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ADHD
ADHD is a common neurodevelopmental condition which can affect individuals from childhood into adulthood, impacting various aspects of daily life. It is characterised by difficulties with attention, controlling impulsive behaviours, and managing activity levels.
Overview
Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental condition that typically begins in childhood and can persist through adolescence and adulthood. It is characterised by a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development [PMID:33671239]. These symptoms are generally present across multiple settings, such as at home and school or work, and are not simply due to opposition or a lack of understanding.
ADHD is one of the most common neurodevelopmental conditions diagnosed in children, affecting approximately 5-7% of children globally. While many people associate ADHD with childhood, the condition often continues into adulthood, though symptoms may present differently as individuals age. For example, hyperactivity may become more internalised as a feeling of restlessness rather than overt physical activity. The challenges associated with ADHD can affect academic performance, occupational success, and social relationships [PMID:33261665].
Symptoms & clinical features
The symptoms of ADHD are generally grouped into two main categories: inattention and hyperactivity-impulsivity. A diagnosis usually requires several symptoms from one or both categories to be present for at least six months, and to be disruptive or inappropriate for the individual's developmental level.
Inattentive symptoms include difficulty sustaining attention during tasks or play, frequently making careless mistakes, not seeming to listen when spoken to directly, struggling to follow instructions, poor organisation, avoiding tasks requiring sustained mental effort, often losing items, and being easily distracted. Hyperactivity symptoms often involve fidgeting, difficulty remaining seated, excessive running or climbing in inappropriate situations, difficulty playing quietly, generally being 'on the go', and talking excessively. Impulsivity symptoms include blurting out answers before questions are completed, difficulty waiting their turn, and interrupting others [PMID:33671239]. The specific presentation of ADHD can vary greatly between individuals, with some primarily experiencing inattention, others primarily hyperactivity-impulsivity, and many experiencing a combination of both.
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Affected organs
ADHD primarily affects brain function, particularly areas involved in executive functions such as attention, impulse control, and activity regulation. While not an 'organ disease' in the traditional sense, research suggests differences in brain structure and function, especially in the prefrontal cortex, basal ganglia, and cerebellum, which play key roles in cognitive control and motor activity. These differences are thought to contribute to the characteristic symptoms of ADHD.
Risks & severity
The severity of ADHD symptoms can vary significantly from person to person, ranging from mild to severe. The impact of ADHD can depend on the number and intensity of symptoms, as well as the support systems available to the individual. Challenges can include difficulties in academic or professional settings, strained relationships, and an increased risk for other mental health conditions such as anxiety or depression.
ADHD is typically diagnosed in childhood, often when symptoms become noticeable at school. However, it can also be diagnosed later in life when symptoms that have been present since childhood become more impactful. Family history is a significant risk factor, and numerous genetic and environmental factors are believed to contribute to the development of the condition. ADHD is a lifelong condition, but with appropriate management and support, individuals can learn strategies to manage their symptoms effectively.
Genetic causes
ADHD is considered a complex or polygenic condition, meaning it is influenced by multiple genes acting together, alongside environmental factors. There isn't a single 'ADHD gene' that causes the condition, but rather several genes that contribute to an increased susceptibility.
Genes commonly studied in relation to ADHD include DRD4, SLC6A3, and SNAP25. DRD4 and SLC6A3 are involved in regulating dopamine, a neurotransmitter that plays a crucial role in regulating attention, motivation, and reward within the brain. Variations in these genes may affect how dopamine is processed, potentially influencing ADHD symptoms. SNAP25 is involved in the release of neurotransmitters, and variations here may also impact brain signalling. It is important to remember that these genes are risk factors and not deterministic; an individual might carry these genetic variations and never develop ADHD, or develop it without these specific variants.
Inheritance pattern
ADHD has a polygenic or complex inheritance pattern. This means that multiple genes, each contributing a small effect, interact with environmental factors to influence an individual's likelihood of developing the condition. It is not inherited in a simple Mendelian pattern, like dominant or recessive conditions.
While there is often a strong familial component - individuals with a parent or sibling with ADHD are more likely to have the condition themselves - the risk is not 100%. This is because environmental factors also play a role, and the combination of genetic variants needed to increase susceptibility can differ between family members. Genetic counselling can provide more personalised information regarding familial risks.
Diagnosis & testing
Diagnosing ADHD typically involves a comprehensive assessment by a specialist, such as a paediatrician, psychiatrist, or clinical psychologist. This assessment usually includes gathering information from various sources, including detailed interviews with the individual and their family, school reports, and sometimes standard rating scales or behavioural observation. There are no specific blood tests or imaging scans that can definitively diagnose ADHD.
In the UK, diagnosis often follows a referral from a GP if significant symptoms are present. For children and young people, the process is usually led by child and adolescent mental health services (CAMHS) or a community paediatrician. For adults, an adult ADHD service may be accessed. Genetic testing is not routinely used to diagnose ADHD, as it is a clinical diagnosis based on symptoms and impact on daily life. However, certain genetic tests might be considered in research settings. Referral for genetic testing for neurodevelopmental conditions, where clinically appropriate, falls under the NHS Genomic Medicine Service and may be supported by R-codes such as R408 for developmental disorders.
Management & lifestyle
Managing ADHD typically involves a multi-modal approach tailored to the individual's specific needs. This often includes educational interventions, behavioural therapies, and sometimes medication. Psychoeducation, where individuals and families learn about ADHD, is a key component, helping to understand symptoms and develop coping strategies.
Behavioural interventions might include strategies for improving organisation, time management, and social skills. For some individuals, medication, usually stimulants, can be highly effective in reducing core symptoms of inattention and hyperactivity-impulsivity. Decisions regarding medication are made in consultation with a specialist doctor. Regular reviews and adjustments to the management plan are common as symptoms and life circumstances change. Access to these services is primarily through the NHS, often facilitated by a GP or specialist referral. Genetic counsellors can provide support related to understanding the genetic components of ADHD within a family.
UK care pathway
Within the UK, the care pathway for ADHD typically begins with a GP consultation if concerns are raised. The GP can then refer to specialist services, such as Child and Adolescent Mental Health Services (CAMHS) for children and young people, or adult ADHD services. These specialist services conduct thorough assessments and diagnostic procedures. While ADHD is a clinical diagnosis, the NHS Genomic Medicine Service (GMS) may be involved for individuals with complex neurodevelopmental presentations, potentially involving R-codes like R408 for broader developmental assessments. Genetic counsellors are available to discuss the inheritance patterns and genetic predisposition aspects with affected individuals and their families.
Frequently asked questions
Is ADHD inherited?
Yes, ADHD often runs in families. It is considered a complex condition influenced by multiple genes working together with environmental factors. This means that while a parent with ADHD may pass on a genetic predisposition, it does not guarantee their child will develop the condition.
Can ADHD be cured?
ADHD is a lifelong neurodevelopmental condition, and there is currently no cure. However, with appropriate management strategies, including therapy, educational support, and sometimes medication, individuals with ADHD can learn to manage their symptoms effectively and lead successful lives.
How is ADHD diagnosed in the UK?
In the UK, ADHD is diagnosed through a detailed clinical assessment conducted by a specialist, such as a paediatrician or psychiatrist. This involves gathering information from family, school, and the individual, often using standardised questionnaires, rather than through blood tests or brain scans.
What support is available for adults with ADHD?
Adults with ADHD in the UK can access support through NHS adult ADHD services. This may include psychological therapies, coaching for organisational skills, and medication. A GP can provide a referral to these specialist services.
Are there different types of ADHD?
Yes, specific classifications of ADHD exist that describe the primary presentation. These include 'predominantly inattentive presentation', 'predominantly hyperactive-impulsive presentation', and 'combined presentation'. An individual's presentation can also change over time.
References
- Danielson ML, Claussen AH, Bitsko RH. ADHD Prevalence Among U.S. Children and Adolescents in 2022: Diagnosis, Severity, Co-Occurring Disorders, and Treatment. Journal of clinical child and adolescent psychology : the official journal for the Society of Clinical Child and Adolescent Psychology, American Psychological Association, Division 53. 2024. PMID: 38778436
- Dobrosavljevic M, Larsson H, Cortese S. The diagnosis and treatment of attention-deficit hyperactivity disorder (ADHD) in older adults. Expert review of neurotherapeutics. 2023. PMID: 37725058
- Kooij JJS, Bijlenga D, Salerno L. Updated European Consensus Statement on diagnosis and treatment of adult ADHD. European psychiatry : the journal of the Association of European Psychiatrists. 2019. PMID: 30453134
- Custodio RJP, Hengstler JG, Cheong JH. Adult ADHD: it is old and new at the same time - what is it? Reviews in the neurosciences. 2024. PMID: 37813870
- Sapkale B, Sawal A. Attention Deficit Hyperactivity Disorder (ADHD) Causes and Diagnosis in Adults: A Review. Cureus. 2023. PMID: 38130507
- Nussbaum NL. ADHD and female specific concerns: a review of the literature and clinical implications. Journal of attention disorders. 2012. PMID: 21976033
- Choi WS, Woo YS, Wang SM. The prevalence of psychiatric comorbidities in adult ADHD compared with non-ADHD populations: A systematic literature review. PloS one. 2022. PMID: 36331985
- S Alamri A. Genetic diversity of Attention-Deficit/Hyperactivity Disorder. Pakistan journal of biological sciences : PJBS. 2021. PMID: 34486359