There has been a great deal of debate surrounding the negative effects of labelling individuals, as ‘different’ or ‘disordered’. Indeed, if all you do is label the individual as having ADHD, then yes the process is at a minimum pointless and potentially very damaging. However, in order to find a solution to a problem, one must first know what that problem is, and even more importantly how others with similar difficulties have managed to cope with or overcome the same challenges.

Unfortunately, in most (if not all) jurisdictions around Europe where services exist, and resources are made publically available for ADHD (e.g., behaviour therapy or medication re-imbursement), these are not provided without a diagnosis, which is particularly true in an educational setting (Clark, Carr-Fanning, & Norris, 2011; Desforges& Lindsey, 2010).

There is also a big difference between suspecting someone has ADHD, and knowing it for sure, not to mention finding out the unique strengths and needs of the individual. Parents, teachers, and individuals are encouraged to find out as much information as possible about the condition; this website will provide you with an overview of the issues. However, it is essential that one proceed cautiously and do not attempt to diagnose the disorder without the appropriate professional assistance. Without the proper identification and treatment ADHD can have serious long-term consequences.

There is no blood or other biological test to determine if someone has the disorder. Accurately diagnosing ADHD, any co-existing difficulties, and co-morbid disorders is complicated and highly specialized process; which requires a comprehensive assessment by a well-trained and experienced professional.

Despite numerous recommendations, clinical guidelines are few and far between. This review attempts to condense these, so that they are accessible to professional and lay readers. For those who would like more information, among the most reliable and comprehensive sources of best practice in the area are the UK’s NICE (National Institute for Clinical Excellence) Guidelines (2009). In addition, for those interested in adult assessment and treatment Sandra Kooji’s (2010) book is recommended.


There are no universally applicable rule for which professionals can or should diagnose ADHD, and the procedures and best-practice recommendations vary across Europe; for those wishing to know more should reference our 2011 Survey, which is available for purchase on the website.

Traditionally, psychiatrists, clinical psychologists, paediatricians, and neurologists are usually capable and qualified to diagnose, however, this does not represent an exhaustive list of professionals, nor does it suggest that everyone shall do so. Medical and mental health professional’s work under strict ethical codes, an individual’s background, training, and experience will impact upon their competencies. It is important to remember that ADHD is highly complex condition, and one of 200+ distinctly different disorders present within the DSM-IV-TR. In addition, certain professionals tend to specialize in one or a select number of conditions; with a good working knowledge of the others. However, them may refer the individual to a colleague or clinic with more specialized services, and this is not necessarily a bad sign for the individual.

Before embarking on the process it is important that the parent or individual researches the condition and their rights under national law. This is where local or national organizations and support groups are extremely important. Self-support and patient advocates tend to have amassed considerable clinical and experiential knowledge. They or their members can often inform individuals about their rights, recommend professionals and services, and provide advice and support before, during and after the diagnostic process.


As with the majority of psychiatric and psychological disorders, there are no medical tests which determine the presence or absence of the condition.Advances in neuroimaging have contributed greatly to our understanding of ADHD, however, their use in diagnosis is decades away (Rubia, 2011). Therefore, diagnosis depends on observing behaviour deficits and assessing the underlying symptoms of attention, impulsivity, and hyperactivity (or combinations thereof).

ADHD is recognized as a legitimate and impairing condition, however, there are no universally applied set of diagnostic criteria: the most common texts are the DSM-IV and ICD-10 (Hinshaw et al., 2011). These guides lay out the criteria which should be used by doctors and clinicians when making a diagnosis, however, the criteria between the two differs substantially. These must meet the coterie stipulated in either the DSM-IV-TR or ICD-10. There are other systems out there. However, here the two most prevalent texts are discussed.


  1. Meet the criteria stipulated in the DSM-IV-TR or ICD-10
  2. Are associated with moderate impairments in one or more are of functioning (e.g., psychological, social and academic) as assessed by interview and/or observations across multiple settings
  3. Occur persistently, across two or more settings (e.g., school / work and home).

Attention Deficit Hyperactivity Disorder (ADHD) is diagnosable under the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (Text Revision) (DSM-IV-TR) and Hyperkinetic Disorder (HKD), is the disorder based on criteria laid out in the International Classification of Diseases, 10th revision (ICD-10).

According to the DSM-IV-TR, published by the American Psychiatric Association (APA) (2001), ADHD is an umbrella term which the individual can be one of three ADHD sub-types:

  1. Predominantly inattentive
  2. Predominantly hyperactive-impulsive
  3. Combined

The International Classification of Diseases (ICD-10), published by the World Health Organization (WHO, 1994), requires symptoms in all three areas:inattention (6+), hyperactivity (3+), andimpulsivity (+1) for a diagnosis of Hyperkinetic Disorders (HKD). As such, HKD is often considered to be a more server form of ADHD the combined sub-type. Thus, prevalence ratings do drop considerably when it is applied (Polanczyk et al., 2007).

Not only must symptoms be present they must also cause a functional impairment, for at least six months. In addition, the onset (or the first appearance of symptoms and impairment) must be prior to seven years of age.

Both texts are currently under revision and due to be released in the coming months. Most notably, the DSM-IV subtypes are to continue and recognition given to differential symptoms in older adolescents and adults; and recommendations for the age of onset to be extended to 11 years has been made. In addition, the ICD-11 does give recognition to the existence of an inattentive subtype of the condition.


The occurrence of symptoms alone is insufficient for a diagnosis, their impact must also represent a degree of functional impairment, and this cannot be confined to a single environment, such as school. As such, the symptoms must impact aspects of the individual’s life to a noticeably maladaptive degree; this is usually based on developmentally inappropriate levels when compared to their peers.

More simply, symptoms need to interfere with the individual’s ability to function in the important aspects of their life, such as personal care and self-management, academic or occupational performance and/or achievement, personal relationships with their peers, authority figures, and within social and community settings. An area often fraught with difficulties when one or more family member has ADHD is the home life.

Examples include:

  • They are unable to make and keep friends
  • They are unable to perform academically despite having the ability to
  • They are unable to live independently despite it being typically expected of their age
  • They are unable to hold down a job

Another stipulation is that the symptoms functional impairment must be present in multiple situations; i.e., evidence from more than one setting is required, for example, home, school, workplace, or social functioning. Adversely impact on the current functioning and/or their development and psychological well-being


This aspect is crucial, because certain neurodevelopmental disorders, learning difficulties, psychiatric disorders, psychological problems, or life events (e.g., bereavement) can mimic ADHD-type symptoms. However, such conditions, disorders, or difficulties can (and often do) exist concurrently. Therefore, what one needs to establish is whether the impairment in functioning is attributable to the ADHD alone, or whether there is a different primary disorder, or whether the ADHD exists concurrently with one or more diagnosable issue(s).



The professional engages in at least one in-depth session of questioning to establish the diagnostic criteria, and rule out possible mimicry.

At this stage and during psychological and educational assessment, the educational, occupational, and social adjustment should be assed; the presence of functional impairment.


ADHD-type behaviours exist in everyone, therefore, what the clinician needs to establish is the degree in relation to established norms. In addition, since there are often parent, teacher, and self-report forms of these they can be extremely helpful to assessment symptoms across settings, and their level of maladaptivity without actual observations, or when they are referring to childhood symptomology. However, both scales and observations are obviously preferable to avoid any possible bias being introduced.

It is important to remember that while they can be a helpful tool and adjunct during the process, a diagnosis of ADHD should never be made solely on the basis on rating scales.


Undiagnosed disorders, mimicry (e.g., thyroid disorder, hearing impairment, etc.


Educational and clinical psychologists can assess for psychosocial and cognitive problem areas, such as learning difficulties, executive function impairment (e.g., memory), and skill deficits


For children and young people at a minimum the diagnostic process should always include a clinical interview, with the parent and the child or young person themselves, however, for those under 8 years this is at the discretion of the professional. It is strongly recommended that the children be included in the process to the extent that they are capable, and that caution is exercised when making assumptions about their level of incapability (Beauchamp & Childers, 2006; UNCRC, 1989).

An interview with the child’s teacher or teachers, as appropriate, can be included and where possible they should always be included in the process, in addition, observations of the child across settings is advisable. However, due to resource issues this may not occur in practice. The use of parent and teacher rating scales can facilitate this process, however, while they can be a good source of information they should never be used alone to diagnose ADHD.

For adults a clinical interview is again required, and the use of rating scales, such as the can facilitate the onset and course of the ADHD in their childhood. Usually, someone who observed their behaviour during childhood, such as a parent could assist with this process, as would any educational or clinical reports for that period.

Symptoms have a tendency to manifest differently in older adolescents and adults. Inattention tends to remain consistent, whereas, hyperactivity and impulsivity can become internalized to the point where the hyperactive symptoms associated with childhood ADHD are of little use during the diagnostic process as age advances.

Authors of the article: Kate Carr-Fanning and Conor Mc Guckin, the School of Education, Trinity College Dublin, 2012.

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