Disease Burden of Autism Spectrum Disorder and Attention - Deficit/Hyperactivity Disorder in the 0-14 Age Group across 204 Countries and Regions from 1990 To 2021.

Attention Deficit Hyperactivity Disorder (ADHD) is a major neurodevelopmental disorder among adolescents and young adults (AYAs) worldwide. However, there is still insufficient understanding of the burden and trends of this condition. This study aims to assess the trends in the global, regional, and national burden of ADHD among AYAs aged 10-24 years from 1990 to 2021. Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, our study reports estimates of the incidence, prevalence, and disability-adjusted life-years (DALYs) of ADHD among AYAs at the global, regional, and national levels, including the corresponding rates and 95% uncertainty intervals (UIs). We also analyzes the trends in the burden of ADHD from 1990 to 2021 from both global and local perspectives, specifically by Estimated Annual Percentage Change (EAPC) and Average Annual Percentage Changes (AAPCs). Additionally, these global trends are further examined according to age, sex, and Socio-Demographic Index (SDI). Globally, the incidence of ADHD among AYAs decreased slightly from 12.61 per 100,000 population in 1990 to 11.89 per 100,000 population in 2021, with an EAPC of -0.61% (95% CI -0.79 to -0.43) and AAPCs of -0.17% (95% CI -0.28 to -0.05). The prevalence rate decreased slightly from 2,381.82 per 100,000 population in 1990-2,173.48 per 100,000 population in 2021, with an EAPC of -0.58% (95% CI -0.63 to -0.53) and AAPCs of -0.44% (95% CI -0.47 to -0.42). The rate of DALYs decreased from a 1990 rate of 30.31 per 100,000 population to 26.56 per 100,000 population in 2021, with an EAPC of -0.58% (95% CI -0.63 to -0.52) and AAPCs of -0.44% (95% CI -0.47 to -0.42). In terms of gender, incidence, prevalence and rates of DALYs were higher in males than in females during the same period. In terms of age, the incidence rate originated only from the 10-14 years age group, and only prevalence and DALYs rates were present in the 15-19 years age group and 20-24 years age group and the trend analysis results were correlated with the age group. According to SDI quintiles, incidence, prevalence, and rates of DALYs for ADHD had the highest increases from 1990 to 2021 in areas with a High-middle SDI or High SDI. However, the relationship between incidence, prevalence, and DALYs rates and SDI was nonlinear, and regionally, Australasia had the highest incidence, prevalence, and DALYs rates in 2021, with Western Europe and East Asia having the largest increases in incidence, prevalence, and DALYs rates. In terms of countries, Australia has the highest incidence, prevalence and DALYs rates in 2021, while the UK, Spain and China have the highest rate increases. Over the past 30 years, there has been a general downward trend in the incidence and prevalence of ADHD and in the rate of DALYs worldwide. However, phased studies have shown less homogeneous trends in recent years, which may be related to changes in the level of socioeconomic development, diagnostic criteria, and therapeutic approaches. Therefore, it is necessary to continue to promote research on the accuracy and universality of ADHD diagnosis and treatment in the future, with a view to further reducing the global health burden of ADHD.

Autism spectrum disorders (ASDs) are persistent disabling neurodevelopmental disorders clinically evident from early childhood. For the first time, the burden of ASDs has been estimated for the Global Burden of Disease Study 2010 (GBD 2010). The aims of this study were to develop global and regional prevalence models and estimate the global burden of disease of ASDs. A systematic review was conducted for epidemiological data (prevalence, incidence, remission and mortality risk) of autistic disorder and other ASDs. Data were pooled using a Bayesian meta-regression approach while adjusting for between-study variance to derive prevalence models. Burden was calculated in terms of years lived with disability (YLDs) and disability-adjusted life-years (DALYs), which are reported here by world region for 1990 and 2010. In 2010 there were an estimated 52 million cases of ASDs, equating to a prevalence of 7.6 per 1000 or one in 132 persons. After accounting for methodological variations, there was no clear evidence of a change in prevalence for autistic disorder or other ASDs between 1990 and 2010. Worldwide, there was little regional variation in the prevalence of ASDs. Globally, autistic disorders accounted for more than 58 DALYs per 100 000 population and other ASDs accounted for 53 DALYs per 100 000. ASDs account for substantial health loss across the lifespan. Understanding the burden of ASDs is essential for effective policy making. An accurate epidemiological description of ASDs is needed to inform public health policy and to plan for education, housing and financial support services.

Objective To investigate the prevalence of autism spectrum disorders (ASD), attention deficit/hyperactivity disorder (ADHD), and related co-occurring conditions in Faroese children and examine differences regarding sex and age at diagnosis. It is hypothesised that prevalences are increasing, are higher in boys compared to girls, that girls are diagnosed later than boys, and that stress-related mental health conditions are related to higher age at diagnosis. Methods A retrospective study was conducted with children born from 2004 to 2022, using health register data on patients diagnosed with ASD or ADHD at the National Hospital of the Faroe Islands. A total of 479 children were included in the study. Prevalence rates were calculated alongside age- and sex-standardised measures, including the mean age at diagnosis and the frequency of co-occurring conditions, with all estimates including 95% confidence intervals (CI). Results Prevalence of ASD was 2.7% (95% CI: 2.4–3.0), with a higher prevalence among boys (3.4%, 95% CI: 2.9–3.9) compared to girls (2.0%, 95% CI: 1.6–2.4). Prevalence of ADHD was 2.9% (95% CI: 2.6–3.3), higher in boys (3.8%, 95% CI: 3.3–4.4) than in girls (2.0%, 95% CI: 1.6–2.4). Girls received diagnoses of ASD and ADHD at later ages—on average, 12.7 years for ASD, 11.9 years for ADHD, compared to 9.5 and 10.8 years, respectively, for boys. The mean ages at diagnosis were 14.2 years for ASD and 12.3 years for ADHD for those children who also presented with stress-related mental health conditions. Children without these conditions were diagnosed at mean ages of 9.4 and 10.3 years, respectively. Conclusion Childhood ASD and ADHD prevalence in the Faroe Islands was 2.7% and 2.9%, with sex distributions consistent with international patterns and frequent co-occurring conditions. Differences in diagnostic age linked to stress-related mental health conditions were observed, though these findings require cautious interpretation. Earlier identification may facilitate timelier intervention and reduce subsequent mental health risks.

To assess the effect on prevalence estimates of using different algorithms to identify children with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in healthcare data. Three algorithms were developed and run on administrative/research data in Finland, France (Haute Garonne), Italy (Emilia Romagna), Norway and Wales: (1) ≥ 1 ADHD or ASD diagnoses recorded in specialist settings, (2) ≥ 2 ADHD or ASD diagnoses recorded in primary care and (3) ≥ 1 prescription for medication to manage ADHD. Prevalence rates per 1000 children for each algorithm were calculated. 3,130,162 children (born 1996-2020) with 29,291,204years of follow-up were included. ADHD prevalence per 1000 children in specialist settings ranged from 3.9 (Emilia Romagna) to 24.1 (Finland); and was 7.0 in primary care (Finland). Based on prescriptions, ADHD prevalence ranged from 0.1 (Emilia Romagna) to 9.9 (Haute Garonne). ASD prevalence in specialist settings ranged from 5.6 (Wales) to 9.7 (Finland), and in primary care from 1.0 (Finland) to 2.0 (Wales). Prevalence of ADHD and ASD was greater among children with longer follow-up. In Finland and Wales, 1.7% and 19.4% of children were diagnosed with ASD in primary care only respectively. The male:female ratio was 3-4:1. Whilst there was considerable geographical variation in the length of follow-up available, and prevalence of ADHD and ASD, specialist diagnoses recorded in healthcare data were key to identifying children with these disorders. These data sources can be complemented by using primary care diagnoses and prescription data to identify affected children more comprehensively.

Autism spectrum disorder (ASD) substantially contributes to the burden of mental disorders. Improved awareness and changes in diagnostic criteria of ASD may have influenced the diagnostic rates of ASD. However, while data on trends in diagnostic rates in some individual countries have been published, updated estimates of diagnostic rate trends and ASD-related disability at the global level are lacking. Here, we used the Global Burden of Diseases, Injuries, and Risk Factors Study data to address this gap, focusing on changes in prevalence, incidence, and disability-adjusted life years (DALYs) of ASD across the world. From 1990 to 2019, overall age-standardized estimates remained stable globally. Both prevalence and DALYs increased in countries with high socio-demographic index (SDI). However, the age-standardized incidence decreased in some low SDI countries, indicating a need to improve awareness. The male/female ratio decreased between 1990 and 2019, possibly accounted for by increasing clinical attention to ASD in females. Our results suggest that ASD detection in low SDI countries is suboptimal, and that ASD prevention/treatment in countries with high SDI should be improved, considering the increasing prevalence of the disorder. Additionally, growing attention is being paid to ASD diagnosis in females, who might have been left behind by ASD epidemiologic and clinical research previously. ASD burden estimates are underestimated as GBD does not account for mortality in ASD.

To investigate the prevalence of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in a population-based birth cohort and correlate the findings with prenatal and perinatal factors. We hypothesized that children born preterm, having experienced preeclampsia or maternal overweight, would have an increased risk of ADHD or ASD. A Swedish cohort of 2666 children (1350 males, 1316 females) has been followed from birth with parental and perinatal data. The National Board of Health and Welfare's registries were used to collect data regarding perinatal status and assigned diagnoses at the age of 12 years. The prevalence of ADHD and ASD was 7.6% and 1.1% respectively. Maternal obesity early in pregnancy resulted in a three-fold increased risk of ADHD in the child. Similarly, paternal obesity resulted in a two-fold increased risk. The association was significant also when adjusted for sex, preterm birth, smoking, and lower educational level. The prevalence of ASD was too low for statistically relevant risk factor analyses. Our results corroborate earlier findings regarding prevalence and sex ratio for both ADHD and ASD. Maternal body mass index and preterm birth were correlated with an ADHD diagnosis at the age of 12 years.

The evolving global burden of ADHD: A comprehensive analysis and future projections (1990-2046).

Aims1.Literature survey on ADHD in Down’s syndrome2.To evaluate the prevalence of Attention Deficit hyperactivity Disorder (ADHD ) and Autism in Down’s Syndrome using Light House Child development center Down’s Syndrome...

There is a high prevalence of neuropsychiatric disorders in myotonic dystrophy types 1 and 2 (DM1 and DM2), including autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) in DM1, and depression and anxiety in both DMs. The aim of this systematic review and meta-analysis was to estimate the prevalence of ASD, ADHD, depression and anxiety in the population with DM, and their association with disease onset. A systematic search of Medline, Scopus, Web of Science, and the Cochrane Library was conducted from inception to November 2023. Observational studies estimating the prevalence of these disorders in DM1 or DM2 were included. A meta-analysis of the prevalence of these disorders and an association study with disease onset by prevalence ratio meta-analysis were performed. Thirty-eight studies were included. In DM1, the prevalence of ASD was 14%, with congenital onset being 79% more common than juvenile onset, while the prevalence of ADHD was 21%, with no difference between congenital and juvenile onset, and the prevalence of depression and anxiety were 14% and 16%. Depression was more common in the adult onset. Finally, the prevalence of depression in DM2 was 16%. A higher prevalence of neuropsychiatric disorders is observed in individuals with DM1 and DM2 than in the general population. Therefore, actively screening for congenital and juvenile neurodevelopmental disorders in DM1 and emotional disorders in DM1 and DM2 may improve the quality of life of those affected.

Background: Social-communication difficulties, a hallmark of ASD, autism spectrum disorder (ASD) are often observed in attention – deficit/ hyperactivity disorder (ADHD), although are not part of its diagnostic criteria. Despite sex differences in the prevalence of ASD and ADHD, research examining how sex differences manifest in social and communication functions in these disorders remains limited, and findings are mixed. This study investigated potential sex differences with age in social adaptive function across these disorders, relative to controls. Method: One hundred fifteen youth with ASD, 172 youth with ADHD, and 63 typically developing controls (age range 7–13 years, 75% males) were recruited from the Province of Ontario Neurodevelopmental Disorder (POND) Network. Social adaptive function was assessed using the Adaptive Behavior Assessment System-Second Edition (ABAS-II). The proportions of adaptive behaviors present in each skill area were analyzed as a binomial outcome using logistic regression, controlling for age, and testing for an age-by-sex interaction. In an exploratory analysis, we examined the impact of controlling for core symptom severity on the sex effect. Results: Significant sex-by-age interactions were seen within ASD in the communication (p = 0.005), leisure (p = 0.003), and social skill areas (p < 0.0001). In all three areas, lower scores (indicating poorer function) were found in females compared to males at older ages despite females performing better at younger ages. There were significant differences in the sex-by-age interactions in the social and leisure domains between those with ASD and typically developing controls, with typically developing females showing better scores at older, compared to younger, ages. There were also significant differences in the sex-by-age interactions between ASD and ADHD on the social and leisure domains, as females with ADHD consistently scored higher on social skills than males across all ages, unlike those with ASD. Sex differences across age in the social domains for ADHD were similar to those in the typically developing group. Conclusion: Sex differences in social and communication skill areas were observed between ASD and ADHD, and typically developing controls, with females with ASD performing worse than males at older ages, despite an earlier advantage. These findings reinforce the need to take a developmental approach to understanding sex differences which may have diagnostic, prognostic, and treatment implications.

The prevalence of autism spectrum disorder (ASD) has increased markedly over the past 40 yr (1). It was reported to be 4-10/10,000 by the early 1990s, but increased to 20-116/10,000 after the year 2000, and was even up to 1/88 in recent studies (1, 2). The prevalence of ASD in Korea was reported to be as strikingly high as 2.64% (3). The change in the prevalence of attention deficit hyperactivity disorder (ADHD) is not as dramatic as that of ASD, but the overall trend has been similar over the past 10 yr. A survey from the United States reported that ADHD increased from 7.8% to 9.5% between 2003 and 2007 (4). There are several different interpretations as to how this change occurred within only decades. The first possible influential factors are diagnostic substitution and changes in the definitions of the diseases. In particular, some studies have suggested that diagnostic substitution (diagnosing as one condition at one time and subsequently as another condition at another time) has played an important role in the increasing prevalence of autism over time. Diagnostic substitution is closely related to changes in the diagnostic system, particularly of the broadened concept of ASD. Autism was first narrowly defined by Leo Kanner in 1943, but after the 1980s, the diagnostic system started to acknowledge milder phenotypes. The most dramatic change was listing Asperger's disorder (social impairment without language delay) and pervasive developmental disorder not otherwise specified (PDD NOS; individual who fails to meet age criteria or does not display all the key elements of autism or other subtypes of PDDs) in the DSM-IV (1994). Regarding ADHD, diagnostic substitution has not played as large a role as in ASD because the diagnostic criteria have largely remained unchanged since 1980. However, possible confounders may contribute to the variable prevalence of ADHD. The most problematic notions of the DSM-IV criteria for ADHD are functional impairment and dysfunction evident in at least 2 different settings. As the degree and range are poorly defined and are dependent on the raters, the criteria may allow room for a subjective judgment of diagnosis. The second potentially influential factors are the methods of case identification and source of data; these factors raise one of the most essential questions about whether the increased prevalence reflects a true upsurge in incidence or an increased discovery rate. In particular, when the cases are identified from a pre-registered database, such as national registers, the prevalence can be significantly biased by accessibility to healthcare and education services, the attitude of parents toward mental health problems, and the clinician's experience and level of expertise. As both ASD and ADHD are diagnosed based on behavioral profiles reported from multiple data sources and direct observation, factors affecting prevalence may be present even in population-based epidemiological studies. Typically, first-line screening depends on the checklists completed by parents, teachers, or both. Therefore, the positive screening rate might be influenced by the sensitivity of the screening instruments, the level of the raters' understanding of the questionnaire, and their pre-existing concerns regarding the disease screened. Also, the participation rate for the screening and confirmation process can be a major issue (nonresponse bias). Diagnoses are also influenced by the instruments used for the diagnostic confirmation. Thus, epidemiological studies should be cautiously interpreted as to whether these potential confounders have been carefully controlled, particularly when the reported prevalence is extremely high. The third and most controversial element in the increased prevalence is the environmental contribution to the incidence of ASD and ADHD. Environmental influences can be accounted for by gene-environmental interactions or epigenetic modification of risk gene expression. Suggested factors for ASD are mainly biological, such as intrauterine infection, advancing maternal age, air pollution, organophosphates, and heavy metals (5, 6). The relationship between the rapid increase in autism and MMR vaccinations was once debated very intensely; however, large-scale epidemiological studies have clearly disproven the possible relationship between those factors (7). The environmental risk factors for ADHD include prenatal substance exposure, heavy metals, maternal folate levels, obesity, food additives, early traumatic events, and maternal stress (8). Compared to ASD, there might be a higher possibility that recent environmental changes have contributed to the increase in ADHD. However, it has yet to be confirmed whether there is a direct, quantitative correlation between these factors and increased prevalence. Although the increase in ASD and ADHD is verging on a social issue as well as a public health concern, the underlying etiology is likely a multi-factorial one, much more complicated than the phenomenon itself. Prospective studies with identical protocols are needed for measuring genuine incidence. In the long run, the establishment of biological markers of ASD and ADHD could provide clearer answers by clarifying debates over the stability of the diagnostic system and its reliability.

SummaryBackgroundHigh-quality estimates of the epidemiology of the autism spectrum and the health needs of autistic people are necessary for service planners and resource allocators. Here we present the global prevalence and health burden of autism spectrum disorder from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 following improvements to the epidemiological data and burden estimation methods.MethodsFor GBD 2021, a systematic literature review involving searches in PubMed, Embase, PsycINFO, the Global Health Data Exchange, and consultation with experts identified data on the epidemiology of autism spectrum disorder. Eligible data were used to estimate prevalence via a Bayesian meta-regression tool (DisMod-MR 2.1). Modelled prevalence and disability weights were used to estimate health burden in years lived with disability (YLDs) as the measure of non-fatal health burden and disability-adjusted life-years (DALYs) as the measure of overall health burden. Data by ethnicity were not available. People with lived experience of autism were involved in the design, preparation, interpretation, and writing of this Article.FindingsAn estimated 61·8 million (95% uncertainty interval 52·1–72·7) individuals (one in every 127 people) were on the autism spectrum globally in 2021. The global age-standardised prevalence was 788·3 (663·8–927·2) per 100 000 people, equivalent to 1064·7 (898·5–1245·7) autistic males per 100 000 males and 508·1 (424·6–604·3) autistic females per 100 000 females. Autism spectrum disorder accounted for 11·5 million (7·8–16·3) DALYs, equivalent to 147·6 (100·2–208·2) DALYs per 100 000 people (age-standardised) globally. At the super-region level, age-standardised DALY rates ranged from 126·5 (86·0–178·0) per 100 000 people in southeast Asia, east Asia, and Oceania to 204·1 (140·7–284·7) per 100 000 people in the high-income super-region. DALYs were evident across the lifespan, emerging for children younger than age 5 years (169·2 [115·0–237·4] DALYs per 100 000 people) and decreasing with age (163·4 [110·6–229·8] DALYs per 100 000 people younger than 20 years and 137·7 [93·9–194·5] DALYs per 100 000 people aged 20 years and older). Autism spectrum disorder was ranked within the top-ten causes of non-fatal health burden for people younger than 20 years.InterpretationThe high prevalence and high rank for non-fatal health burden of autism spectrum disorder in people younger than 20 years underscore the importance of early detection and support to autistic young people and their caregivers globally. Work to improve the precision and global representation of our findings is required, starting with better global coverage of epidemiological data so that geographical variations can be better ascertained. The work presented here can guide future research efforts, and importantly, decisions concerning allocation of health services that better address the needs of all autistic individuals.FundingQueensland Health and the Bill & Melinda Gates Foundation.

Noonan syndrome (NS) is a RASopathy, a group of genetic disorders caused by alterations in the RAS/MAPK signalling pathway, and is associated with brain-related disorders, including intellectual developmental disorder (IDD), autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), epilepsy, and depression and anxiety. However, estimates of prior prevalence vary widely. The aim of this systematic review and meta-analysis was to estimate the prevalence of brain-related disorders (i.e., IDD, ASD, ADHD, epilepsy, and depression and anxiety) in NS. A systematic search of Medline, Scopus, Web of Science and the Cochrane Library was conducted from inception to July 2025. Studies that estimated the prevalence of IDD, ASD, ADHD, epilepsy, and depression and anxiety in the population with NS were included. Genotype was considered when possible. Random-effects meta-analyses of prevalence, expressed as proportions (0-1) and their 95% confidence intervals (95% CI), were performed. Twenty-one studies were included in the systematic review, while 20 were included in the meta-analysis. The IDD prevalence was 0.23 (95% CI: 0.12, 0.35), the ASD prevalence was 0.11 (95% CI: 0.05, 0.17); the ADHD prevalence was 0.31 (95% CI: 0.22, 0.41); the epilepsy prevalence was 0.09 (95% CI: 0.03, 0.15) and the depression and anxiety prevalence was 0.23 (95% CI: 0.08, 0.39). There was hardly any genotype-specific data, particularly for minor mutations. NS is strongly associated with brain-related disorders, which reinforces the need for early and periodic screening in this population. Furthermore, genotype-phenotype correlation studies are required, as there is currently little evidence in this area. What is Known: • Noonan syndrome is a RASopathy characterised by short stature, heart disease and brain-related disorders. • Brain-related disorders include intellectual developmental disorder (IDD), autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), among others. What is New: • IDD, ASD and ADHD were estimated to affect 23%, 11% and 31% of individuals, respectively. This is higher than the prevalence in the general population. • The prevalence of seizure disorders and emotional disorders was also high, although the evidence was more limited.

The UK prevalence of parent-reported autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) were estimated from the Millennium Cohort Study. Case definition was if a doctor or health care professional had ever told parents that their child had ASD and/or ADHD. Data were collected in 2008/2009 for 14,043 children. 1.7% of children were reported as having ASD (95% CI 1.4-2.0) at mean age 7.2years (SD=0.2; range=6.3-8.2). 1.4% reportedly had ADHD (95% CI 1.2-1.7), and 0.3% had both ASD and ADHD (95% CI 0.2-0.5). After adjusting for socio-economic disadvantage, only male sex (p<0.001 for both conditions) and cognitive ability, p=0.004 (ASD); p=0.01 (ADHD) remained strongly associated. The observed prevalence of parent-reported ASD is high compared to earlier UK and US estimates. Parent-reported ADHD is low compared to US estimates using the same measure.

The aim of this study was to explore the prevalence of attention deficit hyperactivity disorder (ADHD) and/or autism spectrum disorder (ASD) and its relation to lifestyle in female college students. A total of 375 female college students (19.2±1.3years) among 439 students were enrolled in this cross-sectional study. Using a self-reported questionnaire, we measured the prevalence of ADHD using the ADHD Self-Report Scale-v1.1 (ASRS) and the prevalence of ASD using the Autism-Spectrum Quotient (AQ). In addition, lifestyle choices such as medications, physical activity, cigarette smoking, alcohol drinking and sleeping habits were also evaluated. The suspected prevalence of ADHD was 102 students (27.2%) and the suspected prevalence of ASD was 4 students (1.1%). Only one student (0.3%) was thought to have both ADHD and ASD. Subjects with suspected ADHD had higher AQ scores compared with those without suspected ADHD. There were no unhealthy lifestyle choices in subjects with suspected ADHD and/or ASD. The prevalence of suspected ADHD and/or ASD may be relatively high even among female college students in Japan.