ADHD and the brain

Brain systems that support planning, selective attention, impulse control, motivation and switching between activities may work less consistently in ADHD. This is not a character flaw. Studies comparing groups of children have identified, on average, later cortical maturation in ADHD, while the overall sequence of development remained broadly similar. These findings describe average differences between groups. Not every person with ADHD shows the same brain features. For this reason, brain imaging cannot currently be used on its own to diagnose ADHD.

Dopamine, noradrenaline and reward

Dopamine and noradrenaline are involved in several interconnected systems that support attention, alertness, motivation and the experience of reward. People with ADHD may find it more difficult to begin and continue tasks that provide little immediate interest or reward. Examples include routine administration, completing forms, working through spreadsheets or finishing the final stages of a longer task. Research does not suggest that dopamine is responsible only for hyperactivity or that noradrenaline is responsible only for inattention. These chemical messengers are involved in several linked systems.

Executive functioning

A person may know what needs to be done but find it difficult to begin at the right time, organise the steps and follow the task through consistently. In everyday life, this may appear as inaccurate time estimates, forgotten steps or postponing tasks. For example, someone may expect a task to take only twenty minutes, begin too late and then find it difficult to move on to the next task. This helps explain why advice such as “just try harder” or “pull yourself together” can be misleading.