What is ADHD?

ADHD is a neurodevelopmental disorder1

Neurodevelopmental disorders are a group of disorders which affect the development of the nervous system, leading to abnormal brain function,1 which may affect emotion, learning ability, self-control and memory. The effects of neurodevelopmental disorders tend to last for a person’s entire lifetime.

The main symptoms of ADHD are:2

  • Inattention e.g. easily distracted, makes careless mistakes, difficulty concentrating.
  • Hyperactivity e.g. feeling restless, having trouble working quietly, talking excessively or interrupting others.
  • Impulsivity e.g. acting inappropriately, such as acting without thinking, interrupting and intruding on others.

Once thought to be a childhood disorder where symptoms reduced as you got older, ADHD is now known to continue into adulthood in around half of people diagnosed in childhood.3-5 Research shows that ADHD affects approximately one in 30 adults aged 18-44 years old, although this varies.6

Some ADHD symptoms appear differently in adults compared with children and young people. This is because ADHD symptoms can change throughout your life. The effects of ADHD can reduce as adults learn to cope with, and overcome, some of their difficulties.7

There is no one test for ADHD so doctors use a variety of methods to diagnose ADHD.8 The screener on this website has 6 questions that can be used to indicate possible ADHD in adults.9


It is important to remember that only a doctor can diagnose ADHD.
If after taking the test you have any concerns, please make an appointment with your doctor.
Please note: This is not a diagnostic test. Only your doctor can diagnose Adult ADHD.


  1. Thapar A, et al. Lancet Psychiatry. 2017 Apr;4(4):339-346.
  2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition. Washington, DC: 2013.
  3. Barkley RA, et al. J Abnorm Psychol 2002; 111: 279-89.
  4. Lara C, et al. Biol Psychiatry 2009; 65: 46-54.
  5. Faraone SV, et al. Psychol Med 2006; 36: 159-65.
  6. Fayyad J, et al. Br J Psychiatry. 2007 May;190:402-9.
  7. Kooij SJ, et al. BMC Psychiatry. 2010 Sep 3;10:67.
  8. National Institute for Health and Care Excellence (NICE). Attention deficit hyperactivity disorder: diagnosis and management: guidance (NG87). March 2018.
  9. Hines JL, King TS, Curry WJ. The adult ADHD self-report scale for screening for adult attention deficit-hyperactivity disorder (ADHD). J Am Board Fam Med. 2012 Nov-Dec;25(6):847-53.