Introduction
Attention-deficit/hyperactivity disorder (ADHD) presents a significant challenge to healthcare systems globally because of its prevalence and associated economic burden (Schein et al., 2022). The costs of ADHD resulting from educational underachievement, lost productivity, healthcare expenditure and even contact with criminal justice services, are substantial and appear to be rising (Chhibber et al., 2021). This growing economic impact is exacerbated by a shortage of trained diagnosticians, both internationally and specifically in Aotearoa New Zealand, which contributes to delays and inconsistent diagnostic practices (Skirrow et al., 2023). In response to these challenges, there has been increasing demand for quicker, easier access to ADHD treatments as well as corresponding concerns that this may lead to compromises in assessment quality (Matheiken et al., 2024).
This study aimed to address these issues by identifying minimum practice standards for ADHD diagnosis grounded in the most recent international consensus statements. By synthesising guidelines from various global perspectives, this study sought to establish a framework for ensuring that diagnostic practices are accessible and also rigorous, thorough and culturally sensitive. The goal was to provide healthcare professionals and the clients they serve with a set of standards that maintain high diagnostic quality while balancing the increasing demand for timely ADHD assessments.
Methods
Ethical Approval
This study involved no human or animal participants and therefore was not subject to formal ethical approval.
Identification of Clinical Practice Guidelines
The recent Australian ADHD Professionals Association (AADPA) (2022) guidelines for ADHD reviewed the 25 professional guidelines published between 2001 and 2018; therefore, we chose to focus specifically on guidelines published between 2018 and 2024. Following the same methodology described in the AADPA (2022) guidelines, an Internet search was conducted to identify evidence-based guidelines using the Google ‘Advanced Search’ function, because many guidelines are not published in journals and do not feature in common academic search tools such as Medline or PsychInfo. We set the English language filter and the search string was: (Attention Deficit Hyperactivity Disorder OR attention deficit OR ((hyperactivity OR hyperkinetic) AND disorder) OR ADHD) AND (guideline OR evidence OR systematic). The results were hand-searched for relevance, identifying six consensus practice guidelines for ADHD diagnosis. A subsequent hand-search of the references of recently published (2024) guidelines identified a further four consensus statements. One of these additional guidelines focused solely on practice with individuals with substance abuse and comorbid ADHD (Crunelle et al., 2018). Another represented an evidence-based review of the effectiveness of diagnostic procedures (e.g. electroencephalogram) in differentiating ADHD but did not include wider recommendations for assessment (Kemper et al., 2018). After exclusion of these two guidelines, eight consensus practice guidelines for the diagnosis of ADHD were included in this review, all of which were published between 2018 and 2024. Several of these guidelines represented updates of those previously reviewed by AADPA (2022). Details of the guidelines selected for review are included in Table 1.
Analysis
This study employed content analysis as the primary qualitative methodology, following the approach outlined by Hsieh and Shannon (2005). Content analysis is a flexible and systematic technique used to analyse qualitative data, and focuses on identifying patterns and themes in textual content. It involves the process of coding text into manageable categories based on the presence of specific words, phrases or concepts.
The analysis in this study adopted a typical three-step process, as per Hsieh and Shannon’s (2005) guidelines:
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Preparation of data: Textual data (such as guidelines, interviews or documents) were carefully read and reviewed to gain a general understanding of the content.
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Initial coding: Key phrases or sections of text were identified and labelled with codes. These codes represented significant concepts or ideas that emerged from the data.
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Theme identification: The codes were grouped into broader categories or themes that reflected common ideas or patterns across the data. These themes were then analysed to draw conclusions relevant to the research objectives.
This approach is less formal and more quantitative in nature than more in-depth approaches such as reflexive thematic analysis (e.g. Braun & Clarke, 2006), as it focuses on identifying significant themes rather than engaging in in-depth iterative coding and reflexivity. It allows for a structured yet accessible method of extracting meaningful insights from qualitative data, and is suitable for studies aiming to summarise key patterns and themes efficiently. Sections of text were coded as either representing a ‘minimum standard’ (stated by the guidelines to be required for a reliable diagnosis) or a ‘best practice standard’ (stated by the guidelines to be desirable for a good quality assessment, without being necessary for diagnosis). After the data were manually coded, the validity of these themes were checked by undertaking secondary analyses using two independent large-language model AI platforms (Google NotebookLM and ChatGPT 4.0). Both of these secondary analyses confirmed the validity of the initial identified themes.
Results
Core Themes: Minimum Practice Standards
Five core elements were explicitly mentioned across multiple guidelines as being expected standards for diagnostic assessments for ADHD. These themes are detailed below and presented in Table 2, with specific quotations from the guidelines to illustrate each theme.
Diagnosis by a qualified specialist. Six of the eight guidelines made explicit reference to the qualifications of the professional making the diagnosis. Many of these directly specified that the diagnosis should be made by a specialist with appropriate training, such as a psychiatrist, paediatrician, psychologist or other appropriately qualified healthcare professional.
Clinicians conducting diagnostic assessments should be:
- appropriately registered…
- adequately trained in diagnostic assessment using the Diagnostic and Statistical Manual of Mental Disorders (DSM) and/or International Classification of Diseases (ICD)
- experienced with conducting clinical interviews, administering and interpreting standardised rating scales, and assessment of functional impairment
- experienced in ADHD diagnostic assessment or undergoing ADHD-specific supervision with an experienced clinician. (AADPA Guideline, 2022, S2.1.1)
A diagnosis of ADHD should only be made by a specialist psychiatrist, paediatrician or other appropriately qualified healthcare professional with training and expertise in the diagnosis of ADHD. (NICE Guideline NG87, 2018, S1.3)
The most commonly listed healthcare professions considered able to diagnose were psychiatrists (listed in six of eight guidelines), followed by psychologists and paediatricians (four guidelines), general practitioners (three guidelines), neurologists (two guidelines), nurses (one guideline) and social workers (one guideline). The highest consensus was that psychiatrists, psychologists and paediatricians would most usually be central to diagnostic services; however, the emphasis was generally on the quality of the diagnostic process rather than the clinician themselves.
Comprehensive assessment. Five of the eight guidelines explicitly stated that the assessment must be extremely thorough, and encompass a clinical and psychosocial evaluation, developmental history, mental health history, observer reports, mental state assessment and medical assessment to exclude other potential causes of symptoms.
An ADHD diagnosis requires an extensive evaluation, and a considerable amount of time is put into gathering the patient’s medical and social history. (WVACC, 2024, p.26)
It is important that the clinician does not rely solely on diagnostic tools and questionnaires but takes the time to obtain a full mental health and developmental history, obtains corroboration and utilises their clinical skills to make an objective assessment of the patient… (RCPS, 2023, S9.7.8)
Both the AADPA (2022, S2.1.4) and NICE (2018, S1.3.2) guidelines contained the following identical statement relating to the role of rating scales and observational data.
A diagnosis of ADHD should not be made solely on the basis of rating scale or observational data.
Explicit reference to DSM or ICD criteria. Seven of the eight guidelines explicitly stated that assessors should ensure that they adhered closely to the diagnostic criteria defined in either the DSM-5 or ICD-11 in making their diagnosis.
To make a diagnosis of ADHD, the PCC [primary care clinician] should determine that DSM-5 criteria have been met… (AAP, 2019, p.5)
For a diagnosis of ADHD, symptoms of hyperactivity/impulsivity and/or inattention should: meet the diagnostic criteria in DSM-5 or ICD-11. (NICE, 2018, 1.3.3)
Evidence of impairment in multiple settings. Six of the eight guidelines explicitly stated that diagnosticians need to have good evidence that symptom-related impairment is evident in more than one setting, corroborated by others (e.g. parents, teachers), reflecting diagnostic criteria such as DSM 5.
Observations from more than one setting and reporter (e.g. a teacher, in the case of children) should be used to confirm if symptoms, function and participation difficulties occur in more than one setting. (AADPA, 2022, S2.1.5)
Both systems [ICD-10 and DSM-5] require that symptoms are present in several settings such as school/work, home life and leisure activities. (NICE, 2018, p.57)
Clear consideration of differential diagnoses. Further to the concept of comprehensive assessment, six of the eight guidelines explicitly stated that alternative diagnoses should first be ruled out or otherwise accounted for. Examples mentioned included hearing or vision problems, thyroid disorders, anaemia, medication side effects and other neurodevelopmental or mental health conditions (including alcohol and drug use).
Several medical disorders can be present and have symptoms and signs similar to those of ADHD. For example, sleep disorders (Baddam et al., 2021), hearing or vision impairment, thyroid disease (American Psychiatric Association, 2013) and anaemia (Konofal, Lecendreux, Arnulf, & Mouren, 2004) (S2.2)…Those working in public and mental health settings should be aware of the high co-occurrence of substance use disorders in those with ADHD. Clinicians treating ADHD in these settings should routinely screen for problematic substance use or substance use disorders using best-practice screening questionnaires for substance use disorders. (AADPA, 2022, S6.3.1)
In the evaluation of a child or adolescent for ADHD, the PCC should include a process to at least screen for comorbid conditions, including emotional or behavioral conditions (eg, anxiety, depression, oppositional defiant disorder, conduct disorders, substance use), developmental conditions (eg, learning and language disorders, autism spectrum disorders), and physical conditions (eg, tics, sleep apnoea). (AAP, 2019, p.9)
Elements of a ‘Best Practice’ Approach
In addition to the ‘minimum standards’ recommended across the eight guideline documents, a number of additional, enhanced approaches were included in several guidelines and could be considered a ‘best practice’ approach to ADHD diagnosis. These themes are summarised in Table 3.
Systematic approach to screening for comorbidities/coexisting conditions. Six of the eight guidelines explicitly recommended a systematic approach to screening for common co-occurring conditions, such as anxiety, depression, learning disorders and autism spectrum disorders, in developing a comprehensive treatment plan.
There are high rates of comorbidity with other mental health conditions and ADHD, in addition to comorbidity with other neurodevelopmental disorders. There is also symptom overlap within neurodevelopmental disorders. Therefore, assessment of ADHD needs to be part of a generic mental health assessment and with reference to other neurodevelopmental disorders to prevent misdiagnosis. (RCPS, 2023, p.7)
As previously mentioned, the prevalence of comorbidities (e.g., anxiety, mood disorders, learning challenges) in patients with ADHD is high, with more than 50% of patients having a comorbid disorder and one in seven patients having three or more (Mattingly et al., 2021). There can be a significant amount of symptoms that overlap between ADHD and other disorders, and the guidelines recommend that clinicians should consistently screen for comorbid conditions when evaluating a patient for ADHD per the recommendations of the expert panel and all reputable ADHD guidelines. (WVACC, 2024, p.61)
Several guidelines suggested cognitive/neuropsychological assessment was likely to be extremely beneficial as part of a wider assessment of ADHD and its associated conditions, particularly in planning further treatment; however, none concluded that it was a necessary pre-requisite for diagnosis.
Cultural sensitivity. Five of the eight guidelines mentioned the importance of culture in the assessment of ADHD, particularly when working with Indigenous peoples or other minority groups. The recommendations included understanding the cultural context of symptoms, employing a strengths-based approach and using cultural and language interpreters where appropriate.
Ethnic, gender and cultural issues may shape the perception and beliefs about ADHD and its treatment. For example, some cultures may have lower acceptance and higher stigma associated with ADHD. (CADRA, 2020, p.44)
Issues of culture were discussed most extensively in the AADPA guidelines, which were also the only guidelines to specifically mention Indigenous cultures.
Some cultures view mental health as a holistic concept beyond the notion of symptoms and functional impairment. This is the case for Aboriginal and Torres Strait Islander peoples, for whom mental health interconnects with numerous domains including spiritual, environment, country, community, cultural, political, social emotional and physical health. (AADPA, 2022, S6.2)
Patient-centred and/or family-centred approaches. Following from a culturally sensitive approach, four guidelines made explicit reference to a person-centred approach that actively involved individual and their family in the assessment process, tailoring the approach (and information) to their needs and preferences.
Best-practice principles include individualized plans developed in accordance with principles of co-production, where people with ADHD, families and carers are at the centre of decision-making about all aspects of their healthcare. (AADPA, 2022, p.61)
It is important to incorporate a patient-/family-centered approach to ADHD treatment by considering individual/family treatment preferences. (CADDRA, 2020, p.41)
A multidisciplinary approach. As noted above, the majority of the guidelines stressed the importance of gathering information about behaviour across settings. For a comprehensive assessment, many recommended including seeking (multiple) third party reports, school records and previous health assessments, as well as working across disciplines, with five explicitly mentioning multi-disciplinary approaches to assessment.
Care integration and coordination ADHD treatment and support requires a multimodal, multidisciplinary and multi-agency approach, particularly when there are co-occurring conditions that significantly impact on a person’s functioning and quality of life. (AADPA 2022, p.95)
Mental health services for children, young people and adults, and child health services, should form multidisciplinary specialist ADHD teams and/or clinics for children and young people, and separate teams and/or clinics for adults. (NICE, 2018, S1.1.2)
Interagency and multidisciplinary approaches are essential whichever service model is selected. (RCPS, 2023, p.57)
Systematic assessment of functional impairment. Four guidelines made explicit reference to a more systematic assessment of functional impairment, which forms part of the DSM and ICD diagnostic criteria (see above). Three guidelines stressed the benefits of using standardised tools, such as the Weiss Functional Impairment Rating Scale (W-FIRS), to help determine ADHD severity and guide treatment.
The Weiss Functional Impairment Rating Scale (WFIRS) and the WHO Disability Assessment Schedule (WHODAS) are additional tools that supports this assessment. (RCPS, 2023, p.27)
A longitudinal approach to assessment. As noted above, the majority of the reviewed guidelines explicitly stated that assessment must be comprehensive in its focus, the consideration of developmental timelines. Many of the assessments and rating scales can only be considered a ‘snapshot’ of current difficulties. Two guidelines noted the additional value of taking a longitudinal approach to assessment, following the client over several months and years, particularly with more complex individuals.
Diagnostic reliability depends on a longitudinal assessment of the patient, together with third-party information. Assessment should be carried out on a multidisciplinary basis and may take more than one appointment. (RCPS, 2023, p.20)
Discussion
The eight guidelines included in this review were developed using different methodologies, in different service and cultural contexts and across several continents. Although they differed in their focus, they were strongly aligned in terms of the key elements of the recommended practice in the diagnosis of ADHD, regardless of whether the guidelines focused predominantly on practice with children, with adults or across the lifespan. There was strong international consensus that diagnostic assessments of ADHD should always include the following.
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Diagnosis by a registered specialist with a high level of training and experience.
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Comprehensive assessment, including a developmental and health history, assessments of physical and mental health and observer reports from school and/or family.
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Explicit reference to DSM or ICD criteria in the process and reporting of diagnoses.
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Clear consideration of differential diagnoses and alternative explanations of presenting symptoms.
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Clear evidence of assessment of impairment across multiple settings (e.g. observations, reports of others).
In addition, there was also consensus that ‘best practice’ approaches to diagnosis would include the following.
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A systematic approach to screening for comorbidity/coexisting conditions to inform diagnosis and future treatment.
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A culturally sensitive approach to diagnosis, including understanding the cultural context of symptoms, employing a strengths-based approach and using cultural and language interpreters where appropriate.
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A multidisciplinary and/or multi-agency approach, to inform both diagnosis and future treatment.
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Patient-centred and/or family-centred approaches, actively involving the individual and their family in the assessment process, tailoring the approach (and information) to their needs and preferences.
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A systematic/validated assessment of functional impairment associated with ADHD to inform support needs.
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A longitudinal approach to assessment, where the diagnosis is considered developmentally, rather than as a ‘snapshot’ taken at a single time point.
The reviewed guidelines focussed on the diagnosis of a condition that is conceptualised as biomedical in origin, with the majority taking a directly reductionist, biomedical approach to summarising research evidence. It is therefore unsurprising that the focus was strongly on medical/clinical considerations and related to symptoms and differential diagnosis. Although five of the eight guidelines included statements relating to cultural sensitivity and four included statements related to person/family-centred approaches, these were still largely considered secondary to a medical/clinical process.
In Aotearoa New Zealand, there are significant discrepancies in clinical outcomes for Māori and other groups across a wide range of mental and physical conditions (e.g. Sheridan et al., 2024). Although the reasons for this are likely to be multifactorial, the lack of consideration of culture in clinical assessment has been strongly argued to contribute to poorer outcomes for Māori (e.g. Kopua & Skirrow, 2023; Sheridan et al., 2024). In this context, several authors have recently attempted to understand the symptoms of ADHD in a Te Ao Māori (Māori world) framework, including promoting the use of the Māori language term ‘aroreretini’ (meaning ‘mind goes to many things’), the use of pūrakau (Māori creation stories) and the metaphor of the pīwakawaka (NZ fantail; see Kopua & Skirrow, 2023; Rangiwai, 2024).
Furthermore, there is good evidence that Māori are not the only group who experience inequalities in health outcomes, with significant variation in rates of ADHD diagnosis and treatment by gender, sexuality, ethnicity, culture and socioeconomic status internationally (e.g. Shi et al., 2021). Rather than being a secondary consideration, we argue that person-centred or family-centred approach, including culturally-focused care, is a pre-requisite for ensuring good quality care and achieving positive outcomes.
The findings of this study have some important implications for clinical psychologists. First, psychologists are explicitly mentioned in the guidelines as essential to the diagnostic process, either diagnosing alone or as part of a multi-disciplinary care team. However, it remains unclear whether specific training in the diagnosis of ADHD currently forms a significant part of (clinical) psychology training programmes in Aotearoa New Zealand. At the time of writing (2024), the requirement in Aotearoa New Zealand is for stimulant medication only to be prescribed on ‘special authority’ through a paediatrician or psychiatrist (Skirrow et al., 2023), which limits the utility of clinical psychologists diagnosing ADHD when working in isolation. In this context, the above synthesis provides clear standards for psychologists and others to follow in terms of providing quality diagnostic care for people with ADHD. Based on the above standards, Appendix A presents an audit tool for consumers and families to evaluate the quality of the assessments that they receive.
The key challenge for health professionals will be to minimise barriers for people with ADHD to access diagnostic and treatment services, while maintaining clear standards of care. The present study focused solely upon aspects of the ADHD guidelines that pertained to assessment and diagnosis; however, similar challenges certainly exist in access to both pharmacological and non-pharmacological treatments (Skirrow et al., 2023). Further analyses synthesising guidelines for the treatment of ADHD may be helpful in identifying areas where support services are lacking in Aotearoa New Zealand.
Acknowledgements
The author would like to acknowledge the input and feedback of members of the National ADHD Consensus Guideline Group, convened by Manatū Hauora/Ministry of Health NZ, in the development of this paper.
Disclosure Statement
The author has no financial or other conflicts of interest to disclose with regard to the research undertaken.