Attention deficit hyperactivity disorder (ADHD) is a
neurodevelopmental disorder characterised by excessive amounts of
inattention, hyperactivity, and
impulsivity that are pervasive, impairing in multiple contexts, and otherwise
age-inappropriate
Age appropriateness refers to people behaving as predicted by their perspective timetable of development. The perspective timetable is embedded throughout people's social life, primarily based on socially-agreed age expectations and age norms. Fo ...
.
ADHD symptoms arise from
executive dysfunction,
and
emotional dysregulation is often considered a core symptom.
In children, problems paying attention may result in poor
school performance. ADHD is associated with other neurodevelopmental and
mental disorder
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
s as well as some non-psychiatric disorders, which can cause additional impairment, especially in modern society. Although people with ADHD struggle to focus on tasks they are not particularly interested in completing, they are often able to maintain an unusually prolonged and intense level of attention for tasks they do find interesting or rewarding; this is known as
hyperfocus.
The precise causes of ADHD are unknown in the majority of cases.
[ Genetic factors play an important role; ADHD tends to run in families and has a heritability rate of 74%. Toxins and infections during pregnancy and brain damage may be environmental risks.
It affects about 5–7% of children when diagnosed via the DSM-IV criteria, and 1–2% when diagnosed via the ]ICD-10
ICD-10 is the 10th revision of the Internation