Attention Deficit Hyperactivity Disorder (ADHD)

Definition | Aetiology | Risk Factors | Clinical Presentation | Investigations | Management | When to Refer | References

Definition

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterised by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development. ADHD can affect children, adolescents, and adults, and it can have significant impacts on academic, occupational, and social functioning.

Aetiology

The exact cause of ADHD is not fully understood, but it is believed to result from a combination of genetic, biological, and environmental factors:

• Genetic Factors: ADHD tends to run in families, suggesting a strong genetic component. Children with a parent or sibling with ADHD are more likely to develop the condition.
• Neurobiological Factors: Differences in brain structure and function, particularly in areas involved in attention and executive function (e.g., the prefrontal cortex), are observed in individuals with ADHD. Dysregulation of neurotransmitters such as dopamine and norepinephrine is also implicated.
• Environmental Factors: Prenatal exposure to alcohol, tobacco, or drugs, low birth weight, and exposure to lead are associated with an increased risk of developing ADHD.
• Psychosocial Factors: While not direct causes, factors such as family stress, poverty, and early adversity can exacerbate ADHD symptoms or impact how the disorder manifests.

Risk Factors

Several factors increase the likelihood of developing ADHD:

• Family History: A family history of ADHD, learning disabilities, or other neurodevelopmental disorders increases the risk.
• Gender: ADHD is more commonly diagnosed in males than females, although it is increasingly recognised in females, who may present with less obvious symptoms.
• Premature Birth: Children born prematurely or with a low birth weight are at higher risk.
• Maternal Health: Maternal smoking, alcohol use, or drug use during pregnancy can increase the risk of ADHD in children.
• Exposure to Environmental Toxins: Exposure to lead or other environmental toxins at a young age is associated with a higher risk of developing ADHD.

Clinical Presentation

ADHD presents with a variety of symptoms that can be categorised into two main domains: inattention and hyperactivity/impulsivity. The severity and combination of symptoms can vary widely:

Inattention

• Difficulty Sustaining Attention: Trouble maintaining focus on tasks or play activities, especially those that are tedious or time-consuming.
• Careless Mistakes: Making frequent errors in schoolwork, work, or other activities due to inattention to details.
• Avoidance of Tasks: Avoidance or reluctance to engage in tasks that require sustained mental effort, such as homework or lengthy assignments.
• Disorganisation: Difficulty managing tasks, keeping track of belongings, or maintaining an organised approach to activities.
• Forgetfulness: Frequently forgetting daily tasks, appointments, or obligations.
• Difficulty Listening: Often seems not to listen when spoken to directly, even without an obvious distraction.
• Frequent Shifting: Difficulty following through on instructions and shifting from one unfinished task to another.

Hyperactivity and Impulsivity

• Restlessness: Fidgeting, tapping hands or feet, or squirming in seat, often described as being "on the go" or "driven by a motor."
• Inability to Stay Seated: Difficulty remaining seated in situations where it is expected, such as in the classroom or at the dinner table.
• Excessive Talking: Talking excessively, often interrupting others or blurting out answers before questions have been completed.
• Difficulty Waiting: Trouble waiting for one's turn, such as in conversations, games, or queueing.
• Impulsivity: Acting without thinking, such as making hasty decisions, interrupting others, or engaging in risky behaviours without considering consequences.
• Climbing or Running Inappropriately: Engaging in physical activity at inappropriate times or places, especially in children.

Investigations

The diagnosis of ADHD is primarily clinical, based on a detailed history, observation, and assessment of symptoms. There are no specific laboratory tests for ADHD, but additional assessments may include:

• Clinical Interview: A thorough interview with the patient (and parents or carers if the patient is a child) to gather detailed information about the onset, duration, and impact of symptoms on daily functioning.
• Behavioural Assessments: Standardised behavioural checklists and questionnaires, such as the Conners' Rating Scales or the ADHD Rating Scale, may be used to evaluate the severity of symptoms across different settings.
• Educational Assessment: Collaboration with teachers and school staff to gather information about academic performance and behaviour in the classroom.
• Neuropsychological Testing: May be conducted to assess cognitive function, attention, memory, and executive function, particularly if there is a concern about learning disabilities.
• Medical Evaluation: A physical examination and review of medical history to rule out other conditions that could mimic ADHD symptoms, such as thyroid disorders, sleep disorders, or vision/hearing impairments.

Management

The management of ADHD involves a combination of behavioural interventions, pharmacotherapy, and educational support, tailored to the individual’s needs:

Behavioural Interventions

• Parent Training: Training programmes to help parents manage their child's behaviour, set clear expectations, and use positive reinforcement effectively.
• Behavioural Therapy: Focuses on developing coping strategies, improving organisational skills, and addressing specific behaviours associated with ADHD.
• Social Skills Training: Helps individuals with ADHD develop better social interactions, communication skills, and relationships.
• Cognitive Behavioural Therapy (CBT): May be used to help older children, adolescents, and adults manage symptoms, particularly around time management, organisation, and self-regulation.
• Environmental Modifications: Adjusting the learning or working environment to reduce distractions and support the individual’s needs, such as seating arrangements, the use of planners, or providing additional time for tasks.

Pharmacotherapy

• Stimulant Medications: The most commonly prescribed medications for ADHD, such as methylphenidate.
• Monitoring and Adjustment: Regular follow-up to monitor the effectiveness of medication, adjust dosages, and manage any side effects or concerns.

When to Refer

Referral to a specialist, such as a paediatrician, psychiatrist, or psychologist, may be necessary in the following situations:

• Severe or complex ADHD symptoms that do not respond to initial behavioural interventions or pharmacotherapy.
• Presence of co-occurring mental health conditions, such as anxiety disorders, depression, or learning disabilities.
• Uncertainty about the diagnosis, especially if other neurodevelopmental disorders or medical conditions are suspected.
• Need for specialised assessments, such as neuropsychological testing or intensive behavioural therapy.
• Significant impairment in daily functioning, including difficulties at school, work, or in social relationships, that require more intensive intervention.

References

1. NHS (2024) Attention Deficit Hyperactivity Disorder (ADHD). Available at: https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/ (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Attention Deficit Hyperactivity Disorder: Diagnosis and Management. Available at: https://www.nice.org.uk/guidance/ng87 (Accessed: 26 August 2024).
3. British Medical Journal (2024) Attention Deficit Hyperactivity Disorder (ADHD): Clinical Review. Available at: https://www.bmj.com/content/350/bmj.h2506 (Accessed: 26 August 2024).

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