In The Politics of Autism, I discuss evaluation, diagnosis, and the uncertainty of prevalence estimates. I also I discuss various ideas about what causes the condition. Dozens of potential causes and correlates have been the subject of scientific and medical research.
The medical and scientific communities are looking at the same rising numbers, but they interpret them in different ways. Authors like Frith and Croce argue that a portion of newly diagnosed people may not have the condition at all, and are being mislabeled at the cost of correct treatment. They suggest that diagnostic drift is pulling people with ADHD, complex trauma, or personality disorders into the autism spectrum.
Other researchers focus on the expansion of diagnostic boundaries in the 1990s and on shifting administrative practices. Several of these papers converge on a similar conclusion. Kim, Russell, Matson, Talantseva, and Ranjan each attribute most of the rising trend to some combination of better case-finding, financial incentives, expanded criteria, and a demographic shift toward adults and females. Notably, the review by Lyall and colleagues, which is frequently cited by those exploring environmental risk factors, explicitly attributes much of the reported increase to changes in reporting practices. The drop in the proportion of cases involving intellectual disability points in the same direction, though Russell and colleagues caution that an actual increase in autism incidence cannot be entirely ruled out.
At the same time, several of the exposures most often proposed in public debate, including childhood vaccines, prenatal pain relievers, and antidepressants, have now been examined in large cohorts and sibling-matched designs without finding support for a causal link. That narrows the range of biological explanations still in play, leaving rising factors like advanced parental age, maternal obesity, and systemic inflammation as the credible candidates for a modest increase in underlying risk. As science continues to refine how we measure both the environment and the human brain, the balance between shifting medical labels and biological changes will continue to come into sharper focus.
References
The paper, “Individualized disability support schemes and their impact on autism diagnoses,” was authored by Maathumai Ranjan and Robert Breunig (2026) in the Journal of Health Economics.
The paper, “The increasing prevalence of autism spectrum disorders,” was authored by Johnny L. Matson and Alison M. Kozlowski (2011) in Research in Autism Spectrum Disorders.
The paper, “Prevalence of Autism Spectrum Disorder Among Children and Adolescents in the United States from 2021 to 2022,” was authored by Xiaofang Yan, Yanmei Li, Qishan Li, Qian Li, Guifeng Xu, Jinhua Lu, and Wenhan Yang (2024) in the Journal of Autism and Developmental Disorders.
The paper, “The Changing Epidemiology of Autism Spectrum Disorders,” was authored by Kristen Lyall, Lisa Croen, Julie Daniels, M. Daniele Fallin, Christine Ladd-Acosta, Brian K. Lee, Bo Y. Park, Nathaniel W. Snyder, Diana Schendel, Heather Volk, Gayle C. Windham, and Craig Newschaffer (2017) in the Annual Review of Public Health.
The paper, “Global prevalence of autism: A systematic review update,” was authored by Jinan Zeidan, Eric Fombonne, Julie Scorah, Alaa Ibrahim, Maureen S. Durkin, Shekhar Saxena, Afiqah Yusuf, Andy Shih, and Mayada Elsabbagh (2022) in Autism Research.
The paper, “Autism spectrum disorder: has it lost its meaning and is it leading to misdiagnosis?,” was authored by Uta Frith (2026) in Psychological Medicine.
The paper, “Time trends in the male to female ratio for autism incidence: population based, prospectively collected, birth cohort study,” was authored by Caroline Fyfe, Henric Winell, Joseph Dougherty, David H Gutmann, Alexander Kolevzon, Natasha Marrus, Kristina Tedroff, Tychele N Turner, Lauren A Weiss, Benjamin H K Yip, Weiyao Yin, and Sven Sandin (2026) in The BMJ.
The paper, “Time trends in autism diagnosis over 20 years: a UK population-based cohort study,” was authored by Ginny Russell, Sal Stapley, Tamsin Newlove-Delgado, Andrew Salmon, Rhianna White, Fiona Warren, Anita Pearson, and Tamsin Ford (2022) in the Journal of Child Psychology and Psychiatry.
The paper, “Cumulative Incidence and Prevalence of Autism Spectrum Disorder,” was authored by Young Shin Kim, Xiao Liu, Joshua Chang, Yun-Joo Koh, Jihyun Kim, Yuji Choi, Yoon Jae Cho, Eric Fombonne, and Bennett L. Leventhal (2026) in JAMA Pediatrics.
The paper, “The global prevalence of autism spectrum disorder: A three-level meta-analysis,” was authored by Oksana I. Talantseva, Raisa S. Romanova, Ekaterina M. Shurdova, Tatiana A. Dolgorukova, Polina S. Sologub, Olga S. Titova, Daria F. Kleeva, and Elena L. Grigorenko (2023) in Frontiers in Psychiatry.
The paper, “Diagnostic inflation in autism spectrum disorder: an epistemological and methodological reappraisal,” was authored by Luigi Croce and Irene Fusaro (2026) in Frontiers in Psychiatry.
The paper, “Environmental pollutants as risk factors for autism spectrum disorders: a systematic review and meta-analysis of cohort studies,” was authored by Tatiana Duque-Cartagena, Marcello Dala Bernardina Dalla, Eduardo Mundstock, Felipe Kalil Neto, Sergio Angelo Rojas Espinoza, Sara Kvitko de Moura, Gabriele Zanirati, Alexandre Vontobel Padoin, Juan Gabriel Piñeros Jimenez, Airton Tetelbom Stein, Wilson Cañon-Montañez, and Rita Mattiello (2024) in BMC Public Health.
The paper, “Prenatal environmental risk factors for autism spectrum disorder and their potential mechanisms,” was authored by Chloe Love, Luba Sominsky, Martin O’Hely, Michael Berk, Peter Vuillermin, and Samantha L. Dawson (2024) in BMC Medicine.
The paper, “The growing challenge of autism spectrum disorder: a comprehensive review of etiology, diagnosis, and therapy in children,” was authored by Chunyuan Wang and Hong Wang (2024) in All Life.
The paper, “Association Between First MMR Vaccination Before Age 2 Years and Childhood Autism in a U.S. EHR Cohort of 2.5 Million Children,” was authored by Todd L. Burstain, Dale Jacques, and Jennifer M. Burstain (2026) in The Pediatric Infectious Disease Journal.
The paper, “Neonatal Medical Male Circumcision and Child Autism Diagnosis,” was authored by Monica McGrath, Xiuhong Li, Lisa P. Jacobson, Bennett Leventhal, Judy L. Aschner, Brennan Baker, Karla Cardoso Garcia, Aisha S. Dickerson, Amy J. Elliott, Jody Ganiban, Amanda Goodrich, Daniel B. Horton, Melinda Jarnecke, Sarah Keim, Brian K. Lee, Courtney D. Lynch, Mark Klebanoff, Abdul-Manaf Mutaru, Ruby H. N. Nguyen, Rebecca J. Schmidt, Hyeong-Moo Shin, Lauren C. Shuffrey, Jonathan L. Slaughter, Annemarie Stroustrup, Zhaozhong Zhu, Aaron A. R. Tobian, and M. Kate Grabowski (2026) in JAMA Pediatrics.
The paper, “Prenatal exposure to maternal depression and antidepressants and neurodevelopmental outcomes: A population cohort study,” was authored by Saraid McIlvride, Neha Rao, Sarjit Singh, Scott M. Nelson, Jill P. Pell, and Michael Fleming (2026) in PLOS Medicine.
