The goal is not to cure the condition but to reduce impairment across key areas of life such as school, work and family, and to build on strengths and competencies.

• 1 Behavioural therapy: The cornerstone of any ADHD treatment – helps those affected develop strategies for self-organisation, impulse control and managing everyday challenges.
• 2 Parent training: Parents learn to respond constructively to ADHD-typical behaviours in their children and to create a supportive structure in daily life.
• 3 School-based support: Reasonable adjustments, structured task-setting and close coordination between school and family reduce the impact of the condition on educational achievement and social participation.
• 4 Medication: Stimulants such as methylphenidate (Ritalin, Concerta) and amphetamines are well-evidenced and a recognised treatment option for moderate to severe ADHD – always in combination with other measures, never as a standalone therapy.
• 5 Everyday strategies: Regular physical activity, consistent daily routines, stimulus reduction in learning and working environments, and digital tools all demonstrably support those affected in daily life.

ADHD and the Web: How Digital Accessibility Helps Those Affected

For people with ADHD, the digital experience is often stressful: stimulus-rich websites with animated banners, confusing navigation, long walls of text without clear headings and competing visual elements quickly overwhelm the attentional system. Those affected lose the thread, abandon tasks or leave pages before reaching their goal.

The measures that help people with ADHD are directly aligned with good accessibility practice: clear heading hierarchies, consistent navigation, sufficient white space, no auto-playing animations and a recognisable focus path. WCAG 2.2 addresses precisely these points – for example criterion 2.2.2 (moving content pausable), 2.4.6 (descriptive headings) and 3.2.3 (consistent navigation).

• ✓ Clear structure: A logical heading hierarchy and consistent navigation help those affected to process content and maintain orientation.
• ✓ Stimulus reduction: No auto-playing videos, no flashing elements, no pop-ups that destroy focus.
• ✓ Focus mode: Draws attention to the currently relevant content and hides distracting page elements.
• ✓ Short, structured texts: Paragraphs of no more than 3–4 sentences, subheadings every 150–200 words and visual anchors make reading considerably easier.

Frequently Asked Questions about ADHD