The prevalence of autism spectrum disorder (ASD) among children in the United States has risen dramatically over the past two decades. In 2022, an estimated 32.2 out of every 1,000 8-year-old children were identified with ASD, marking a nearly fivefold increase from the rate of 6.7 per 1,000 children in 2000. This significant upward trend underscores the growing importance of understanding and addressing ASD in American society. Gender disparities in autism diagnosis The increase in ASD prevalence is not uniform across genders. From 2016 to 2019, male children were nearly four times more likely to be diagnosed with ASD than their female counterparts. Approximately 4.8 percent of boys aged 3 to 17 years had received an ASD diagnosis at some point in their lives, compared to only 1.3 percent of girls in the same age group. This substantial gender gap highlights the need for further research into potential biological and social factors influencing ASD diagnosis rates. Racial and ethnic variations in autism prevalence Autism prevalence also varies across racial and ethnic groups. Data from 2016 to 2019 show that non-Hispanic white children aged 3 to 17 years had an ASD prevalence of 2.9 percent, while around 3.5 percent of Hispanic children had ASD. While this statistic provides insight, it is essential to consider potential disparities in diagnosis and access to services among different racial and ethnic communities. Further research and targeted interventions may be necessary to ensure equitable identification and support for children with ASD across all populations.

Structural variation is thought to play a major etiological role in the development of autism spectrum disorders (ASDs), and numerous studies documenting the relevance of copy number variants (CNVs) in ASD have been published since 2006. To determine if large ASD families harbor high-impact CNVs that may have broader impact in the general ASD population, we used the Affymetrix genome-wide human SNP array 6.0 to identify 153 putative autism-specific CNVs present in 55 individuals with ASD from 9 multiplex ASD pedigrees. To evaluate the actual prevalence of these CNVs as well as 185 CNVs reportedly associated with ASD from published studies many of which are insufficiently powered, we designed a custom Illumina array and used it to interrogate these CNVs in 3,000 ASD cases and 6,000 controls. Additional single nucleotide variants (SNVs) on the array identified 25 CNVs that we did not detect in our family studies at the standard SNP array resolution. After molecular validation, our results demonstrated that 15 CNVs identified in high-risk ASD families also were found in two or more ASD cases with odds ratios greater than 2.0, strengthening their support as ASD risk variants. In addition, of the 25 CNVs identified using SNV probes on our custom array, 9 also had odds ratios greater than 2.0, suggesting that these CNVs also are ASD risk variants. Eighteen of the validated CNVs have not been reported previously in individuals with ASD and three have only been observed once. Finally, we confirmed the association of 31 of 185 published ASD-associated CNVs in our dataset with odds ratios greater than 2.0, suggesting they may be of clinical relevance in the evaluation of children with ASDs. Taken together, these data provide strong support for the existence and application of high-impact CNVs in the clinical genetic evaluation of children with ASD.

This data collection is associated with a large population-based twin study of gender differences in autism. The data were collected from 2016-2019 from a sample population based in the UK. All participants were aged between 20-24 years of age at the time of data collection. The data deposited in this collection are taken from in-home assessments and accompanying questionnaires completed by the twins. The collection includes data from Autism Diagnostic Observation Schedule -2 assessments, the Social Responsiveness Scale (2nd edition) (a measure of autism traits), WASI IQ assessments, Strengths and Difficulties Questionnaire total domain scores (a measure of aspects of mental health) and the WHOQoL Bref (a measure of quality of life). Also included in the collection are demographic information for the participants including sex, age, zygosity and a grouping variable to indicate whether they were included in the study’s diagnosed, high trait or co-twin sample groups.

Introduction: This chapter presents the analysis of physician-diagnosed International Classification of Diseases (ICD version 9) disorders and diseases associated with autism spectrum disorders (ASD) in a 16-year pediatric cohort.Materials and Methods: The sample (n = 47,180; 62% male) consisted of children in the Alberta Health Services Calgary Health Region catchment under the age of 3 years, who received any physician-assigned ICD 9 diagnosis before the age of three between April 1993 and December 31, 1994. There were 111 females and 609 males with ASD diagnosed at any time between 1993 and 2010. The results detail the 16-year odds ratio (OR) associations of ASD diagnosis within the major classes of international classification of diseases (ICD 9) stratified by age and sex in the cohort. Further, for those suffering from ASD and any other disorder or disease, the analysis presents by sex, age, and duration, the proportions of all index physician-assigned ICD diagnoses, arising significantly before and after the index ASD diagnosis.Results: The rate of treated ASD in the cohort was 1 in 65 and the 16-year population rate of ASD was 62 per 10,000. For males with an ASD over the 16 year period, the ORs were significantly greater than the value one for 15 of the 17 main ICD classes and for 10 of the main ICD classes for females. Different age strata presented a more specific account of the main ICD class OR profiles. More specifically, 28 ICD disorders significantly preceded and 95 ICD disorders significantly followed ASD for females. Thirty-eight ICD disorders significantly preceded and 234 ICD disorders significantly followed ASD for males.Conclusions: The results largely confirm past studies focusing on more constrained sets of ASD morbidity. The age-stratified ORs gauge the order of risk in time for the cohort. The proportions of specific ICD disorders arising before and after ASD may be useful in respect to informing basic ASD research and ASD clinical management. Limitations are discussed.

The prevalence rate of autism spectrum disorder among children aged eight years in the state Georgia was estimated to be around **** per 1,000 children. Autism spectrum disorder is a developmental disability characterized by deficits in social communication and interaction as well as repetitive behavior, interest, or activity patterns. Autism spectrum disorder in childrenAmong 14 U.S. states with areas that were monitored for autism spectrum disorder in 2022, California had the highest prevalence rates of autism spectrum disorder (ASD) among children aged eight years. In 2022, California’s prevalence rate was estimated to be **** cases per 1,000 children, while the rate was about **** cases per 1,000 children in Indiana. ASD is more common among male than female children, with an estimated ** male cases per 1,000 children and ** female cases per 1,000 children in California in 2022. Limitations in a child with autism can vary between individuals and develop over time. In California, the median age of diagnosis among children with an ASD diagnosis with an IQ greater than 70 was ********* of age, in comparison to ********* for children with an ASD diagnosis and an IQ less than or equal to 70, indicating a co-occurring intellectual disability. The prevalence of ASD has increased significantly since the late 1960s by about ** to ** times. Many studies suggest that this is due to improved awareness and recognition, as well as diagnostic capabilities. Autism is likely caused by a combination of genetics and environmental factors, where people with ASD may have abnormal levels of brain serotonin, which could disrupt early brain development.

Dataset from manuscript titled "Implementing an early detection program for autism spectrum disorders in Polish primary healthcare setting – possible obstacles and experiences from online ASD screening"

The global Autism Spectrum Disorder (ASD) market, valued at $7.78 billion in 2025, is projected to experience robust growth, exhibiting a Compound Annual Growth Rate (CAGR) of 7.6% from 2025 to 2033. This expansion is driven by several key factors. Increased awareness and early diagnosis of ASD are leading to higher treatment rates. Advances in therapeutic interventions, including both pharmacological and non-pharmacological approaches, offer improved outcomes for individuals with ASD and their families. Furthermore, the growing prevalence of ASD globally, coupled with increased investment in research and development of new treatments, fuels market growth. The market is segmented by therapy type (pharmacological and non-pharmacological) and age group (pediatric and adult), reflecting the diverse needs of the ASD population. Pharmacological therapies currently hold a larger market share, due to the established efficacy of certain medications in managing ASD-related symptoms. However, the non-pharmacological segment is experiencing significant growth, driven by rising interest in behavioral therapies and other holistic approaches. The adult segment shows increasing demand as individuals with ASD live longer and require continued support. Regionally, North America and Europe currently dominate the market due to established healthcare infrastructure, higher awareness, and greater access to specialized services. However, Asia-Pacific is expected to witness significant growth in the coming years, fueled by rising disposable incomes, improved healthcare access, and increasing diagnostic capabilities. Competitive pressures within the market are intense, with leading companies focusing on developing innovative therapies, expanding their geographical reach, and strengthening their market positioning through strategic collaborations and acquisitions. Challenges remain, including the high cost of treatments, accessibility issues in certain regions, and the need for more effective treatments for specific ASD-related symptoms. Despite these challenges, the long-term outlook for the ASD market remains positive, driven by sustained investment in research, growing awareness, and an increasing focus on improving the lives of individuals with ASD.

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Autism Spectrum Disorder Therapeutics Market Size 2025-2029

The autism spectrum disorder therapeutics market size is forecast to increase by USD 825.9 million at a CAGR of 6.9% between 2024 and 2029.

The Autism Spectrum Disorder (ASD) therapeutics market is experiencing significant growth due to the increasing prevalence of ASD, with an estimated 1 in 54 children diagnosed with the disorder in the United States alone. This trend is driven by heightened awareness, improved diagnostic tools, and expanding healthcare coverage. Another key driver is the growing interest in personalized medicine for ASD treatment, as researchers explore the potential of precision therapies tailored to individual patients' unique genetic and environmental factors. This market is driven by the growing awareness and early diagnosis of ASD, fueled by increasing public education and advancements in genetic research and genetic testing. 
Additionally, the complex nature of ASD and its diverse symptoms necessitate a multidisciplinary approach, adding to the development challenges and costs. Companies seeking to capitalize on market opportunities must navigate these regulatory hurdles and collaborate with various stakeholders to develop effective, personalized treatment solutions for the ASD population. However, the market faces several challenges. However, the market is also subject to stringent regulations, ensuring the safety and efficacy of therapeutic interventions and medical technologies.

What will be the Size of the Autism Spectrum Disorder Therapeutics Market during the forecast period?

Explore in-depth regional segment analysis with market size data - historical 2019-2023 and forecasts 2025-2029 - in the full report.
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The Autism Spectrum Disorder (ASD) therapeutics market encompasses a range of interventions addressing the neurological underpinnings and diverse manifestations of this complex condition. Cognitive impairment, executive function deficits, emotional regulation skills, and sensory processing disorders are common challenges for individuals with ASD. Sleep hygiene practices and mental health services are essential components of holistic care, with growing emphasis on community integration and supported employment. Pharmacological treatments, including those targeting anxiety reduction and depression management, are used in conjunction with behavioral interventions such as Applied Behavior Analysis (ABA) therapy methods and communication intervention. Genetic screening and diagnostic tools are crucial for early childhood intervention, while teacher training and inclusionary educational practices foster a more comprehensive understanding of ASD subtypes.

Neuronal circuit dysfunction and immune system involvement are areas of ongoing research, with brain imaging techniques providing valuable insights into the condition's neurological basis. Self-harm prevention strategies and adaptive behavior skills training are essential for promoting independence and improving quality of life. CBT for autism and vocational rehabilitation programs further enhance the overall therapeutic landscape. Autism prevalence rates continue to rise, necessitating a multifaceted, evidence-based approach to addressing the diverse needs of this population. Antipsychotic drugs, including bipolar disorder therapeutics, are commonly prescribed for managing aggressive behaviors, mood stabilization, and anxiety in ASD patients.

How is this Autism Spectrum Disorder Therapeutics Industry segmented?

The autism spectrum disorder therapeutics industry research report provides comprehensive data (region-wise segment analysis), with forecasts and estimates in 'USD million' for the period 2025-2029, as well as historical data from 2019-2023 for the following segments.

Distribution Channel

  Retail pharmacy
  Hospital pharmacy
  Online pharmacy


Type

  Stimulants
  Selective serotonin reuptake inhibitors
  Antipsychotic drugs
  Sleep medications
  Others


Application

  Autistic disorder
  Asperger syndrome
  Pervasive developmental disorder
  Others


Geography

  North America

    US
    Canada


  Europe

    France
    Germany
    Italy
    Spain
    UK


  APAC

    China
    India
    Japan


  Rest of World (ROW)

By Distribution Channel Insights

The Retail pharmacy segment is estimated to witness significant growth during the forecast period. The autism spectrum disorder (ASD) therapeutics market is experiencing significant growth due to increasing awareness and advancements in novel treatment approaches. Cognitive behavioral therapy, occupational therapy interventions, and neurobiological mechanisms form the foundation of many interventions, addressing social skills training, communication deficits, sensory integration, and emotional regulation. Family therapy approaches and educational support services are essential

This statistic displays the prevalence rate of autism spectrum disorders in Italy from 2010 to 2017. According to data, the rate slightly decreased over the period of consideration. As of 2017, among the Italian population about *** out of 100,000 individuals suffered from some autism spectrum disorder.

This statistic shows the prevalence rate of autism spectrum disorders in Italy in 2017, by age group. According to the estimates, in the age group including kids aged five to nine roughly *** children out of 100,000 population, were suffering from autism spectrum disorders.

This dataset is no longer updated as of April 2023.

Basic Metadata Note: Condition is a new addition to 2017. *Rates per 100,000 population. Age-adjusted rates per 100,000 2000 US standard population.

**Blank Cells: Rates not calculated for fewer than 5 events. Rates not calculated in cases where zip code is unknown.

***API: Asian/Pacific Islander. ***AIAN: American Indian/Alaska Native.

Prepared by: County of San Diego, Health & Human Services Agency, Public Health Services, Community Health Statistics Unit, 2019.

Code Source: ICD-9CM - AHRQ HCUP CCS v2015. ICD-10CM - AHRQ HCUP CCS v2018. ICD-10 Mortality - California Department of Public Health, Group Cause of Death Codes 2013; NHCS ICD-10 2e-v1 2017.

Data Guide, Dictionary, and Codebook: https://www.sandiegocounty.gov/content/dam/sdc/hhsa/programs/phs/CHS/Community%20Profiles/Public%20Health%20Services%20Codebook_Data%20Guide_Metadata_10.2.19.xlsx

BackgroundThe Sustainable Development Goals (SDGs) call for systematic monitoring to optimize child development outcomes. As a developmental disorder affecting children and adults, Autism Spectrum Disorder (ASD) not only impacts individual social functioning but also places a burden on families and society. A detailed analysis of the latest global burden data on ASD can assist stakeholders in formulating support policies and interventions, thereby helping to meet the health needs of ASD.MethodsWe used data from the Global Burden of Disease Study 2021 (GBD 2021), compiled by the Institute for Health Metrics and Evaluation (IHME). Data were obtained through the Global Health Data Exchange (GHDx) and covered 204 countries and territories from 1990 to 2019. Variables included ASD-related prevalence, mortality, disability-adjusted life years (DALYs), age-standardized rates, and the sociodemographic index (SDI).ResultsExposure to autism spectrum disorders contributed to 61823540 prevalence and 11544038 DALYs globally in 2021. Males and younger adults were high-risk populations. Higher socio-demographic index (SDI) regions were high-risk areas. The disease burden varied considerably across the GBD regions and the countries. From 1990 to 2021, the number of cases increased. The predicted results showed that the disease burden for both genders would still increase from 2022 to 2046. Countries or regions with a higher SDI have greater burden improvement potential.ConclusionThe global burden of ASD has shown a continuous upward trend, with some differences observed across gender, age groups, and SDI regions. In terms of gender, the burden of ASD among females may be underestimated. Regarding age groups, the aging process has highlighted the urgent need to address ASD in the elderly population. High-SDI regions should place greater emphasis on improving diagnostic methods and implementing precise interventions, while middle- and low-SDI regions should focus on raising public awareness and enhancing screening capabilities.

Counts given for patients in the pediatric and general hospital(s), and their sum. All counts are for patients under age 35.

This dataset contains Symptomatic data for Autism Spectrum Disorder (ASD) collected using M-CHAT-R. The data was gathered from parents of children aged from 3 to 15 years in North Cairo Governorate, Egypt across multiple institutions:Ain Shams Center for Special Needs CareThe Egyptian Autism SocietyResala Charity OrganizationDirect interviews with parents via social media "WhatsApp, Facebook".The main purpose of this dataset is to support autism research, and machine learning applications by providing real data in an Arabic-speaking population.

Background: Of all the childhood vaccines, the measles-mumps-rubella (MMR) vaccination has a uniquely controversial history. The present study aimed to investigate whether attitudes to autism spectrum disorders (ASD) and the ability to appropriately interpret scientific information impacts parental decisions regarding vaccination. Method: A sample of 132 parents and expectant parents (mean age 38.40 years; > 60% with university education) participated in a survey related to attitudes toward and knowledge about the MMR and ASD, and completed a standardized test of science (The American College Test). Results: Knowledge of ASD was related to attitudes towards ASD while attitudes towards ASD were related to scientific literacy and attitudes towards MMR. Only attitudes towards MMR predicted MMR vaccine status (i.e., vaccination decision). Conclusion: Factors other than scientific literacy seem to contribute towards MMR vaccine status.

Providing eyewitness testimony involves monitoring one’s memory to provide a detailed and accurate account: reporting details likely to be accurate and withholding potentially inaccurate details. Autistic individuals reportedly experience difficulties in both retrieving episodic memories and monitoring their accuracy, which has important implications for eyewitness testimony. Thirty autistic and 33 IQ-matched typically developing (TD) participants viewed a video of a mock bank robbery followed by three phases of questions (with judgments of confidence). In Phase 1, participants freely generated the granularity of their responses (i.e., fine- or coarse-grained). In Phase 2, participants answered the same questions but provided both a fine- and a coarse-grained answer. In Phase 3, participants were instructed to maximise accuracy over informativeness by selecting one of their Phase 2 answers as their final answer. They either received the questions socially (from the experimenter) or answered them online. There were no group differences in accuracy or metacognitive monitoring, with both autistic and TD witnesses demonstrating: a) a strong preference for reporting fine-grained details at the expense of accuracy; b) improved, though still sub-optimal grain size reporting when instructed to maximise accuracy over informativeness; c) effective accuracy monitoring; and d) higher overall accuracy when questions were delivered socially. There was, however, a subtle difference in metacognitive control, with autistic witnesses performing more poorly than TD witnesses when questions were delivered socially, but not when they were delivered online. These findings contrast with evidence suggesting that autism is marked by impairments in episodic memory and metacognitive monitoring and control. Autism spectrum disorder (ASD) is diagnosed in around 1% of the population and presents a number of challenges to the day-to-day lives of these individuals as well as their families and support services. This project will provide an evidence base and guide improvements to existing methods used by professional groups to support those with ASD. This will take place in three important information-gathering contexts in which they are currently at a disadvantage. First, only around half of young adults with ASD have worked for pay outside the home - the lowest rate among disability groups. Performance in occupational interviews is a crucial determinant of employment prospects, yet the social, cognitive and communication difficulties of ASD mean they are often unable to perform to the best of their abilities in interviews. Second, people with ASD are more likely to have certain social and health-related issues and co-occurring conditions, and may therefore be more likely to visit health and social care professionals. However, difficulties with introspection and social communication are likely to make relaying relevant information difficult, unless their specific difficulties are appropriately supported. Finally, although individuals with ASD are over-represented in the Criminal Justice System (CJS) as both witnesses (victims) and suspects, current police interviewing models are ineffective in supporting them to provide 'best evidence'. For people with ASD and their families, research on societal issues and improving the lives of ASD individuals is vital. Yet research of this nature is currently lacking. Most services including health and social care, employment and the justice system are developed to cater for "neurotypical" people, or adapted for those with broad intellectual disability. However little consideration or support is in place for the social and cognitive difficulties that are specific to ASD. If individuals with ASD are to receive appropriate and fair access to services and justice, their difficulties must be better understood and accommodated. This begins with their reporting of relevant information to authorities and services. People with ASD show impairments in socio-cognitive domains, including a lack of insight into their own and others' intentions, as well as 'executive functions' (a set of capacities involving cognitive control, regulation, planning and flexibility). As a result, they experience problems in open-ended social situations where the desired response or type of information required from them needs to be inferred. The proposed project will compare how individuals with and without ASD perform on varying social and open-ended tasks. It builds on my existing work to test 1) how the shifting social contexts and increased task complexity inherent in information-gathering interactions in employment, healthcare and CJS contexts might heighten ASD impairments, and 2) how these can be ameliorated with appropriate support. Furthermore, people with ASD can also have areas of strength, and the research aims to determine how these strengths can be utilised to develop interviewing formats that support their difficulties whilst capitalising on their strengths. This research will directly inform best practice in HR, health and social care and the CJS, improving access to services and justice for people with ASD. It will also advance theory by providing new insight into how the social and cognitive difficulties (and strengths) of ASD impact upon real life social interactions. Findings will have implications for national organisations, including the Department of Health, Department for Business Innovation and Skills, Home Office, as well as more local groups, for example, potential employers, police interviewers and health and social care professionals. An extensive program of dissemination to both academic and non-academic stakeholders is planned to maximise the research impact with a broad range of key users. A total of 63 participants took part: 30 autistic adults (16 males, 14 females) and 33 age- and IQ-matched typically developed (TD) participants (7 males; 26 females). Participants were recruited mainly from the South West of England and surrounding areas, including via previous research participation, autism-related and local community Facebook groups, social and support groups, as well as via local community recruitment (including posters, magazine articles, and social media posts, and University website campaigns). All autistic participants had received a formal clinical diagnosis of Autism Spectrum Disorder according to DSM–IV (American Psychiatric Association, 2000) or DSM-5 criteria (American Psychiatric Association, 2013), and confirmed this with a copy of their clinical diagnostic report. Six participants had received a clinical diagnosis but were unable to access their report and were therefore administered the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2; Lord et al., 2012) to confirm their diagnoses. Participants provided their written informed consent to take part and were fully debriefed. Ethical approval was obtained from the Psychology Research Ethics Committee at the University of Bath. Participants individually viewed a video of a mock bank robbery followed by three phases of questions (with judgments of confidence). In Phase 1, participants freely generated the granularity of their responses (i.e., fine- or coarse-grained). In Phase 2, participants answered the same questions but provided both a fine- and a coarse-grained answer. In Phase 3, participants were instructed to maximise accuracy over informativeness by selecting one of their Phase 2 answers as their final answer. They either received the questions socially (from the experimenter) or answered them online.

The global market for Autism Spectrum Disorder (ASD) treatment is experiencing significant growth, projected to reach $3.142 billion in 2025 and maintain a Compound Annual Growth Rate (CAGR) of 4.5% from 2025 to 2033. This substantial expansion is driven by several factors. Increasing prevalence of ASD diagnoses globally, coupled with heightened awareness and improved diagnostic capabilities, fuels demand for effective therapies. Furthermore, advancements in research and development are leading to the introduction of innovative treatments, including behavioral therapies, medication, and assistive technologies. The market's growth is also influenced by supportive government initiatives and insurance coverage expansions that facilitate access to treatment for a wider population. The competitive landscape involves a diverse range of pharmaceutical companies and healthcare providers, including Curemark, LLC, Alembic Pharmaceuticals Limited, and Roche Holding AG, contributing to the market’s dynamism and ongoing innovation. The continued expansion of the ASD treatment market is expected to be influenced by evolving treatment paradigms, focusing on early intervention and personalized care approaches. Growing research into the underlying neurological mechanisms of ASD is paving the way for more targeted therapies. While challenges remain, such as variations in treatment access across different geographical regions and the high cost of certain therapies, the overall market outlook remains positive. The ongoing development of new drugs and therapies targeting specific ASD symptoms and the increasing adoption of digital health solutions for monitoring and managing ASD will further accelerate market expansion over the forecast period. The market’s segmentation is likely to further evolve, with specialized treatment options emerging for specific subgroups within the ASD spectrum.

Autism spectrum disorder (ASD) prevalence per 1,000 children (with 95% confidence interval) for 2010 Georgia Autism and Developmental Disabilities Monitoring Network site: comparison between published and algorithm-derived estimates.

The global market for the diagnosis and treatment of Autism Spectrum Disorder (ASD) is experiencing robust growth, driven by increasing prevalence rates, heightened awareness, and advancements in diagnostic tools and therapeutic interventions. The market's expansion is fueled by a rising number of diagnosed cases worldwide, particularly in developed nations with advanced healthcare infrastructure and greater access to specialized services. Further propelling growth are ongoing research efforts focused on developing innovative therapies, including behavioral interventions, medication, and assistive technologies, aiming to improve the quality of life for individuals with ASD and their families. While the exact market size for 2025 is unavailable, considering a plausible CAGR of 8% (a conservative estimate given market dynamics) and a potential 2024 market size of $15 billion (estimated based on available data and market trends in related therapeutic areas), the 2025 market size could be conservatively projected around $16.2 billion. This figure is likely to increase significantly by 2033, reflecting the ongoing market expansion. Significant regional variations exist, with North America and Europe currently holding the largest market shares due to higher healthcare expenditure, advanced diagnostic capabilities, and established healthcare infrastructure. However, the Asia-Pacific region is poised for considerable growth, driven by increasing awareness, improving healthcare infrastructure, and a growing population. Market segmentation reveals substantial opportunities in both the hospital and clinic settings, with a notable increase in demand for personalized interventions tailored to individual needs and age groups (adult vs. child). The market faces certain challenges, such as high treatment costs, limited availability of skilled professionals, and varying levels of awareness in different regions. However, these are being addressed through government initiatives promoting early diagnosis, improving access to affordable care, and investment in research and development of new therapies.

Both Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are neurodevelopmental conditions with a majority of affected males ranging from a ratio of 4:1 to 3:1 for ASD (Loomes, Hull, and Mandy 2017; Dalsgaard et al. 2020), and around 3:1 to 2:1 for ADHD (Dalsgaard et al. 2020). In both conditions, females tend to be diagnosed later than males (Dalsgaard et al. 2020; Mowlem et al. 2019), which might have serious long-term consequences for the mental health of girls. The later diagnosis in females may be related to sex differences in how ASD and ADHD are expressed, as girls tend to display more subtle, but equally impairing, symptoms of ASD and ADHD (Lai et al. 2015; Loyer Carbonneau et al. 2021). School-aged boys with ASD tend to display more overt autism symptoms than girls with ASD within the domains of social-communication problems as well as repetitive behaviours (Hiller, Young, and Weber 2014 et al. 2014, Sedgewick et al. 2015; Hiller R, 2017), while girls with ASD may display more masking behaviours (Head, McGillivray, and Stokes 2014). Similarly, school-aged girls with ADHD may show fewer overt symptoms of hyperactivity and impulsivity relative to boys with ADHD, which may be related to a stronger tendency for girls relative to boys to internalize their mental health problems (Ochoa-Lubinoff, Makol, and Dillon 2023; Loyer Carbonneau et al. 2021). However, it is essentially unknown if there are sex differences already present in infancy in ASD and ADHD. Early markers of neurodevelopmental disorders in the first year of life, such as deviations in the acquisition of developmental milestones, have been reported in both ASD and ADHD (Johnson et al. 2015). The early markers include abnormalities in socio-emotional development such as poorer vocalisations, gestures and social engagement in ASD (Dawson, Rieder, and Johnson 2023), and problems sustaining attention during play in ADHD (Joseph et al. 2023), and increased problems with physiological regulatory processes in both conditions (Johnson et al. 2015; Barnevik Olsson et al. 2013; Hemmi, Wolke, and Schneider 2011). A recent retrospective and cross-sectional study found that parents of girls with ASD had experienced early concerns about delayed motor development, while parents of autistic boys recalled having early concerns about delayed language (Dillon et al. 2023). To our knowledge, no such studies have been conducted on ADHD. Hence, there is a lack of longitudinal population studies exploring whether there are sex-specific associations between infancy socio-emotional, motor, and regulatory problems with the risk and timing of getting a clinical diagnosis of ASD and ADHD. The Copenhagen Child Cohort 2000 (CCC2000) is a prospective longitudinal study following a large birth cohort of 6.090 children born in Copenhagen municipality in the year 2000. Children were followed from birth onwards, which repeated measurements of mental health and psychopathology. The health examinations by health nurses in the first year of life included standardized assessments of milestones acquisition across several domains of development such as socio-emotional, motor development and physiological regulatory processes. Moreover, the linking of data drawn from the Danish national registries allow us to track the course and outcome for every individual including the time to a first diagnosis of ASD and/or ADHD up until age 21. We will utilize the CCC2000 database to investigate sex differences in the early developmental antecedents of a diagnosis of ASD and/or ADHD.