Understanding the official ADHD diagnosis criteria is key to recognising when the condition warrants professional assessment, rather than simply symptoms. At Hively we break down how clinicians apply the criteria (based on the DSM‑5 and Australian-based guidelines) and what those criteria mean in everyday terms for children, teens and adults.
It’s important to note that diagnosis isn’t about labelling; it’s about understanding how attention and regulation work for you so support can be tailored effectively.
What Do We Mean by “Diagnosis Criteria”?
A trained health professional uses diagnostic criteria to decide whether a person meets the definition of Attention‑Deficit/Hyperactivity Disorder (ADHD). These include the number of symptoms, their duration, the settings in which they appear (such as home, school or work), their age of onset, and the extent of functional impact.
In Australia, the criteria align with international standards, primarily the DSM-5 and ICD-11. Clinicians look for symptoms that appear before age 12, affect at least two settings, and reduce the person’s ability to function. The Australian ADHD Professionals Association notes the requirement that symptoms must negatively impact academic, social or occupational performance.
It’s important to differentiate diagnosis criteria from simply noticing symptoms (e.g., forgetfulness, restlessness). Meeting full criteria involves structured thresholds and professional judgement.
Key Components of the ADHD Diagnosis Criteria Explained
See below the major elements that must be considered when diagnosing ADHD in Australia and internationally, and what those elements mean in everyday life.
1. Number of symptoms in each category
- For children and adolescents up to 16 years, the DSM-5 requires at least six symptoms of inattention or hyperactivity-impulsivity.
- For adolescents (17 +) and adults, at least five symptoms are required.
- These symptoms are grouped into two domains: Inattention and Hyperactivity/Impulsivity.
In practice, a clinician will count the number of behaviours from the standard lists you or your child displays regularly, and compare them to these thresholds.
2. Duration and persistence
- Clinicians diagnose ADHD only when symptoms have lasted at least six months.
- They must be inappropriate for the person’s developmental level (i.e., more than just “being a bit distractible”).
It’s not ADHD if you’ve had one bad month or a short-term problem; the behaviours must be stable enough to suggest a pattern, not just a reaction to stress.
3. Onset before a specified age
- Several symptoms must have been present before age 12 (in the DSM-5 criteria).
- In Australian commentary, this is consistently emphasised.
Even if an adult is only diagnosed now, there should be retrospective evidence (school, home life, earlier behaviour) that some of the symptoms were present in childhood.
4. Occurrence in two or more settings
- Clinicians confirm ADHD only when symptoms appear in multiple settings, such as home + study/work; not just in one environment.
If challenges only occur at home but the person functions fine at work, it may not meet the full criteria; specificity to one context may suggest other issues.
5. Functional impairment
- ADHD traits must consistently impact daily functioning across settings, i.e. in social, academic or occupational functioning.
- They cannot be better explained by another disorder (e.g., mood or anxiety disorder).
It’s not about being “a bit more distracted than others”, it’s about those behaviours interfering with how well you study, work or maintain daily life.
6. Differential diagnosis and exclusion of other causes
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The clinician rules out other causes before confirming ADHD. For example: anxiety, depression, sleep disorder or substance use.
For example, if someone is very inattentive purely because of untreated sleep apnoea, the diagnosis of ADHD may not apply; the process must rule that out.
Types of ADHD and How They Relate to ADHD Diagnosis Criteria
According to the DSM-5 and clinical guidelines:
- Predominantly Inattentive Presentation: when most of the symptoms are of inattention (five or more in adults).
- Predominantly Hyperactive-Impulsive Presentation: when most symptoms are hyperactivity/impulsivity.
- Combined Presentation: when both sets of symptoms meet the threshold.
This means that ADHD doesn’t always look the same. Some may mostly struggle with attention and organisation, others with restlessness and impulse control, others have a mix. The “type” helps guide treatment and support planning.
How the ADHD Diagnosis Criteria Guide the Process
- The criteria provide a consistent, evidence-based way for clinicians to make an accurate diagnosis.
- They also highlight that ADHD is a neurodevelopmental condition rather than a behavioural issue.
- In practice, clinicians use the criteria to confirm that a diagnosis is valid when the onset and persistence requirements are met.
Limitations of the ADHD Diagnosis Criteria
- Some people with attention or impulse challenges fall outside the full criteria, yet still need support.
- In addition, the criteria do not specify how symptoms show at every life stage, which means presentation can still vary.
- Finally, these criteria never replace a full clinical assessment, which includes history, interviews and functional evaluation.
Why Understanding ADHD Diagnosis Criteria Matters
- When preparing for an ADHD assessment through Hively, it helps to understand the diagnostic criteria. This gives you clearer expectations around the history we’ll ask about, the settings to consider, and the evidence that supports the process.
- Being told you might have ADHD but not meeting full criteria can feel confusing. Knowing how the criteria work clarifies the reasons behind that decision, such as age of onset, number of settings or degree of impairment.
- For those with an existing diagnosis, the criteria also explain why certain symptoms guide treatment planning, such as organisational strategies for inattention or impulse-control approaches for hyperactive/impulsive traits.
Final Thoughts
Ultimately, the ADHD diagnosis criteria are a structured way for professionals to determine whether someone’s symptoms meet the threshold of the condition — accounting for number of symptoms, duration, age of onset, settings, and impact. While they may seem technical, they matter because they help ensure diagnosis is accurate and appropriate.
At Hively, we work with adults and children to navigate this process: gathering history, assessing across life-domains, and making sense of how the criteria apply to you.
A professional ADHD assessment provides clarity, validation, and a foundation for strategies that improve well-being. If you’re wondering whether your difficulties reflect ADHD (or something else), you’re not alone, and understanding the criteria is a helpful first step.
If you suspect you may have ADHD, book in for an ADHD assessment and we’ll guide you along your journey.
