Home > About ADHD > What is Attention Deficit Hyperactivity Disorder (ADHD)?

ADHD is a neurobiological developmental disorder that begins in childhood and can continue across the lifespan. It is characterised by symptoms of inattention, hyperactivity and impulsivity. Three types of ADHD can be diagnosed through behavioural analysis, as an inattentive type, a hyperactive/impulsive type and a combined type. The type of ADHD diagnosed depends on the most predominate set of symptoms.


Inattentive behaviours can include:

  1. does not seem to hear you when you ask them to do something (needing to ask a number of times to get a response)
  2. not following through on what you ask, despite agreeing to do so (e.g. put your bag away)
  3. easily distracted from a task by noises or own thoughts (hard to keep attention on the task at hand)
  4. daydreaming in class so that important instructions or teachings are missed
  5. not following safety instructions (e.g. “Stop the scooter at the corner”)
  6. losing important belongings (e.g. school jumpers, library books, lunch boxes, travel passes, school permission notes, phones and chargers)
  7. forgetting to bring homework books home
  8. forgetting to do homework or return homework to school
  9. not looking after important belongings (e.g. homework or school photos crushed in school bag, lids left off glue)
  10. starting a task but not completing it, often due to getting distracted or bored
  11. messy and disorganised bedroom (e.g. drawers and doors left open, rotting food in old lunchboxes)
  12. leaving doors and windows unlocked if last to leave home (teenagers)
  13. losing track of time and regularly running late / poor sense of time.

Hyperactive behaviours can include:

  1. running off at school
  2. climbing up furniture, trees, fences in an unsafe manner despite being asked not to do so (preschool, primary school)
  3. not remaining seated in the classroom
  4. constant chatter or talking too loudly and at the wrong times
  5. interrupting other people’s conversations because unable to wait
  6. difficulty getting to bed, staying in bed, or getting to sleep at night
  7. throwing things in the classroom without thinking (e.g. balls) and therefore breaking windows or furniture by accident.

Impulsive behaviours can include:

  1. being disruptive in class, perhaps trying to entertain people
  2. starting an activity without thinking through the consequences
  3. rushing through activities without doing them properly in order to get them done (e.g. homework)
  4. impulsively speaking without realising the comment might be inappropriate
  5. difficulty keeping secrets when asked
  6. difficulty tolerating boredom (opting for stimulating activities)
  7. getting excited about something new then quickly losing interest
  8. difficulty persisting with activities that require commitment and practice unless very interested (e.g. learning an instrument or language, maths practice)
  9. overeating and making poor food choices
  10. smoking or drinking or impulsive sex (in teenage years)
  11. running up bills for excessive phone use or TV/music downloads
  12. careless spending of pocket money or other savings
  13. difficulty resisting the stimulation of social media, internet, TV and gaming
  14. engaging in risky impulsive activities, typically when revved up in the company of friends (e.g. train-surfing, shopping trolley joy-rides, shoplifting minor items).