What is ADHD?

ADHD is a neurodevelopmental condition — meaning it affects how the brain grows and develops. It typically begins in early childhood and, for many people, continues into adulthood. It is diagnosed more frequently in boys, but is increasingly recognised in girls, who often present differently and are more likely to be missed or diagnosed later.

ADHD is not a single condition — it presents in three main ways:

Predominantly inattentive

Difficulties with focus, organisation, and following through on tasks. Often described as daydreaming, forgetful, or easily distracted. More common in girls and often missed.

Predominantly hyperactive-impulsive

Difficulties sitting still, waiting, and controlling impulses. Often described as restless, impulsive, or always 'on the go'.

Combined presentation

Features of both inattentive and hyperactive-impulsive ADHD. The most commonly diagnosed presentation.

ADHD is caused by differences in brain development and brain chemistry — particularly in the dopamine and noradrenaline systems, which regulate attention, motivation, and impulse control. It runs strongly in families. If a parent has ADHD, there is approximately a 50% chance their child will too.

ADHD often co-exists with other conditions, including autism, anxiety, dyslexia, developmental coordination disorder (DCD), and sleep difficulties. This is why a thorough assessment screens for these alongside ADHD.

Important note

Not every child who is active, distracted, or impulsive has ADHD. These behaviours are normal in young children and in response to stress or change. ADHD is diagnosed when these difficulties are persistent, pervasive (present in more than one setting), and significantly affecting daily life. A proper clinical assessment is the only way to know.

Signs and symptoms to look for

ADHD looks different in every child. Signs tend to show up across more than one setting — at home and at school — and must have been present since early childhood, even if they weren't identified at the time.

Inattentive signs

•       Difficulty sustaining attention on tasks, especially those that are repetitive or not immediately interesting

•       Frequently losing things needed for tasks — pencils, homework, belongings

•       Easily distracted by external things or by their own thoughts

•       Forgetting to do things, even things they intended to do

•       Difficulty following instructions or completing multi-step tasks

•       Appearing not to listen when spoken to directly

•       Making careless mistakes — rushing through work without checking

•       Avoiding tasks that require sustained mental effort

•       Difficulty organising tasks, activities, and time

Hyperactive and impulsive signs

•       Fidgeting, tapping, or squirming — difficulty staying still

•       Leaving their seat when expected to remain seated

•       Running or climbing in inappropriate situations (in younger children)

•       Unable to play or engage in activities quietly

•       Talking excessively

•       Blurting out answers before a question has been finished

•       Difficulty waiting their turn

•       Interrupting or intruding on others' conversations or games

•       Acting without thinking — impulsive decision-making

How ADHD often presents in girls

Girls with ADHD are more likely to have the inattentive presentation and are more likely to mask their difficulties — working hard to appear on top of things, which can mean their ADHD goes unrecognised for years. Signs to watch for include: perfectionism and anxiety about schoolwork; appearing dreamy or 'in their own world'; social difficulties; emotional sensitivity and mood swings; exhaustion from the effort of keeping up; and low self-esteem despite apparent capability.