Effectiveness of a school-based Life Gatekeeper Training Program on suicide prevention in China: protocol for a randomized controlled trial.

BACKGROUND: With suicide as a leading cause of death, the issue of children and adolescent suicide risks is in the spotlight today. To empower teachers in primary and secondary schools to serve as gatekeepers and to ensure the safety of children and adolescents, the systematically tailored and localized Life Gatekeeper suicide prevention program was designed for Chinese schools. OBJECTIVE: With the ultimate goal of preventing child and adolescent suicide, we aim to outline a research protocol for examining outcomes of the recently created standardized school-based Life Gatekeeper program in reducing teachers' stigma, increasing their knowledge, willingness to intervene, and perceived competence. METHODS: Participants will be recruited from eligible primary and secondary schools. Cluster sampling will be used to randomly assign each school to either the intervention group or the control group. The primary outcomes are stigma against suicide, suicide literacy, perceived competence, and willingness to intervene with suicidal individuals, which will be measured using the Stigma of Suicide Scale, the Literacy of Suicide Scale, and the Willingness to Intervene Against Suicide Questionnaire, respectively. Measurements will be taken at four time points, including pre-intervention, immediately after the intervention, 6-month follow-up, and 1-year follow-up. CONCLUSIONS: The current study features innovative implementation in the real world, by using a randomized controlled trial design to examine the effectiveness of a school-based gatekeeper program among primary and secondary school teachers, following a sequence of defined and refined steps. The research will also investigate the viability of a school-based gatekeeper program for primary and secondary school teachers that could be quickly and inexpensively implemented in a large number of schools.

The influence of economic policies on social environments and mental health.

Despite increased advocacy and investments in mental health systems globally, there has been limited progress in reducing mental disorder prevalence. In this paper, we argue that meaningful advancements in population mental health necessitate addressing the fundamental sources of shared distress. Using a systems perspective, economic structures and policies are identified as the potential cause of causes of mental ill-health. Neoliberal ideologies, prioritizing economic optimization and continuous growth, contribute to the promotion of individualism, job insecurity, increasing demands on workers, parental stress, social disconnection and a broad range of manifestations well-recognized to erode mental health. We emphasize the need for mental health researchers and advocates to increasingly engage with the economic policy discourse to draw attention to mental health and well-being implications. We call for a shift towards a well-being economy to better align commercial interests with collective well-being and social prosperity. The involvement of individuals with lived mental ill-health experiences, practitioners and researchers is needed to mobilize communities for change and influence economic policies to safeguard well-being. Additionally, we call for the establishment of national mental wealth observatories to inform coordinated health, social and economic policies and realize the transition to a more sustainable well-being economy that offers promise for progress on population mental health outcomes.

Malgré une meilleure sensibilisation et des investissements accrus dans les systèmes de santé mentale à travers le monde, les progrès en matière de réduction du degré de prévalence des troubles mentaux demeurent très limités. Dans le présent document, nous estimons que, pour réaliser des avancées au niveau de la santé mentale des populations, il est impératif de s'attaquer aux sources de cette détresse collective. En adoptant une perspective systémique, force est de constater que les politiques et structures économiques constituent les causes potentielles d'une mauvaise santé mentale. Les idéologies néolibérales, qui privilégient l'optimisation économique et la croissance ininterrompue, contribuent à promouvoir l'individualisme, l'insécurité professionnelle, la pression pesant sur les travailleurs, le stress parental, l'isolement social et un large éventail de facteurs associés à une dégradation de la santé mentale. Nous insistons sur la nécessité de faire appel à des chercheurs et défenseurs actifs dans ce domaine, afin de jouer un rôle dans la politique économique en attirant l'attention sur les implications pour le bien-être et la santé mentale. Nous plaidons pour une transition vers une économie du bien-être visant à rapprocher les intérêts commerciaux de la prospérité sociale et collective. L'intervention de personnes ayant été confrontées à des troubles mentaux, de praticiens et de chercheurs est nécessaire pour mobiliser les communautés en faveur d'un changement et influencer les politiques économiques pour préserver le bien-être. Par ailleurs, nous militons pour la création d'observatoires nationaux de la santé mentale qui serviront à orienter des politiques économiques, sociales et sanitaires coordonnées, mais aussi à favoriser l'évolution vers une économie du bien-être plus durable, laissant entrevoir une amélioration de la santé mentale au sein de la population.

A pesar del aumento de la promoción y las inversiones en sistemas de salud mental en todo el mundo, los avances en la reducción de la prevalencia de los trastornos mentales han sido limitados. En este documento, sostenemos que para lograr avances significativos en la salud mental de la población es necesario abordar las fuentes fundamentales de la angustia compartida. Mediante una perspectiva sistémica, las estructuras y políticas económicas se identifican como la posible causa de los problemas de salud mental. Las ideologías neoliberales, que priorizan la optimización económica y el crecimiento continuo, contribuyen al fomento del individualismo, la inseguridad laboral, el aumento de las exigencias a los trabajadores, el estrés parental, la desconexión social y una gran variedad de manifestaciones bien reconocidas que perjudican la salud mental. Insistimos en la necesidad de que los investigadores y los defensores de la salud mental se impliquen cada vez más en el discurso de la política económica para atraer la atención sobre las implicaciones para la salud mental y el bienestar. Pedimos un cambio hacia una economía del bienestar para alinear mejor los intereses comerciales con el bienestar colectivo y la prosperidad social. Para movilizar a las comunidades en favor del cambio e influir en las políticas económicas con el fin de salvaguardar el bienestar, es necesaria la participación de personas que han padecido enfermedades mentales, profesionales e investigadores. Además, pedimos la creación de observatorios nacionales de bienestar mental que sirvan de base a las políticas sanitarias, sociales y económicas coordinadas y permitan la transición a una economía del bienestar más sostenible, que ofrezca perspectivas de progreso en los resultados de salud mental de la población.

Social determinants of mental health in major depressive disorder: Umbrella review of 26 meta-analyses and systematic reviews.

There is a growing recognition of the impact of social determinants of mental health (SDoMHs) on people with, or at risk of, developing serious mental illnesses. Yet it is not known how associations of individual SDoMHs with risk for major depressive disorder (MDD) vary and roughly compare with one another. Following PRISMA guidelines, this umbrella review included 26 meta-analyses and systematic reviews that reported odds ratios, effect sizes, and/or pooled prevalence rates of MDD in samples with versus without specified SDoMHs. Childhood emotional, physical, or sexual abuse and neglect; intimate partner violence in females; and food insecurity were significantly associated with increased risk of MDD, with medium effect sizes. Natural disasters, terrorist acts, and military combat during deployment had small-size adverse effects, and homelessness, incarceration, and migration were associated with significantly elevated prevalence of MDD. Conversely, higher levels of parental care were significantly associated with reduced risk of MDD with medium effect sizes. Evidence supports the use of certain interventions at the individual and community level that can reduce the impact of these factors and promote health, although much more research is warranted in this area along with meaningful healthcare and societal policies to accomplish this goal.

Single-wavelength bidirectional 4-core MCF self-homodyne coherent link.

In this paper, we propose and demonstrate a single-wavelength bidirectional self-homodyne coherent (SHC) link over a 125 µm cladding diameter based multicore fiber (MCF). The 4-core MCF based link efficiently uses two cores for each direction of propagation. In either direction, one of the cores carries a dual-polarized 40 Gbaud 16-QAM signal, and the second core carries a 40 Gbaud 16-QAM signal in one of the polarizations with the carrier multiplexed in its orthogonal polarization. Thus, a 480 Gbps data transmission rate is achieved in either direction of propagation over the 12.8 km long 4-core MCF. The SHC link operates at the same wavelength for each of the directions and eliminates the need for reconfigurable transceivers. A low-cost DFB laser (linewidth = 1 MHz) is used to demonstrate the bidirectional link, and the bit error rates (BERs) of the received signals are <5.5×10-4. With higher baud rates, this approach can meet the capacity requirements of future short-reach data center interconnects (DCIs).

A theory of change for community-initiated mental health care in the United States.

Mental health service delivery needs radical reimagination in the United States where unmet needs for care remain large and most metrics on the burden of mental health problems have worsened, despite significant numbers of mental health professionals, spending on service provision and research. The COVID-19 pandemic has exacerbated the need for mental health care. One path to a radical reimagination is "Community Initiated Care (CIC)" which equips and empowers communities to address by providing brief psychosocial interventions by people in community settings. We co-developed a theory of change (ToC) for CIC with 24 stakeholders including representatives from community-based, advocacy, philanthropic and faith-based organizations to understand how CIC could be developed and adapted for specific contexts. We present a ToC which describes ways in which the CIC initiative can promote and strengthen mental health in communities in the United States with respect to community organization and leadership; community care and inclusion and normalizing mental health. We propose 10 strategies as part of CIC and propose a way forward for implementation and evaluation. This CIC model is a local, tailored approach which can expand the role of community members to strengthen our response to mental health needs in the United States.

Transforming mental health systems globally: principles and policy recommendations.

A burgeoning mental health crisis is emerging globally, regardless of each country's human resources or spending. We argue that effectively responding to this crisis is impeded by the dominant framing of mental ill health through the prism of diagnostic categories, leading to an excessive reliance on interventions that are delivered by specialists; a scarcity of widespread promotive, preventive, and recovery-oriented strategies; and failure to leverage diverse resources within communities. Drawing upon a series of syntheses, we identify five principles to transform current practices; namely, address harmful social environments across the life course, particularly in the early years; ensure that care is not contingent on a categorical diagnosis but aligned with the staging model of mental illness; empower diverse front-line providers to deliver psychosocial interventions; embrace a rights-based approach that seeks to provide alternatives to violence and coercion in care; and centre people with lived experience in all aspects of care. We recommend four policy actions which can transform these principles into reality: a whole of society approach to prevention and care; a redesign of the architecture of care delivery to provide a seamless continuum of care, tailored to the severity of the mental health condition; investing more in what works to enhance the impact and value of the investments; and ensuring accountability through monitoring and acting upon a set of mental health indicators. All these actions are achievable, relying-for the most part-on resources already available to every community and country. What they do require is the acceptance that business as usual will fail and the solutions to transforming mental health-care systems are already present within existing resources.

Mental disorders and COVID-19 deaths: Clinical, public health, and human rights implications.

Shekhar Saxena and Cindy Chwa discuss the neglect of care for people living with mental disorders during the pandemic, and highlight relevant implications for policy-makers.

Review of Major Social Determinants of Health in Schizophrenia-Spectrum Psychotic Disorders: I. Clinical Outcomes.

BACKGROUND: Social determinants of health (SDoHs) are receiving growing attention and are particularly relevant to persons with schizophrenia-spectrum psychotic disorders (SSPDs), considering their heightened risk of comorbidities, cognitive and functional decline, and early mortality. Yet, we did not find any comprehensive review of multiple SDoHs in SSPD. STUDY DESIGN: We conducted a scoping review of meta-analyses and systematic reviews of nine major SDoHs in SSPD. STUDY RESULTS: Childhood abuse, parental psychopathology, parental communication problems, bullying, and urban settings with lower socioeconomic status were major risk factors for the greater incidence of SSPD and/or worse health. Social network size was inversely associated with overall psychopathology and negative symptoms. Experiences of racial/ethnic discrimination correlated with the prevalence of psychotic symptoms and experiences. Compared to native populations, the risk of psychosis was higher in immigrants, refugees, and asylees. Social fragmentation was associated with an increased prevalence of schizophrenia. Homeless populations had a 30-fold higher prevalence of schizophrenia than the general population. Seriously mentally ill people were 2.7 times more likely to report food insecurity than controls. The prevalence of non-affective psychosis in prisoners was 2.0%-6.5%, compared to 0.3% in the general population. Certain potentially positive factors like family and community resilience remain poorly studied. CONCLUSIONS: SDoHs are associated with higher rates of and worse outcomes in SSPD. Well-designed longitudinal studies are needed to understand SDoHs' contribution to health in persons with SSPD, to develop interventions, and to implement changes in clinical care and public health policies that would reduce adverse health impacts of SDoHs. Positive SDoHs deserve greater attention.

Scaling up community-delivered mental health support and care: A landscape analysis.

Introduction: The mental health crisis has caused widespread suffering and has been further exacerbated by the COVID-19 pandemic. Marginalized groups are especially affected, with many concerns rooted in social determinants of mental health. To stem this tide of suffering, consideration of approaches outside the traditional biomedical model will be necessary. Drawing from task-sharing models of mental health care that have been pioneered in low-resource settings, community-initiated care (CIC) represents a potentially promising collection of approaches. This landscape analysis seeks to identify examples of CIC that have been implemented outside of the research context, with the aim of identifying barriers and facilitators of scale up. Methods: A narrative review approach was used for this landscape analysis in which the PubMed database was searched and further supplemented with Google Scholar. Promising programs were then discussed over multiple rounds of meetings with the research team, consisting of collaborators with varied experiences in mental health. Using the selection criteria and feedback derived from group meetings, a final list of programs was identified and summarized according to common characteristics and features. Results: The initial PubMed search yielded 16 results, supplemented by review of the first 100 entries in Google Scholar. Through 5 follow-up meetings among team members, consensus was reached on a final list of 9 programs, which were grouped into three categories based on similar themes and topics: (1) approaches for the delivery of psychosocial interventions; (2) public health and integrative approaches to mental health; and (3) approaches for addressing youth mental health. Key facilitators to scale up included the importance of sustainable financing and human resources, addressing social determinants and stigma, engaging diverse stakeholders, leveraging existing health infrastructure, using sustainable training models, ensuring cultural relevance and appropriateness, and leveraging digital technologies. Discussion: This landscape analysis, though not an exhaustive summary of the literature, describes promising examples of efforts to scale up CIC outside of the research context. Going forward, it will be necessary to mobilize stakeholders at the community, health system, and government levels to effectively promote CIC.

Quantifying the global burden of mental disorders and their economic value.

Background: Epidemiological and economic estimates suggest that the global burden of mental disorders is considerable, both in its impacts on human health and losses to societal welfare. The availability of additional data and the emergence of new approaches present an opportunity to examine these estimates, which form a critical part in making the investment case for global mental health. Methods: This study reviews, develops, and incorporates new estimates and methods in quantifying the global burden of mental illness. Using a composite estimation approach that accounts for premature mortality due to mental disorders and additional sources of morbidity and applying a value of a statistical life approach to economic valuation, we determine global and regional estimates of the economic cost that can be associated with mental disorders, building on data from the 2019 Global Burden of Disease study. Findings: We estimate that 418 million disability-adjusted life years (DALYs) could be attributable to mental disorders in 2019 (16% of global DALYs)-a more than three-fold increase compared to conventional estimates. The economic value associated with this burden is estimated at about USD 5 trillion. At a regional level, the losses could account for between 4% of gross domestic product in Eastern sub-Saharan Africa and 8% in High-income North America. Interpretation: The burden of mental illness in terms of both health and economic losses may be much higher than previously assessed. Funding: None.

Operational challenges in the pre-intervention phase of a mental health trial in rural India: reflections from SMART Mental Health.

BACKGROUND: Availability of mental health services in low- and middle-income countries is largely concentrated in tertiary care with limited resources and scarcity of trained professionals at the primary care level. SMART Mental Health is a strategy that combines a community anti-stigma campaign with a primary health care workforce strengthening initiative, using electronic decision support with the goal of better identifying and supporting people with common mental disorders in India. METHODS: We describe the challenges faced and lessons learnt during the pre-intervention phase of SMART Mental Health cluster Randomised Controlled Trial. Pre-intervention phase includes preliminary activities for setting-up the trial and research activities prior to delivery of the intervention. Field notes from project site visit, project team meetings and detailed follow-up discussions with members of the project team were used to document operational challenges and strategies adopted to overcome them. The socio-ecological model was used as the analytical framework to organise the findings. RESULTS: Key challenges included delays in government approvals, addressing community health worker needs, and building trust in the community. These were addressed through continuous communication, leveraging support of relevant stakeholders, and addressing concerns of community health workers and community. Issues related to use of digital platform for data collection were addressed by a dedicated technical support team. The COVID-19 pandemic and political unrest led to significant and unexpected challenges requiring important adaptations to successfully implement the project. CONCLUSION: Setting up of this trial has posed challenges at a combination of community, health system and broader socio-political levels. Successful mitigating strategies to overcome these challenges must be innovative, timely and flexibly delivered according to local context. Systematic ongoing documentation of field-level challenges and subsequent adaptations can help optimise implementation processes and support high quality trials. TRIAL REGISTRATION: The trial is registered with Clinical Trials Registry India (CTRI/2018/08/015355). Registered on 16th August 2018. http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=23254&EncHid=&userName=CTRI/2018/08/015355.

The global return on investment from preventing and treating adolescent mental disorders and suicide: a modelling study.

INTRODUCTION: Despite the high burden of mental disorders among adolescents and the potentially lifelong consequences of these conditions, access to mental health services remains insufficient for adolescents in low-income and middle-income countries. We conducted an economic modelling study to quantify the potential costs and benefits of mental health interventions to prevent or treat anxiety, depression, bipolar disorder, and suicide among adolescents. METHODS: We developed a Markov model that followed cohorts of adolescents (ages 10-19) from 36 countries to assess the impact of addressing anxiety, depression, bipolar disorder, and suicide during adolescence on health and non-health outcomes through their lives. We estimated the costs of interventions using an ingredients-based approach and modelled impacts on education and employment and the resulting economic, morbidity, and mortality benefits. RESULTS: Implementing the selected interventions offers a return on investment of 23.6 and a cost of $102.9 per disability adjusted life year (DALY) averted over 80 years. The high return on investment and low cost per DALY averted is observed across regions and country income levels, with the highest return on investment arising from treating mild depression with group-based cognitive behavioural therapy, prevention of suicide attempts among high-risk adolescents, and universal prevention of combined anxiety and depression in low-income and lower-middle income countries. CONCLUSIONS: The high return on investment and low cost per DALY averted suggests the importance and value of addressing mental disorders among adolescents worldwide. Intervening to prevent and treat these mental disorders even only during adolescence can have lifelong health and economic benefits.

Protocol for process evaluation of SMART Mental Health cluster randomised control trial: an intervention for management of common mental disorders in India.

INTRODUCTION: In India about 95% of individuals who need treatment for common mental disorders like depression, stress and anxiety and substance use are unable to access care. Stigma associated with help seeking and lack of trained mental health professionals are important barriers in accessing mental healthcare. Systematic Medical Appraisal, Referral and Treatment (SMART) Mental Health integrates a community-level stigma reduction campaign and task sharing with the help of a mobile-enabled electronic decision support system (EDSS)-to reduce psychiatric morbidity due to stress, depression and self-harm in high-risk individuals. This paper presents and discusses the protocol for process evaluation of SMART Mental Health. METHODS AND ANALYSIS: The process evaluation will use mixed quantitative and qualitative methods to evaluate implementation fidelity and identify facilitators of and barriers to implementation of the intervention. Case studies of six intervention and two control clusters will be used. Quantitative data sources will include usage analytics extracted from the mHealth platform for the trial. Qualitative data sources will include focus group discussions and interviews with recruited participants, primary health centre doctors, community health workers (Accredited Social Health Activits) who participated in the project and local community leaders. The design and analysis will be guided by Medical Research Council framework for process evaluations, the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework, and the normalisation process theory. ETHICS AND DISSEMINATION: The study has been approved by the ethics committee of the George Institute for Global Health, India and the Institutional Ethics Committee, All India Institute of Medical Sciences (AIIMS), New Delhi. Findings of the study will be disseminated through peer-reviewed publications, stakeholder meetings, digital and social media platforms. TRIAL REGISTRATION NUMBER: CTRI/2018/08/015355.

Policy stringency and mental health during the COVID-19 pandemic: a longitudinal analysis of data from 15 countries.

BACKGROUND: To date, public health policies implemented during the COVID-19 pandemic have been evaluated on the basis of their ability to reduce transmission and minimise economic harm. We aimed to assess the association between COVID-19 policy restrictions and mental health during the COVID-19 pandemic. METHODS: In this longitudinal analysis, we combined daily policy stringency data from the Oxford COVID-19 Government Response Tracker with psychological distress scores and life evaluations captured in the Imperial College London-YouGov COVID-19 Behaviour Tracker Global Survey in fortnightly cross-sections from samples of 15 countries between April 27, 2020, and June 28, 2021. The mental health questions provided a sample size of 432 642 valid responses, with an average of 14 918 responses every 2 weeks. To investigate how policy stringency was associated with mental health, we considered two potential mediators: observed physical distancing and perceptions of the government's handling of the pandemic. Countries were grouped on the basis of their response to the COVID-19 pandemic as those pursuing an elimination strategy (countries that aimed to eliminate community transmission of SARS-CoV-2 within their borders) or those pursuing a mitigation strategy (countries that aimed to control SARS-CoV-2 transmission). Using a combined dataset of country-level and individual-level data, we estimated linear regression models with country-fixed effects (ie, dummy variables representing the countries in our sample) and with individual and contextual covariates. Additionally, we analysed data from a sample of Nordic countries, to compare Sweden (that pursued a mitigation strategy) to other Nordic countries (that adopted a near-elimination strategy). FINDINGS: Controlling for individual and contextual variables, higher policy stringency was associated with higher mean psychological distress scores and lower life evaluations (standardised coefficients ß=0·014 [95% CI 0·005 to 0·023] for psychological distress; ß=-0·010 [-0·015 to -0·004] for life evaluation). Pandemic intensity (number of deaths per 100 000 inhabitants) was also associated with higher mean psychological distress scores and lower life evaluations (standardised coefficients ß=0·016 [0·008 to 0·025] for psychological distress; ß=-0·010 [-0·017 to -0·004] for life evaluation). The negative association between policy stringency and mental health was mediated by observed physical distancing and perceptions of the government's handling of the pandemic. We observed that countries pursuing an elimination strategy used different policy timings and intensities compared with countries pursuing a mitigation strategy. The containment policies of countries pursuing elimination strategies were on average less stringent, and fewer deaths were observed. INTERPRETATION: Changes in mental health measures during the first 15 months of the COVID-19 pandemic were small. More stringent COVID-19 policies were associated with poorer mental health. Elimination strategies minimised transmission and deaths, while restricting mental health effects. FUNDING: None.

Human-centered design exploration with Kenyan health workers on proposed digital mental health screening and intervention training development: Thematic analysis of user preferences and needs.

Background: Health providers' perceived sense of knowledge, competency, and self-efficacy to support the needs of their patients contributes to optimal patient health outcomes. With regards to mental health service delivery in Kenya, this area needs further exploration. Guided by the e-health technology acceptance mode, the needs and preferences of health care providers around mental health training for clinical management and their ability to intervene in peripartum adolescent mental health care are explored. We probed how well-equipped service providers are, their engagement with technology to learn and offer services. The health care provider's technology use preferences were also explored. Method: Guided by a human-centered design-focused qualitative inquiry we interviewed 20 specialists around their needs, perspectives, and preferences for digitized mental health screening and intervention. Mean age was 44.2 years, (range of 32-58 years), 25% (5) males and 75% (15) females. After a written consenting process, the online interviews (30-45 min) were conducted in April 2021, once personal information was de-identified interviews were transcribed and coded. Thematic analysis was used and we combined rapid appraisal of Google Jamboard online storyboards to do individual human-centered design personas alongside. Results: Our participants were well-exposed to digital technologies. Prohibitive costs of data bundles, lack of funds for consistent online engagement, high workload, and instability of access to appropriate gadgets were found to be barriers to e-health training. Emerging opportunities were well-identified adolescent mental health service and intervention needs, willingness to take online courses offered on learning platforms, and wish for these to be disseminated through diverse social media. Other recommendations were the need to have a user-friendly interface such as data-light engaging and practical materials including animations, short, group-based learning. Conclusion: Understanding contextual factors that influence perceived usefulness and ease of use of the remote/digital components would be critical for e-training development and its uptake.

Global prevalence of autism: A systematic review update.

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.