Understanding ADHD

Attention Deficit Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) can affect a person's ability to concentrate, stay organized, control impulses, and manage their activity levels. Everyone experiences ADHD differently. Some people mainly struggle with attention, others with restlessness and impulsive behaviour, while some experience a combination of both.

Clinicians use the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) when assessing ADHD. The DSM-5-TR recognizes three presentations of ADHD: predominantly inattentive, predominantly hyperactive-implulsive, and combined. The DSM-5-TR diagnostic criteria includes nine symptoms of each inattention or hyperactive, with six or more symptoms needed for diagnosis.

Inattention: Diagnostic Criteria DSM-V-TR Definition	What This Means	Example
Difficulty noticing details or making avoidable mistakes	An individual may rush through work, overlook important details or make mistakes because they haven't carefully checked what they're doing.	An individual understands their maths homework but repeatedly misses instructions, skips parts of questions or writes down the wrong numbers because they haven't noticed the details.
Difficulty maintaining attention	An individual may find it hard to stay focused on an activity, especially when it takes a long time or isn't particularly interesting to them.	An individual starts a worksheet but soon begins looking around the room, doodling or thinking about something else before finishing it.
Appearing not to listen when spoken to directly	An individual may seem not to hear or take in what someone is saying, even when the person is speaking directly to them.	A parent explains what needs to be packed for school, but the individual later cannot remember the instructions because their attention drifted during the conversation.
Difficulty following through on instructions or finishing tasks	An individual may begin a task but become distracted, lose track of the steps or leave it unfinished.	An individual is asked to tidy their bedroom. They put away a few items, notice a book they like and start reading it, leaving the rest of the room untidy.
Difficulty organising tasks and activities	Planning, keeping track of steps, managing time and organising belongings may be challenging.	An individual has several school assignments due during the week but struggles to decide what to do first, forgets which materials they need and leaves work until the last minute.
Avoiding tasks that require sustained mental effort	Activities that require prolonged concentration or careful thinking may feel especially difficult to begin or continue.	An individual repeatedly puts off a lengthy reading assignment or asks to do something else whenever they are asked to complete a task that requires sustained concentration.
Frequently losing things needed for activities	An individual may often misplace belongings they need for school, hobbies or everyday tasks.	An individual regularly cannot find their homework folder, pencils, library books or sports equipment, even when they had them earlier that day.
Being easily distracted	An individual's attention may shift quickly to things happening around them or to unrelated thoughts.	While working on homework, an individual stops each time they hear someone talking in another room, notice a noise outside or remember something unrelated.
Being forgetful in everyday activities	An individual may frequently forget ordinary responsibilities or the steps in their daily routine.	An individual regularly forgets to bring home a permission slip, take the items they need for an activity or complete a familiar daily task, even after being reminded.

Hyperactivity and Impulsivity: Diagnostic Criteria DSM-V-TR Definition	What This Means	Example
Frequent fidgeting or squirming	An individual may find it difficult to keep their hands, feet or body still when sitting.	During a classroom lesson, an individual repeatedly taps their feet, twists in their chair, fiddles with objects or changes position.
Leaving their seat when expected to remain seated	An individual may frequently get up during activities when others are expected to stay in their seats.	During a classroom activity, an individual repeatedly stands up or walks around instead of remaining seated with the group.
Running or climbing when it is inappropriate	An individual may have difficulty keeping their movement within the limits of a particular situation.	While waiting in a shop, an individual repeatedly runs between aisles or climbs onto furniture when the situation calls for remaining nearby.
Difficulty playing or participating in activities quietly	An individual may struggle to keep their voice and activity level quiet during activities that require it.	During a quiet classroom activity, an individual frequently makes noises, speaks aloud or becomes noticeably louder than the situation calls for.
Seeming constantly on the go	An individual may appear to have a constant need to move or do something, even when the situation calls for slowing down.	During a family gathering, an individual moves between activities, gets up repeatedly and finds it difficult to settle into a quiet activity for very long.
Talking excessively	An individual may speak much more than the situation calls for or find it difficult to stop talking.	During a group activity, an individual talks at length about their ideas, continues speaking while others are trying to contribute and struggles to notice when the conversation needs to pause.
Answering before a question is finished	An individual may respond before someone has finished asking a question or explaining what they mean.	A teacher asks a question to the class, and an individual calls out an answer before the teacher has finished speaking.
Difficulty waiting their turn	Waiting patiently can be particularly challenging, especially when an individual is excited or eager to participate.	During a board game, an individual repeatedly tries to take their turn early or becomes very impatient while waiting for other players.
Interrupting or intruding on others	An individual may enter conversations or activities before recognising that other people are still speaking or need their own space.	An individual repeatedly interrupts a parent's conversation to share a thought or joins a game already in progress without waiting for an appropriate opportunity.

The combined presentation applies when a person meets the symptom criteria for both inattention and hyperactivity/impulsivity. For example, a child may frequently forget instructions and lose school materials while also fidgeting, interrupting others, and struggling to wait their turn.

These examples are for informational purposes only and are not a checklist for diagnosing ADHD. Every child is different, and a clinician considers the overall pattern of symptoms, the child’s developmental history, and how these symptoms affect everyday life. A comprehensive assessment is needed to determine whether a child meets the diagnostic criteria for ADHD. Learn more about the assessment process for autism and ADHD.