ADHD (Attention-Deficit/Hyperactivity Disorder)
A complete overview of ADHD (Attention-Deficit/Hyperactivity Disorder) by Geir Øgrim.
As with almost all diagnostic categories in psychiatry, the ADHD-diagnosis is based on behavioural criteria. The symptoms and diagnostic criteria are described in the DSM-5 manual DSM-5.
The job of the qualified professional is to determine:
• Are the required number of symptoms of inattention and/or hyperactivity/impulsivity present?
• Can the hypothesis be rejected that the symptoms are better understood as expressions of another diagnostic category – psychiatric or medical?
• Do the symptoms cause significant impairment in the everyday living of the patient and/or family, friends, classmates, colleagues, teachers etc.?
• Were at least some of the symptoms seen before age 12?
• Have the symptoms been observed in at least two different settings (home/school/workplace/clinic)?
• And have they been present for more than six months?
According to DSM-5 the severity of the disorder is classified as mild, moderate or severe.
Presentations (subtypes) of ADHD
The term “subtype” has been replaced by “presentation” in the DSM-5 because it is not uncommon to “move” from one subtype to another. “Hyperactive/impulsive presentation” consists of patients who meet the diagnostic criteria for hyperactivity and impulsivity, but not inattention. This category is mostly used for very young children. When they have attended school for some time the majority of them also meet the inattention criteria. The “predominantly inattentive presentation of ADHD”, often called “ADD”, consists of patients who meet the diagnostic criteria for inattention, but not for hyperactivity/impulsivity. The “combined presentation” (or “combined type”) is usually named ADHD and implies that the diagnostic criteria for inattention and hyperactivity/impulsivity are met.
“Sluggish Cognitive Tempo” (SCT)
The “predominantly inattentive presentation” (ADD) seems to consist of two quite different categories of patients. Some of them are “sub-threshold ADHD”. They meet the criteria for inattention, but not quite the required minimum of six symptoms of hyperactivity/impulsivity. The other category consists of patients who are not hyperactive or impulsive at all, but are slow, passive, often daydreaming, lacking initiative. This category has been named “Sluggish Cognitive Tempo – SCT”. Some influential professionals, such as professor Russel Barkley, argue that SCT is a separate diagnostic category, not a sub-category of ADHD. Although they share many inattention symptoms with ADHD their cognitive profile and their pattern of strengths and difficulties is different from ADHD. According to Barkley the percentage of SCT patients with a positive response to stimulant medication is much lower compared with ADHD.
How common is ADHD?
ADHD is one of the most common diagnoses in child and adolescent psychiatry. The reported incidence differs between studies, depending on the populations studied and the methods applied (rating scales vs. full diagnostic evaluation). In the Nordic countries the estimate is 3-5% of the school age population. About 65% of children diagnosed with ADHD in childhood meet the diagnostic criteria at age 18, and about 50% as adults; i.e. about 2% of the adult population. Recent American studies report higher incidences: 4.4% of adults, but only 20% of them are seeking help for the disorder.
ADHD – gender and age
In clinical samples some years ago there were nine times as many boys diagnosed with ADHD compared to girls. Today most studies report a 2:1 gender ratio when a representative sample of the population is studied. In adults the gender difference is reported to be even smaller. This change may reflect an enhanced focus on inattention symptoms. It is often claimed that “ADD” (“Inattentive presentation of ADHD”) is the female ADHD. This is just partly true. More males than females are diagnosed with ADHD. Even though about 2/3 of males are diagnosed with ADHD-C (combined presentation: Inattention + hyperactivity/impulsivity) the absolute number of males with “ADD” is larger than the number of females with “ADD”. In females most patients are diagnosed with the inattentive presentation (“ADD”). The combined type is not uncommon in females, however.
The fact that symptoms of ADHD (and other neurodevelopmental disorders) to some extent differ in males and females has been underscored in the professional literature during the last 10-15 years. The symptoms defining ADHD some decades ago basically described boys from 6 to 12 years. The present criteria include examples that also describe adult and female expressions of the disorder. Some years ago, a report based on eight ADHD teenage girls was called “Daydreamers and Chatterboxes”.
What causes ADHD?
The mechanisms behind the symptoms differ from individual to individual. If large groups are studied genetic factors explain about 60%-80%. If one parent has ADHD, the risk that the child has ADHD is 6-8 times increased (35%-54% risk). If a child has ADHD, the risk for siblings is increased 3-5 times. The risk for mothers is 3-4 times increased and for fathers 5-6 times increased.
Studies have shown that many genes, at least 40, are associated with ADHD. The number of genes involved for one patient may be much smaller, and different from patient to patient. This fact can account for the heterogeneity of the disorder; the symptom patterns may differ considerably between patients.
The genes involved in ADHD are not specific for the diagnosis but are also associated with other diagnostic categories. This is an indication that the brain does not operate in accordance with our present diagnostic system.
The impact of psychosocial factors is commented in paragraph “Criticism of the ADHD diagnosis”.
Several medical conditions should be considered, depending on the information available for the patient in focus. Such conditions could be alternative explanations (differential diagnoses) or disorders that should be diagnosed along with ADHD (comorbidities). Some examples are: Impairments of hearing and vision, epilepsy, cerebral palsy or other neurological disorders, disorders of sleep and eating, symptoms related to use of legal or illegal drugs, Foetal Alcohol Spectrum Disorder (FASD), and a whole host of genetic ("behavioural phenotype") syndromes (including Fragile-X-syndrome etc.).
Medical and developmental history: A structured interview with the patient and/or close relatives such as parents, are commonly used. Questionnaires that also include space for extra information, followed by a feedback session with the informant, is an alternative.
Clinical interview: The professional completes an interview with the patient and/or other significant informants such as parents, partners, teachers etc. The questions are related to the symptoms described in the diagnostic manual. Do the symptoms lead to impairments in daily living? Can the informant come up with examples?
Such instruments are tried out on large representative samples from the general population. The patient scores are compared with the norms based on population data. This tells the clinician if a cluster of symptoms, such as inattention, is within the "normal" range or indicate deviance. The CBCL (Child Behavior Checklist and the FTF (5-15) questionnaire are examples of scales mapping many psychological domains. The Conners 3 rating-scale has a primary focus on ADHD, but also screens for emotional and behavioural problems.
A test of general intelligence is commonly used. A low score could be an indication of intellectual disability as an alternative explanation of the ADHD symptoms. Some patterns within the test can support a diagnosis of ADHD but are not included in the diagnostic criteria. (Scores on working memory and/or perceptual speed are often lower than scores of general intelligence).
Computerized tests of attention are also widely used. Problems of so-called executive functions are often seen in ADHD. Tests measuring problem solving, planning, working memory and inhibition can contribute to the general assessment of the patient, and may contribute to the global diagnostic conclusion.
To see the patient in his/her natural environment (home, school, workplace), or in an interview or test situation, can reveal supplementary information that should be considered.
Criticism of the ADHD diagnosis
• “Too many young people are diagnosed with ADHD, giving them a stigma that they don’t need.” Professionals should take such criticisms seriously. If the number of people diagnosed with ADHD does not exceed the estimated prevalence, there is no general over-diagnosing. The competence of the professionals diagnosing ADHD is important in order to avoid over- as well as under-diagnosing the disorder. In general diagnoses are meant to guide understanding of the problems and point out the most relevant treatment options. Informing the patient and the people close to him/her about ADHD; what it is and what it is not, what can be done etc. is important to avoid stigma.
• “The causes of the symptoms may not be ADHD.” This is true, as mentioned above.
Several medical and psychiatric causes must be considered. It is claimed that psychosocial factors such as neglect, trauma, posttraumatic stress disorder (PTSD) and reactive attachment disorder may cause similar symptoms. This is a very complex issue, partly because ADHD in patients and family members may increase the risk of being exposed to such psychosocial loads. Whenever relevant, all issues, ADHD, trauma, neglect etc. must be considered.
• “Objective methods for diagnosing ADHD are lacking. There is too much subjectivity involved.” Objective methods that can supplement the present criteria based on behaviour are lacking. The issue of including objective methods (“biomarkers”) as supplements to the behavioural criteria was discussed during preparation of the present diagnostic manual (DSM-5). A limited number of supporting research studies is one reason that such criteria were not included.
• “The pharmaceutical industry ‘pushes’ a high prevalence of ADHD.”
To be approved by health authorities all medications must document effects and side-effects in so called randomized double-blind placebo-controlled studies, which is the highest scientific level of documentation. (When medication effects are evaluated, no one knows if the patient received “real” medication or a “fake pill”). Researchers doing medication studies are committed to an agreement that all treatment results, positive as well as negative, will be published, regardless of the institution financing the study.
For many years the interaction between the pharmaceutical companies and the prescribing doctors in the Nordic countries has been strictly regulated to secure that the drug prescription is purely professional.
Alternative and additional diagnoses
Most patients diagnosed with ADHD meet the criteria for at least one other diagnosis. This is even more common in adults than in children. As mentioned above, the diagnostic process includes an evaluation of alternative explanations of the symptoms before diagnosing additional disorders (comorbidities). In children the most common comorbid conditions are: Oppositional Defiant Disorder (ODD; Conduct Disorder), Learning Disabilities including dyslexia, language disorders, autism spectrum disorder/Asperger syndrome, Tourette syndrome (involuntary movements and sounds, Anxiety disorders depression, sleep disorders, Obsessive Compulsive Disorder, Reactive Attachment Disorder (RAD) and Post Traumatic Stress Disorder (PTSD), anorexia / bulimia. The same comorbid disorders are also seen in adults. Bipolar disorder and substance use disorder are seldom diagnosed in children but are common in adult ADHD.
The fact that a developmental disorder such as ADHD very often is accompanied by one or more additional disorders is a basic challenge to the diagnostic system in psychiatry. This system invites us to think in separate categories (diagnosis A or B), which does not reflect reality. The concept ESSENCE accounts for this by pointing out that children with one developmental disorder very often also meet the criteria for one or more additional diagnoses, and that a broad interdisciplinary examination is recommended. It is not uncommon that a preschool child is diagnosed with a language disorder. A few years later the same child may be diagnosed with ADHD, and as a young teenager a third examination concludes with Autism Spectrum Disorder / Asperger syndrome.
Another challenge to the diagnostic system in psychiatry is the diffuse border between normality and pathology. Discrete diagnostic categories, (such as a broken arm – yes or no), are uncommon. Where to put the diagnostic threshold, separating normal and abnormal, can be challenging. Two qualified professionals considering all relevant information may not always reach the same conclusion.
Treatment of ADHD
To keep in mind: For patients with ADHD (and other diagnoses) quality of life is more important than reduction of symptoms.
A broad interdisciplinary diagnostic evaluation is an important part of the treatment. The patient and others concerned such as parents, siblings, teachers, partners etc. should receive a feedback from the evaluation that is meaningful to them.
Having a diagnosis is not always easy but can lead to new and more fruitful perspectives on the patient’s problems. Psychoeducation, i.e. structured information about the disorder, often group based, should be offered to patients and/or relatives.
A broad evaluation should pinpoint the strengths and difficulties of the patient and guide the treatment plan. There are numerous publications about this, such as:
The term treatment implies changing the patient in some way to reduce suffering and enhance quality of life. One should not forget the opposite perspective: In what ways can the environment be changed to better fit the ADHD patient?
Health personnel are committed to the principle of evidence-based practice. The treatments offered or recommended should be supported by scientific studies of high quality, and/or be recommended by professional guidelines. Most treatments offered do not meet these criteria. Some of the non-documented treatments may prove effective in future research. Other treatments may be helpful to subgroups of the patients. The patient organizations and governmental guidelines usually contain an overview of recommended treatment options. CHADD, NICE.
Medical treatment of ADHD
Millions of ADHD patients worldwide have been treated with stimulant medication (link) for many decades. The active substances are usually methylphenidate or dextroamphetamine. In about 70% of the patients these medications significantly reduce the symptoms without bothersome side-effects. To find the best medicine and the optimal dose can be time consuming, and the ADHD diagnosis does not guarantee a positive medication effect. Even healthy subjects can have a small attention enhancing effect of stimulants. To decide if the clinical effect is significant and meaningful in a patient is not always easy because informants may differ in their evaluations. (The present author (GØ) is engaged in research aiming to predict medication response based on testing the electrical brain activity (EEG) during an attention task on and off medication. (Ogrim, G & Kropotov J, D 2019)
Non-medical treatments of ADHD
NICE guidelines, and similar national guidelines, usually underscore that medication seldom is the sole treatment needed. Psychoeducation and adaptations of the environment to the needs of the patient are highlighted. For children Parent Management Training is classified as evidence-based treatment, for example:
An alternative parent training approach is Collaborative Problem Solving.
In schools the pedagogical approach should be based on an understanding of common ADHD challenges. Common challenges are related to planning / “thinking ahead”, organizing, focusing, staying on task, self-motivation for tasks without “inborn motivation” (such as video games), mental effort and control of impulses.
Other commonly suggested treatments for ADHD are: Dietary treatment, physical exercise, neurofeedback and working memory training.
More on ADHD
Recently published articles on ADHD
- ASD with ADHD vs. ASD and ADHD alone: a study of the QbTest performance and single-dose methylphenidate responding in children and adolescents (2022)
Monitoring medication response in ADHD: what can continuous performance tests tell us? (2022)
Verbal working memory and processing speed: Correlations with the severity of attention deficit and emotional dysregulation in adult ADHD. (2022)
Neuroimaging findings in children with cerebral palsy with autism and/or attention-deficit/hyperactivity disorder: a population-based study. (2022)
- Attention-deficit/hyperactivity disorder with developmental coordination disorder: 24-year follow-up of a population-based sample. (2021)
ADHD should be considered in adolescents with type 1 diabetes and poor metabolic control.
- Interpersonal trauma and its relation to childhood psychopathic traits: what does ADHD and ODD add to the equation? (2021)
- Long-term medication for ADHD and development of cognitive functions in children and adolescents. (2021)
- The road to diagnosis and treatment in girls and boys with ADHD - gender differences in the diagnostic process (2020)
- Using the five to fifteen-collateral informant questionnaire for retrospective assessment of childhood symptoms in adults with and without autism or ADHD (2020)
- Indexing Executive Functions with Test Scores, Parent Ratings and ERPs: How Do the Measures Relate in Children versus Adolescents with ADHD? (2020)
- Event Related Potentials (ERPs) and other EEG Based Methods for Extracting Biomarkers of Brain Dysfunction: Examples from Pediatric Attention Deficit/Hyperactivity Disorder (ADHD) (2020)
- Autism spectrum disorder and attention-deficit/hyperactivity disorder in children with cerebral palsy: results from screening in a population-based group (2020)