Neurobiology of Attention Deficit Hyperactivity Disorder (ADHD) – A Primer

Posted on:March 21, 2019
Last Updated: November 10, 2023
Time to read: 12–14 minutes

ADHD is a neurodevelopmental disorder characterised by symptoms of inattention, impulsivity and locomotor hyperactivity.

The prevalence of ADHD in children and adolescents is estimated to be 5.3% (worldwide) [Polanczyk, 2007] and between 4.4% -5.2% in adults between 18-44 years of age. [Young and Goodman, 2016]

Traditionally thought to be a disorder of childhood and adolescents, there is increasing evidence that the condition is prevalent in adulthood and can lead to significant disability.

ADHD frequently persists into adulthood with up to 60% of children continuing to meet diagnostic criteria during adulthood. [Faraone and Biederman, 2005]

As the child grows, the clinical presentation of ADHD is likely to change with inattention more likely to persist compared to hyperactivity, which tends to diminish with age. [Faraone et al., 2006]

However, some adult patients will only meet symptom criteria for adult ADHD without ever meeting the criteria during childhood. This is possibly indicative of a late-onset variant of ADHD. [Faraone and Biederman, 2016]

In this article, we focus on the neurobiology of ADHD and the different models hypothesised in the genesis of the condition.