attention deficit hyperactivity disorder

Last edited 03/2022 and last reviewed 09/2022

Attention deficit hyperactivity disorder (ADHD) is a heterogeneous behavioural syndrome characterised by the core symptoms of:

• hyperactivity
• impulsivity
• inattention
  
  
• while these symptoms tend to cluster together, some people are predominantly hyperactive and impulsive, while others are principally inattentive
  
  
• two main diagnostic criteria are in current use
  • the International Classification of Mental and Behavioural Disorders 10th revision (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5)
    • both systems require that symptoms are present in several settings such as school/work, home life and leisure activities
    • symptoms should be evident in early life, if only in retrospect; for ICD-10, by age 7 years and for DSM-5, by age 12 years
    • ADHD may persist into adult life
  • prevalence rates for ICD-10 (identifying hyperkinetic disorder) are 1 to 2% in childhood. Under the previous, less stringent DSM-IV criteria, childhood prevalence rates were 3 to 9% and these may increase under the new DSM-5 criteria
    
    
• causes of ADHD are not fully understood but a number of risk factors are associated with the condition
  • genetic factors can have an influence, with family members frequently affected
  • the diagnosis of ADHD in older family members such as parents may have previously been missed and should be considered
• both the ICD-10 and DSM-5 require the presence of functional impairment due to symptoms of ADHD, with the symptoms adversely affecting psychological, social and/or educational/ occupational functioning
  • the impact of ADHD may vary considerably in its severity, which is best judged by considering the level of impairment, pervasiveness, and familial and social context
    • for some people, symptoms may be limited to certain settings and cause minimal impairment in a limited number of domains (for example, ability to complete schoolwork, work tasks, avoiding common hazards and forming positive interpersonal relationships)
    • in other people, multiple symptom areas (hyperactivity, inattention and impulsivity) are present in multiple settings, and this causes significant impairment across multiple domains
    • symptoms and impact can also change over time. For some people, symptoms and impairment may be reduced through environmental modifications, such as a modified school curriculum or choice of employment
• symptoms of ADHD can overlap with those of other related disorders
  • common coexisting conditions in children include disorders of mood, conduct, learning, motor control, language and communication, and anxiety disorders; in adults, they include personality disorders, bipolar disorder, obsessive-compulsive disorder and substance misuse

Drug treatment for children and young people with ADHD should always form part of a comprehensive treatment plan that includes psychological, behavioural and educational advice and interventions (1). Medication for ADHD should only be prescribed after expert advice:

• when a decision has been made to treat children or young people with ADHD with drugs, healthcare professionals:
  • methylphenidate (either short or long acting) should be offered as the first line pharmacological treatment for children aged 5 years and over and young people with ADHD
    
    
  • consider switching to lisdexamfetamine for children aged 5 years and over and young people who have had a 6-week trial of methylphenidate at an adequate dose and not derived enough benefit in terms of reduced ADHD symptoms and associated impairment
    
    
  • dexamfetamine should be considered for children aged 5 years and over and young people whose ADHD symptoms are responding to lisdexamfetamine but who cannot tolerate the longer effect profile
    
    
  • atomoxetine or guanfacine should be offered to children aged 5 years and over and young people if:
    • they cannot tolerate methylphenidate or lisdexamfetamine or
    • their symptoms have not responded to separate 6-week trials of lisdexamfetamine and methylphenidate, having considered alternative preparations and adequate dose

Drug treatment for adults with ADHD should always form part of a comprehensive treatment programme that addresses psychological, behavioural and educational or occupational needs

• following a decision to start drug treatment in adults with ADHD, lisdexamfetamine or methylphenidate are options as first-line pharmacological treatment

A systematic review (2) found:

• very low-certainty evidence that extended-release methylphenidate compared to placebo improved ADHD symptoms (small-to moderate effects) measured on rating scales reported by participants, investigators, and peers such as family members
  • methylphenidate had no effect on 'days missed at work' or serious adverse events, the effect on quality of life was small, and it increased the risk of several
    adverse effects

Reference:

• (1) NICE (March 2018).Attention defificit hyperactivity disorder: diagnosis and management
• (2) Boesen K et al. Extended-release methylphenidate for attention deficit hyperactivity disorder (ADHD) in adults. Cochrane Database of Systematic Reviews 2022, Issue 2. Art. No.: CD012857. DOI: 10.1002/14651858.CD012857