Diagnosis in children can be only made by a medical professional qualified in paediatric development. This is usually a specialist consultant doctor. Diagnosis is based on observed behaviours. Questionnaires are often used to collate the observations of parents and any other professionals involved the child such as teachers at the school or nursery. There are internationally agreed criteria for diagnosing ADHD and evidence from observations will be used to determine whether this is the correct diagnosis. Diagnosis can be made at any age though there is an expectation that symptoms have been present from before the age of seven. Because ADHD has a strong genetic link it is not uncommon now for parents to be told that they have ADHD when taking their child for diagnosis.
Many children with ADHD experience literacy difficulties and there is evidence to suggest a genetic link between ADHD and dyslexia. There is also good evidence that ADHD children are more likely to experience dyscalculia.
ADHD is also associated with an increased risk of depression, anxiety, self-harm and suicide.