Attention deficit hyperactivity disorder (ADHD) is a heterogeneous disorder characterised by the core symptoms of hyperactivity, impulsivity and inattention, which are judged excessive for the person's age or level of overall development. The diagnosis is made on the basis of observed and reported behavioural symptoms. Two main diagnostic systems 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.
The 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. Therefore, care in differential diagnosis is needed. ADHD may also coexist with other 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. Where there are coexisting conditions, it is important to try to differentiate the level of impairment due to ADHD, because this will guide the treatment plan. In addition, ADHD is under-recognised in some populations, which can mean that a lack of appropriate diagnosis and treatment adversely affects people's quality of life.
The aim of this guideline is to raise awareness of populations at risk and to provide clear advice on managing ADHD.
The guideline covers children under 5 years, children and young people aged 5 to 17 years, and adults aged 18 years or over who are at risk of ADHD or have a diagnosis of ADHD. The guideline covers all primary, secondary and community care settings in which NHS-funded care is provided for people with ADHD.
To find out what NICE has said on topics related to this guideline, see our web page on mental health and behavioural conditions.