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Autism Research : Official Journal of... May 2022Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we... (Review)
Review
Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we synthesized estimates of the prevalence of autism worldwide. We examined factors accounting for variability in estimates and critically reviewed evidence relevant for hypotheses about biological or social determinants (viz., biological sex, sociodemographic status, ethnicity/race, and nativity) potentially modifying prevalence estimates of autism. We performed the search in November 2021 within Medline for studies estimating autism prevalence, published since our last systematic review in 2012. Data were extracted by two independent researchers. Since 2012, 99 estimates from 71 studies were published indicating a global autism prevalence that ranges within and across regions, with a median prevalence of 100/10,000 (range: 1.09/10,000 to 436.0/10,000). The median male-to-female ratio was 4.2. The median percentage of autism cases with co-occurring intellectual disability was 33.0%. Estimates varied, likely reflecting complex and dynamic interactions between patterns of community awareness, service capacity, help seeking, and sociodemographic factors. A limitation of this review is that synthesizing methodological features precludes a quality appraisal of studies. Our findings reveal an increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity. Hypotheses linking factors that increase the likelihood of developing autism with variations in prevalence will require research with large, representative samples and comparable autism diagnostic criteria and case-finding methods in diverse world regions over time. LAY SUMMARY: We reviewed studies of the prevalence of autism worldwide, considering the impact of geographic, ethnic, and socioeconomic factors on prevalence estimates. Approximately 1/100 children are diagnosed with autism spectrum disorder around the world. Prevalence estimates increased over time and varied greatly within and across sociodemographic groups. These findings reflect changes in the definition of autism and differences in the methodology and contexts of prevalence studies.
Topics: Autism Spectrum Disorder; Autistic Disorder; Child; Ethnicity; Female; Humans; Male; Population Surveillance; Prevalence
PubMed: 35238171
DOI: 10.1002/aur.2696 -
Autism Research : Official Journal of... Mar 2022Autism spectrum disorder (ASD) and schizophrenia (SCZ) are separate disorders, with distinct clinical profiles and natural histories. ASD, typically diagnosed in... (Review)
Review
Autism spectrum disorder (ASD) and schizophrenia (SCZ) are separate disorders, with distinct clinical profiles and natural histories. ASD, typically diagnosed in childhood, is characterized by restricted or repetitive interests or behaviors and impaired social communication, and it tends to have a stable course. SCZ, typically diagnosed in adolescence or adulthood, is characterized by hallucinations and delusions, and tends to be associated with declining function. However, youth with ASD are three to six times more likely to develop SCZ than their neurotypical counterparts, and increasingly, research has shown that ASD and SCZ converge at several levels. We conducted a systematic review of studies since 2013 relevant to understanding this convergence, and present here a narrative synthesis of key findings, which we have organized into four broad categories: symptoms and behavior, perception and cognition, biomarkers, and genetic and environmental risk. We then discuss opportunities for future research into the phenomenology and neurobiology of overlap between ASD and SCZ. Understanding this overlap will allow for researchers, and eventually clinicians, to understand the factors that may make a child with ASD vulnerable to developing SCZ. LAY SUMMARY: Autism spectrum disorder and schizophrenia are distinct diagnoses, but people with autism and people with schizophrena share several characteristics. We review recent studies that have examined these areas of overlap, and discuss the kinds of studies we will need to better understand how these disorders are related. Understanding this will be important to help us identify which autistic children are at risk of developing schizophrenia.
Topics: Adolescent; Adult; Autism Spectrum Disorder; Autistic Disorder; Child; Communication; Humans; Schizophrenia
PubMed: 34967130
DOI: 10.1002/aur.2659 -
The Lancet. Psychiatry Oct 2019Co-occurring mental health or psychiatric conditions are common in autism, impairing quality of life. Reported prevalences of co-occurring mental health or psychiatric... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Co-occurring mental health or psychiatric conditions are common in autism, impairing quality of life. Reported prevalences of co-occurring mental health or psychiatric conditions in people with autism range widely. Improved prevalence estimates and identification of moderators are needed to enhance recognition and care, and to guide future research.
METHODS
In this systematic review and meta-analysis, we searched MEDLINE, Embase, PsycINFO, Scopus, Web of Science, and grey literature for publications between Jan 1, 1993, and Feb 1, 2019, in English or French, that reported original research using an observational design on the prevalence of co-occurring mental health conditions in people with autism and reported confirmed clinical diagnoses of the co-occurring conditions and autism using DSM or ICD criteria. For co-occurring mental health conditions reported with at least 15 datapoints (studies), we assessed risk of bias and we determined pooled estimates of prevalence for different co-occurring conditions in autism using random-effects models, and descriptively compared these with prevalence estimates for the general population from the literature (post hoc). We investigated heterogeneity in prevalence estimates using random-effects meta-regression models. This systematic review is registered with PROSPERO, CRD42018103176.
FINDINGS
Of 9746 unique studies identified, 432 were selected for full-text review. 100 studies were eligible for inclusion in our qualitative synthesis, of which 96 were included in our meta-analyses. 11 categories of co-occurring conditions were investigated, of which eight conditions were included in the meta-analyses and three were descriptively synthesised (ie, trauma and stressor-related disorders, substance-related and addictive disorders, and gender dysphoria). From our meta-analyses, we found overall pooled prevalence estimates of 28% (95% CI 25-32) for attention-deficit hyperactivity disorder; 20% (17-23) for anxiety disorders; 13% (9-17) for sleep-wake disorders; 12% (10-15) for disruptive, impulse-control, and conduct disorders; 11% (9-13) for depressive disorders; 9% (7-10) for obsessive-compulsive disorder; 5% (3-6) for bipolar disorders; and 4% (3-5) for schizophrenia spectrum disorders. Estimates in clinical sample-based studies were higher than in population-based and registry-based studies, and these estimates were mostly higher than those in the general population (post hoc). Age, gender, intellectual functioning, and country of study were associated with heterogeneity in prevalence estimates, yet remaining heterogeneity not explained was still substantial (all I >95%).
INTERPRETATION
Co-occurring mental health conditions are more prevalent in the autism population than in the general population. Careful assessment of mental health is an essential component of care for all people on the autism spectrum and should be integrated into clinical practice.
FUNDING
Academic Scholars Awards, Department of Psychiatry, University of Toronto; O'Brien Scholars Program, Slaight Family Child and Youth Mental Health Innovation Fund, and The Catherine and Maxwell Meighen Foundation via the Centre for Addiction and Mental Health Foundation.
Topics: Autistic Disorder; Comorbidity; Humans; Mental Disorders; Prevalence
PubMed: 31447415
DOI: 10.1016/S2215-0366(19)30289-5 -
Autism Research : Official Journal of... Jan 2019Sensory integration is one of the most highly utilized interventions in autism, however, a lack of consensus exists regarding its evidence base. An increasing number of...
Sensory integration is one of the most highly utilized interventions in autism, however, a lack of consensus exists regarding its evidence base. An increasing number of studies are investigating the effectiveness of this approach. This study used the Council for Exceptional Children (CEC) Standards for Evidence-based Practices in Special Education to evaluate the effectiveness research from 2006 to 2017 on Ayres Sensory Integration (ASI) intervention for children with autism. A systematic review was conducted in three stages. Stage 1 involved an extensive database search for relevant studies using search terms related to sensory integration and autism, interventions suggesting a sensory integration approach, and high-quality study designs. Searches yielded 19 studies that were evaluated in Stage 2. Six of these met inclusion criteria of being peer-reviewed, written in English, description of intervention this is consistent with ASI intervention, and comparison group design or single subject method employed. Prior to analysis using CEC standards, three articles were excluded because intervention details were not consistent with the core principles of ASI, or because of major methodological flaws. In Stage 3, the remaining three studies were rated using the CEC quality indicators and standards for an evidence-based practice. Two randomized controlled trials respectively met 100% and 85% of the CEC criteria items. One additional study met more than 50% of the criteria. Based on CEC criteria, ASI can be considered an evidence-based practice for children with autism ages 4-12 years old. Autism Research 2019, 12: 6-19. © 2018 The Authors. Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc. LAY SUMMARY: Ayres Sensory Integration intervention is one of the most frequently requested and highly utilized interventions in autism. This intervention has specific requirements for therapist qualifications and the process of therapy. This systematic review of studies providing Ayres Sensory Integration therapy to children with autism indicates that it is an evidence-based practice according to the criteria of the Council for Exceptional Children.
Topics: Autistic Disorder; Child; Child, Preschool; Female; Humans; Occupational Therapy; Perception; Sensation; Sensation Disorders; Treatment Outcome
PubMed: 30548827
DOI: 10.1002/aur.2046 -
Arquivos de Neuro-psiquiatria Jun 2022The diagnosis of autism spectrum disorder (ASD) in Down syndrome (DS) is underestimated because it is necessary to understand which aspects of the behavioral phenotype...
The diagnosis of autism spectrum disorder (ASD) in Down syndrome (DS) is underestimated because it is necessary to understand which aspects of the behavioral phenotype are related to DS and which are related to ASD. Objective: To conduct a systematic review of the literature on early identification and diagnosis of ASD in patients with DS. Data source: The VHL, MEDLINE, Cochrane, CINAHL, Scopus, Web of Science and Embase databases were searched and data were evaluated using PRISMA. Data synthesis: Out of 1,729 articles evaluated, 15 were selected. Although well studied, identification of ASD in DS can be difficult because of the need to understand which aspects of the behavioral phenotype are related to Down syndrome and which to autism. In this review, the prevalence of ASD was found to range from 12% to 41%. Early identification of autism risk in individuals with Down syndrome is still poorly studied, even though there are screening instruments for infants. Several instruments for diagnosing autism in individuals with Down syndrome were found, but a developmental approach is fundamental for making a clear diagnosis. Conclusions: Screening procedures are important for detecting early signs of autism risk in the first year of life. Careful evaluation methods are needed to establish the diagnosis, which include choosing appropriate tools for evaluation of development and cognition, and analysis of qualitative aspects of social interaction, among others. It has been indicated in the literature that early detection and timely accurate diagnosis, in association with an intervention, may benefit development, quality of life and social inclusion.
Topics: Autism Spectrum Disorder; Autistic Disorder; Down Syndrome; Early Diagnosis; Humans; Quality of Life
PubMed: 35946706
DOI: 10.1590/0004-282X-ANP-2021-0156 -
Revista Medica Del Instituto Mexicano... 2017Autism spectrum disorder (ASD) was described for the first time in 1943 by Leo Kanner, and since 2004, 18 490 articles in the subject have been published, which in turn... (Review)
Review
Autism spectrum disorder (ASD) was described for the first time in 1943 by Leo Kanner, and since 2004, 18 490 articles in the subject have been published, which in turn have been cited 48 416 times.1 Almost half of these publications come from the United States of America and the vast maority of the efforts to improve the quality of life of these patients have taken place in developed countries. This disorder consists of an inability to acquire social and emotional skills during early development that progressively results in variable degrees of social adaptation discapacity. The etiology is multifactorial and includes functional and structural neurological abnormalities, some of them with putative genetic and/or epigenetic origin. There is an alarming lack of knowledge in the subject among health care professionals. The purpose of this systematic review is to summarize the most relevant historical, diagnostic and therapeutic aspects of ASD.
Topics: Autism Spectrum Disorder; Central Nervous System Agents; Combined Modality Therapy; Early Intervention, Educational; Humans; Mexico; Prognosis; Psychotherapy; Risk Factors
PubMed: 28296371
DOI: No ID Found -
Journal of Autism and Developmental... Oct 2017This systematic mapping review mapped current knowledge of equine-assisted interventions for people with autism to help guide future practice and research. Thirty-three... (Review)
Review
This systematic mapping review mapped current knowledge of equine-assisted interventions for people with autism to help guide future practice and research. Thirty-three studies including children and adolescents with autism, 3 of which confirmed diagnoses, were reviewed. Five types of equine-assisted activities were identified across 25 studies, with reported improvements in behavior, social interaction, and communication. Four types of equine-assisted therapies were identified across 8 studies, with reported improvements in motor control and self-care. Different approaches to therapeutic riding and hippotherapy, the most studied interventions, were evident. While this literature reflected early scientific development, it offered broad proof of concept that equine-assisted interventions can benefit children and adolescents with autism. Promising outcomes support continued investigation focused on standardization, appropriateness, and efficacy.
Topics: Adolescent; Animals; Autistic Disorder; Child; Communication; Equine-Assisted Therapy; Horses; Humans; Self Care
PubMed: 28733851
DOI: 10.1007/s10803-017-3219-9 -
Psychiatry Research May 2023Transidentity and autism frequently co-occur. Previous reviews have focused mainly on frequencies. Here, we conducted a systematic review to condense all the studies and... (Review)
Review
Transidentity and autism frequently co-occur. Previous reviews have focused mainly on frequencies. Here, we conducted a systematic review to condense all the studies and themes on this co-occurrence and to offer a global view. We followed the PRISMA method and selected 77 articles (including 59 clinical studies) in April 2022. We found 5 main themes (sex ratio, theories, sexual orientation, clinical and social consequences, and care implications) in addition to frequencies. Many theories have been proposed to explain the co-occurrence. One posits that social difficulties related to autism would lead to less identification with gender norms and less pressure to conform to these norms, allowing for greater gender diversity in people with autism. Given their difficulties with social interactions and communication, the announcement of one's transidentity to one's social group is often discredited, increasing the risk of suffering and delayed care. Many reports reaffirm the importance of providing specialised care for transgender people with autism. Autism is not a contraindication for gender-affirming treatment. However, some cognitive specificities can affect the planning of care, and transgender people with autism are at high risk of discrimination and harassment. We conclude that there is a need to raise awareness about gender and autism.
Topics: Humans; Male; Female; Autism Spectrum Disorder; Gender Dysphoria; Gender Identity; Transgender Persons; Sexual Behavior
PubMed: 36996732
DOI: 10.1016/j.psychres.2023.115176 -
Clinical Psychology Review Nov 2021Some autistic people employ strategies and behaviours to cope with the everyday social world, thereby 'camouflaging' their autistic differences and difficulties. This... (Review)
Review
Some autistic people employ strategies and behaviours to cope with the everyday social world, thereby 'camouflaging' their autistic differences and difficulties. This review aimed to systematically appraise and synthesise the current evidence base pertaining to autistic camouflaging. Following a systematic search of eight databases, 29 studies quantifying camouflaging in children and adults with autism diagnoses or high levels of autistic traits were reviewed. The multiple methods used to measure camouflaging broadly fell under two different approaches: internal-external discrepancy or self-report. These approaches appear to relate to two distinct but potentially connected elements of camouflaging: observable behavioural presentations and self-perceived camouflaging efforts. While significant variation was noted across individual study findings, much of the existing literature supported three preliminary findings about the nature of autistic camouflaging: (1) adults with more self-reported autistic traits report greater engagement in camouflaging; (2) sex and gender differences exist in camouflaging; and (3) higher self-reported camouflaging is associated with worse mental health outcomes. However, the research base was limited regarding participant characterisation and representativeness, which suggests that conclusions cannot be applied to the autistic community as a whole. We propose priorities for future research in refining the current understanding of camouflaging and improving measurement methods.
Topics: Adaptation, Psychological; Adult; Autistic Disorder; Child; Humans; Self Report; Sex Factors
PubMed: 34563942
DOI: 10.1016/j.cpr.2021.102080 -
Evidence-Based Practices for Children, Youth, and Young Adults with Autism: Third Generation Review.Journal of Autism and Developmental... Nov 2021This systematic review describes a set of practices that have evidence of positive effects with autistic children and youth. This is the third iteration of a review of...
This systematic review describes a set of practices that have evidence of positive effects with autistic children and youth. This is the third iteration of a review of the intervention literature (Odom et al. in J Autism Dev Disorders 40(4):425-436, 2010a; Prevent School Fail 54(4):275-282, 2010b; Wong et al. in https://autismpdc.fpg.unc.edu/sites/autismpdc.fpg.unc.edu/files/imce/documents/2014-EBP-Report.pdf ; J Autism Dev Disorders 45(7):1951-1966, 2015), extending coverage to articles published between 1990 and 2017. A search initially yielded 31,779 articles, and the subsequent screening and evaluation process found 567 studies to include. Combined with the previous review, 972 articles were synthesized, from which the authors found 28 focused intervention practices that met the criteria for evidence-based practice (EBP). Former EBPs were recategorized and some manualized interventions were distinguished as meeting EBP criteria. The authors discuss implications for current practices and future research.
Topics: Adolescent; Autism Spectrum Disorder; Autistic Disorder; Child; Evidence-Based Practice; Humans; Schools; Young Adult
PubMed: 33449225
DOI: 10.1007/s10803-020-04844-2