Abstract
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that significantly impacts various aspects of life, including school, work, family, and social relationships. The disorder has a prevalence of 6–7% in children and 4–5% in adults and commonly manifests before the age of 12. Symptoms can be categorised into two groups: attention deficit; and hyperactivity/impulsivity. As individuals age, hyperactivity symptoms generally decrease, while attention deficit symptoms exhibit less change. Attention deficit hyperactivity disorder is associated with numerous adverse outcomes, such as comorbid psychiatric disorders, academic difficulties, accidents, injuries, and increased economic burdens on society and individuals. Children and adults with ADHD have a high rate of psychiatric comorbidity, including learning disorders, autism spectrum disorder, anxiety disorders, mood disorders, tic disorders, adolescent substance abuse, and antisocial personality disorder in adulthood. Timely detection, enhanced intervention strategies, and consistent care may alleviate the clinical and economic burden of ADHD.
Introduction
Attention deficit hyperactivity disorder (ADHD) has attracted significant attention in recent years, primarily in relation to children. However, it is important to recognise that the disorder persists into adulthood as well. The severity of ADHD symptoms and the extent to which they impair functioning vary between children and adults. While numerous scientific studies have addressed ADHD, these have tended to focus exclusively on either childhood or adult ADHD. The present article aims to explore critical aspects of ADHD across all age groups, including symptomatology, functional impairment, and comorbid psychiatric disorders. The disorder is lifelong, with symptoms evolving throughout an individual's life. The extent of adult functional impairment is significantly affected by early diagnosis and effective treatment during childhood and adolescence. This article presents the characteristics of ADHD in children, adolescents, and adults, and the most common strategies used by parents and teachers to manage ADHD.
Materials and methods
A literature search was performed in electronic databases such as PubMed and Google Scholar. Searches were conducted using both the abbreviation “ADHD” and the full name “attention deficit hyperactivity disorder”, as well as individual terms such as “attention deficit”, “hyperactivity”, “child”, “adolescent”, “adult”, “costs”, and “economics”. The searches were carried out in the reference sections of relevant articles, including eleven review articles, five of which were meta-analyses. Table 1 summarises the most important reviews discussed in the present article.
List of review articles
| First author | Year of publication | Type of article | Main theme of the article | |
| 1 | Polanczyk, G.V. | 2014 | systematic review and meta-regression analysis | worldwide prevalence of ADHD |
| 2 | Thomas, R. | 2015 | systematic review and meta-analysis | prevalence estimates across countries and time, and broadening diagnostic criteria |
| 3 | Robinson, L.R. | 2022 | systematic review and meta-analysis | parental mental health, stress, and antidepressant usage risk in ADHD in children |
| 4 | Schiweck, C. | 2021 | systematic review and meta-analysis | ADHD and bipolar disorder comorbidity among adult patients |
| 5 | Cortese, S. | 2016 | systematic review and meta-analysis | association between obesity/overweight and ADHD |
| 6 | Instanes, J.T. | 2018 | systematic review | connecting adult ADHD with somatic disease |
| 7 | Buitelaar, N.J.L. | 2020 | systematic review | poor emotional self-regulation and self-control in ADHD, its role in adult domestic violence or intimate partner violence |
| 8 | Boland, H. | 2020 | systematic review and meta-analysis | early diagnosis, ADHD medication and functional outcomes |
| 9 | Harpin, V. | 2016 | systematic review | comparison of long-term self-esteem and social function outcomes in individuals with untreated and treated ADHD across childhood, adolescence, and adulthood |
| 10 | Brunkhorst-Kanaan, N. | 2021 | systematic review | ADHD patients' accidents and injuries over the lifespan |
| 11 | Chhibber, A. | 2021 | systematic review | global economic burden of ADHD over the lifespan |
Diagnosis
The most significant symptoms of ADHD include: inattention – difficulty paying attention, following instructions, and organising tasks; impulsivity – acting without forethought, interrupting others, and struggling to wait for one's turn; and hyperactivity – restlessness, excessive talking, and continuous fidgeting. A diagnosis of ADHD is based on the presence of developmentally inappropriate symptoms of inattention, hyperactivity, and/or impulsivity occurring before the age of 12, and at least two symptoms of impaired functioning [1]. According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) [1], symptoms are divided into two groups: attention deficit symptoms; and hyperactivity/impulsivity symptoms. Attention deficit symptoms include careless mistakes, difficulty sustaining attention, inattentiveness during conversations, difficulties in completing tasks and following instructions, poor organisation, an aversion to mentally challenging tasks, the frequent losing of necessary items, easy distractibility, and forgetfulness in daily activities. Hyperactivity symptoms include fidgeting, tapping the hands or feet, difficulty staying seated, restlessness, challenges with calm activities, a feeling of “always being on the go”, excessive talking, impatience, difficulty waiting one's turn, and interrupting or intruding on others. To establish a diagnosis, the presence of at least six of the above symptoms is required. These symptoms (inattentive or hyperactive/impulsive) must have become apparent before the age of 12 and must be present in at least two settings (e.g., home, school, work; with friends or relatives; and during other activities). Furthermore, there must be clear evidence that the symptoms interfere with or reduce the quality of social, academic, or occupational functioning [1]. The DSM-5 [1] does not differentiate between the nature of the symptoms in childhood and adult ADHD diagnoses. However, one crucial distinction is the number of symptoms: in the case of individuals over the age of 17, five attention deficit symptoms and five hyperactivity symptoms are sufficient to establish the diagnosis. The worldwide prevalence of ADHD is estimated to be between 5% and 11% among children, and between 5% and 7.2% among adults [2–4]. Three subtypes of ADHD are recognised: mixed type (ADHD), where symptoms of both attention deficit and hyperactivity/impulsivity are present; attention disorder type (ADD), where only the diagnostic criteria for attention disorder are met; and hyperactive type (HD), where only the symptoms of hyperactivity/impulsivity occur. During childhood, boys are affected six to eight times more often than girls, although the proportion between women and men is equal in adulthood. There are several explanations for this difference. One reason is that the pure ADD type is more common among girls during childhood. Since it is less disruptive, this type may remain unrecognised or undiagnosed and is not therefore included in the statistics. Another plausible explanation is that hyperactivity symptoms decrease in adulthood, while attention deficit symptoms change less with age. Moreover, women with other mental health problems may seek help more readily, making them more visible in the healthcare system [5].
Aetiology
Neuropsychological findings suggest that ADHD behaviours result from underlying deficits in response inhibition and abnormal executive functioning. These deficits are thought to be linked to a dysfunction in the fronto-striatal and fronto-cerebellar circuits. Anatomical differences in these regions, such as total cerebral volume and the volume of the prefrontal regions, basal ganglia, corpus callosum, and cerebellum, have been observed between children with ADHD and control subjects [6]. Several risk factors contribute to the development of ADHD, including pre- and perinatal complications, parental neglect, and low socioeconomic family status. Parental stress and depression are significantly associated with increased risk of ADHD in children, in terms of both symptoms and diagnosis. In particular, maternal stress and anxiety, prenatal stress, maternal depression, post-partum depression, and paternal depression are positively associated with ADHD. Parental antisocial personality disorder is also positively associated with ADHD overall, and specifically with ADHD diagnosis. Prenatal antidepressant use is associated with ADHD when measured dichotomously only. These findings suggest that prevention strategies promoting parental mental health and addressing parental stress could potentially have positive long-term impacts on child health, well-being, and behavioural outcomes [7].
Diagnostic procedure
Several validated behavioural scales (the ADHD Rating Scale for under 18s, and the Adult ADHD Self-Report Scale) are available, and semi-structured interviews can be used by child and adult psychiatrists to assist in the diagnostic process. In childhood, both parents and teachers contribute to the diagnostic process by providing information related to the child's behaviour and learning at home and school. Most self-administered questionnaires have versions for both parents and teachers. In many instances, if symptoms are subtle in childhood and do not cause significant functional impairment, the diagnosis is made only in adulthood. However, the identification of symptoms and impaired functioning before the age of 12 is crucial; merely observing symptoms in a cross-sectional manner is insufficient. The diagnostic process becomes significantly more complex from childhood into adolescence and adulthood due to the presence of accompanying mental illnesses or comorbidities [1, 8].
Comorbidity
Comorbidity is more the norm than the exception, occurring in two-thirds of cases from adolescence and typically involving an average of three comorbid conditions. Common comorbidities in childhood include learning disabilities, autism spectrum disorder (ASD), tic disorders and Tourette syndrome, oppositional defiant disorder, and anxiety disorders. In adolescence, mood disorders, conduct disorders, anxiety disorders (particularly performance anxiety), and psychoactive substance use disorders are prevalent. Among adults with ADHD, men commonly exhibit antisocial personality disorder and psychoactive substance use disorder, while women are more likely to experience mood disorders, anxiety disorders, and borderline personality disorders [9–11]. There is frequently an association between ADHD and academic impairments [12], accidents and injuries [13], and car accidents, among other issues [14–17].
The presence of comorbidities complicates the diagnostic process due to overlapping symptoms. The severity of the symptoms of disruptive disorders (such as oppositional defiant disorder and conduct disorder) and personality disorders may overshadow ADHD, while mood disorders and anxiety disorders may independently impair attention functions, thereby exacerbating the symptom spectrum. In childhood and adolescent mood disorders, irritability often emerges as the predominant symptom, which can easily lead to a missed diagnosis of ADHD due to the concentration problems caused by depression. With ADHD, the risk of obesity increases by 40% in individuals under 18 years of age, and by 70% in individuals over the age of 18. Drug therapy, however, can reduce this risk [18, 19]. Studies have found that ADHD in adulthood is frequently associated with sleep disorders, bronchial asthma, migraines, and gluten sensitivity [19]. The comorbidity of ADHD and bipolar disorder presents a particular diagnostic challenge. Co-occurrence is found in 1%–2% of adults, and bipolar disorder typically manifests about four years earlier in those with comorbid ADHD than in those without. With ADHD, there is increased risk of the development of bipolar disorder, and vice versa [11]. Adolescents diagnosed with ADHD are at increased risk of suicidal behaviour. In the Saving and Empowering Young Lives in Europe (SEYLE) study (2014), ADHD was confirmed in 65% of adolescents who attempted suicide, although only 22% had a prior childhood psychiatric diagnosis. Concurrently, suicidal behaviour was present in 12.7% of children and 38.9% of adolescents diagnosed with ADHD, while self-harm was found in 67.3% [20].
Other functional outcomes
Among adults with ADHD, instances of family violence and partner violence are more common, which may be attributable to the greater emotional lability, weaker emotional regulation, and lower self-control associated with ADHD [21]. From childhood to adulthood, lower school performance or graduation rates, diminished self-esteem, increased frequency of physical injuries and accidents, higher unemployment rates, increased instances of speeding, higher divorce rates, and increased criminality are all typical [5, 22]. Boland et al. discovered that early diagnosis and effective therapy exert a protective influence, mitigating the development of mood disorders, suicidal behaviour, criminality, psychoactive drug use, accidents/injuries, traumatic brain injuries, and car accidents [23]. These interventions also positively affect self-esteem and social relationships [24]. Another review indicated that, besides reducing the risk of accidents, drug therapy paradoxically increases the use of psychoactive substances [25].
Economic burden
The economic burden associated with ADHD in children, adolescents, and adults is considerable. Specific studies in North America estimate that the annual costs of individuals diagnosed with ADHD, including children, adolescents, and adults, range between $1,028.06 and $18,158.09. In Europe, the estimated costs per individual for the same patient groups range from $831.83 to $20,538.95 annually. In Asia and Australia, the economic burden analyses of ADHD include children and adolescents only, with direct per capita costs ranging between $596.27 and $2,626.09 when assessing childhood ADHD. The annual costs at national level for North America, considering all patient groups (children, adolescents, and adults), range between $2.27 billion and $20.27 billion. These costs represent 0.1% of the USA's GDP and 0.13% of Canada's GDP. In Europe, the total estimated costs of ADHD range between $356.14 million and $416.80 million. As a percentage of GDP, the estimated costs are 0.1% in Denmark, 0.15% in France, 0.12% in the Netherlands, and 0.14% in the UK. In Asia, the estimated costs are $53.16 million, while in Australia they are $27.98 million [26]. Studies examining additional aspects of ADHD, such as direct and indirect costs related to the education and justice systems, found significantly higher costs compared to studies focusing on single issues or individual age groups. National data for Hungary concerning the economic impact of ADHD in children and adolescents are not currently available.
Discussion and conclusions
If national data for Hungary concerning the economic impact of ADHD in children and adolescents were available, they would probably align with current trends. However, the distribution of youth psychiatric services in Hungary is uneven, and capacity falls far short of demand. This disparity may result in a high proportion of childhood and adolescent cases of ADHD remaining undiagnosed. Furthermore, those diagnosed with ADHD may experience limited or delayed access to effective therapy. The screening of children and adolescents for psychiatric disorders is critical, considering that four out of five adult psychiatric disorders originate in childhood [27–29]. Consequently, early diagnosis and effective treatment could potentially yield positive outcomes in adult cases.
Parents and educational institutions play a pivotal role in evaluating and managing ADHD symptoms. It is essential for parents to establish a structured environment at home, with clear expectations, daily routines, and a system of consequences and rewards. Within the school system, accommodations such as extra break time and strategic seating arrangements can assist students to stay focused and engaged. Regular communication among teachers, parents, and healthcare professionals is also beneficial in the development of effective strategies for managing ADHD symptoms [30]. The treatment of ADHD can be challenging and typically involves a combination of behavioural therapy, lifestyle adjustments, and medication. Behavioural therapy can equip individuals with coping strategies and enhance their organisational and problem-solving skills. Lifestyle modifications, such as regular physical exercise, a balanced diet, and adequate sleep, are also crucial. Stimulant medications, such as methylphenidate, are frequently prescribed, along with atomoxetine medications to improve concentration and curb hyperactivity [30].
The goal of the present article is to emphasise that ADHD is a lifelong disorder that imposes a significant economic burden. The article underscores the importance of early diagnosis and effective treatment strategies. Furthermore, it highlights the urgent need for the development and equitable distribution of national youth psychiatric services in Hungary.
Authors' contribution
IB: Main author, collecting literature, writing article, AT: Collecting literature, AS: Collecting literature, LN: Collecting literature, writing article, language corrections.
Ethical approval
NA.
Conflicts of interest/Funding
The authors declare no conflict of interest. No financial support was received for this study.
Acknowledgements
NA.
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