Attention deficit hyperactivity disorder

What is ADHD, or attention deficit hyperactivity disorder?

Adults with attention deficit hyperactivity disorder (ADHD) may experience inattention, hyperactivity or impulsivity. Symptoms interfere with daily functioning and may affect emotional and behavioral regulation, social relationships, study or work, and self-esteem.

ADHD is a chronic neurodevelopmental disorder that may not be diagnosed until adulthood, although symptoms begin in childhood. Hyperactivity may decrease with age; restlessness, impulsive behavior and difficulty concentrating may continue into adulthood, but their severity and impact vary between individuals.

ADHD treatment is individualized according to age, symptoms and difficulties in daily life. It may include medication, psychological and behavioral interventions. Parent training in behavior management is particularly important for young children; for adults, psychological support may include cognitive-behavioral therapy (CBT) adapted for ADHD. Anxiety disorders, depression or substance use disorders may coexist with ADHD.

Timely assessment and appropriate treatment may help a person manage symptoms and improve daily functioning; coexisting conditions require their own assessment and appropriate support.

Main signs of ADHD

The presentation and severity of symptoms may change with age. Hyperactivity is often more noticeable in young children; as school and social demands increase, difficulties with inattention may become more apparent. Symptoms may interfere with learning, work and relationships with peers, particularly when organization, sustained attention and behavioral regulation are needed.

Predominantly inattentive ADHD

In this presentation, difficulty sustaining attention, easy distraction, forgetfulness and difficulty organizing or finishing tasks predominate. Hyperactivity and impulsivity are not the main features of this presentation.

Predominantly hyperactive-impulsive ADHD

Restlessness is noticeable, for example during play or learning that requires following rules. A person may have difficulty sitting quietly, fidget or move their limbs, run or jump in inappropriate situations, have difficulty keeping quiet, or interrupt others. Hyperactivity often occurs with impulsivity, leading to actions without considering their consequences in advance.

Combined ADHD includes both inattentive and hyperactive-impulsive symptoms.

Signs of inattention include:

• Getting distracted easily
• Forgetfulness
• Difficulty listening
• Difficulty completing tasks that require sustained attention
• Difficulty organizing
• Difficulty managing time
• Difficulty concentrating on one task
• Difficulty finishing tasks or following instructions
• Difficulty planning
• Frequent careless mistakes
• Frequently losing small items

Signs of hyperactivity include:

• Difficulty remaining still
• Difficulty waiting for a turn
• Difficulty playing or doing an activity quietly
• Answering before a question is finished
• Restless movements of the hands or feet
• Excessive talking
• Being constantly on the move
• Difficulty sitting still, for example squirming in a chair

Symptoms interfere with functioning in at least two usual settings, for example at home and at school.

Causes of ADHD

Environmental factors

The exact causes of ADHD are not fully understood; researchers are studying the combined influence of genetic and environmental factors. Possible factors associated with ADHD risk include:

• Exposure to lead during pregnancy or early childhood
• Alcohol and tobacco use during pregnancy
• Complications during pregnancy and delivery — factors associated with risk that do not, by themselves, determine whether ADHD develops

Genetic factors play an important role: ADHD occurs more often within families. Genetic predisposition increases risk but does not mean that another family member will necessarily have ADHD.

Neurobiological factors

Researchers are studying differences in brain development and functioning associated with ADHD, including processes involved in attention and behavioral regulation. This does not mean that one specific brain region or a ‘chemical imbalance’ explains every person's symptoms.

When should you see a specialist?

ADHD may often be mistaken for a personality trait or solely a result of upbringing. If symptoms interfere with learning, work, relationships or everyday activities, specialist assessment is important. Support may include developing organizational, emotional and behavioral regulation skills and making necessary changes to the environment. Difficulties and support needs vary between individuals; deterioration in quality of life or harmful behavior is not inevitable.

With age, some ADHD signs may become less noticeable, for example hyperactivity. However, inattention, restlessness or impulsivity may still interfere with daily life. Anxiety disorders, depression and other conditions may coexist with ADHD; assessing them is also important.

Many people have experienced ADHD-like symptoms at some point in life. If you feel that the symptoms described above have persistently disrupted your life and emotional balance since childhood, see a specialist to distinguish ADHD from other conditions, for example sleep problems, anxiety or depression. Assessment includes childhood history, symptoms in different settings and their impact on daily functioning.

Other mental health or neurodevelopmental conditions may coexist with ADHD:

In children:

• Oppositional defiant disorder (ODD), characterized by a pattern of frequent irritability, arguing or defiant behavior
• Conduct disorder, characterized by antisocial or unlawful actions such as fighting, theft, vandalism or cruelty toward people and animals
• Learning disorders

In children, adolescents and adults:

• Autism spectrum disorder
• Tics and Tourette syndrome
• Difficulties with reading, writing or communication may occur
• Substance use disorders
• Anxiety disorders
• Mood disorders

How is ADHD treated?

There is no single laboratory test for ADHD. Diagnosis requires a full clinical assessment by a specialist experienced in ADHD assessment: childhood and developmental history, symptoms in different settings, their impact on daily functioning, and assessment of other possible explanations and coexisting conditions. Questionnaires help with assessment, but their results alone are insufficient for a diagnosis.

Cognitive-behavioral therapy (CBT) helps people develop organizational and emotional regulation skills, identify potentially harmful or unhealthy behaviors and replace them.

Psychoeducation and support programs — for parents, teachers and people with ADHD.

A structured daily routine — developing organizational skills and order.

Medication

Medication may help reduce ADHD symptoms; the specific medicine is chosen individually and requires monitoring of its effects, side effects and other health conditions.

See also

→ ADHD diagnosis and treatment

→ Cognitive-behavioral therapy for ADHD

Related topics: Anxiety disorder · Depression · Psychiatrist consultation

Source: NIMH — Attention deficit hyperactivity disorder (ADHD).

Source: Faraone SV, Larsson H. Genetics of attention deficit hyperactivity disorder. Mol Psychiatry. 2019;24(4):562–575. doi:10.1038/s41380-018-0070-0

Additional sources: NICE NG87 · CDC — ADHD · WHO — ADHD interventions (2023)

Historical prevalence references

1. Polanczyk G, de Lima MS, Horta BL, Biederman J, Rohde LA. The worldwide prevalence of ADHD: a systematic review and metaregression analysis. Am J Psychiatry. 2007;164(6):942–948. doi:10.1176/ajp.2007.164.6.942

2. Simon V, Czobor P, Bálint S, Mészáros A, Bitter I. Prevalence and correlates of adult attention-deficit hyperactivity disorder: meta-analysis. Br J Psychiatry. 2009;194(3):204–211. doi:10.1192/bjp.bp.107.048827