Relationship between PFAS and attention-deficit/hyperactivity disorder or autism spectrum disorder: Epidemiological and experimental evidence.

This review looks at chemicals called PFAS that are found everywhere in our environment - in water, food, and even in our bodies. Researchers found that these chemicals might be linked to ADHD and autism. PFAS can get into the brain and may cause problems with brain development, especially in babies and young children whose brains are still developing. The chemicals seem to cause inflammation and disrupt normal brain function, but more research is needed to prove they actually cause ADHD or autism.

This narrative review examines the relationship between per- and polyfluoroalkyl substances (PFAS) exposure and neurodevelopmental conditions, specifically ADHD and autism spectrum disorder. PFAS are widespread environmental contaminants found in drinking water, food, and human biological samples. The review synthesizes epidemiological evidence suggesting potential links between PFAS exposure and ADHD/ASD development, along with experimental data showing PFAS can penetrate the blood-brain barrier and disrupt neurotransmitter regulation. The developing brains of fetuses and infants appear particularly vulnerable due to incomplete barrier and immune system development.

The authors highlight mechanistic pathways including oxidative stress, neuroinflammation, and gut microbiota alterations that may contribute to these associations, while noting the need for stronger causal evidence through molecular epidemiological approaches.

While evidence suggests potential links between PFAS exposure and neurodevelopmental conditions, causal relationships remain unclear. Findings support the importance of minimizing environmental chemical exposures during pregnancy and early childhood. Further research using molecular epidemiological approaches is needed before definitive clinical recommendations can be made regarding PFAS exposure and neurodevelopmental risk.

This is a narrative review without systematic methodology. The authors acknowledge challenges in establishing causal links and note the need for stronger molecular epidemiological approaches and realistic exposure models in research to better understand causation.

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants found in various consumer products, such as drinking water, infant formula, and food, as well as in human biospecimens, including blood, urine, breastmilk, and cerebrospinal fluid. Previous evidence indicates that PFAS exposure poses significant neurotoxic risks, owing to their ability to penetrate the blood-brain barrier and bioaccumulate in neural tissue. The developing brains of fetuses and infants are particularly susceptible to the harmful effects of environmental pollutants because of their incomplete barrier and immune system development. This narrative review synthesizes current epidemiological and experimental evidence on the neurodevelopmental effects of PFAS exposure, with a primary focus on attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

The available data, from both cross-sectional and prospective cohort surveys, indicate a potential link between PFAS exposure and the development of ADHD or ASD. Additionally, experimental studies demonstrate that PFAS exposure disrupts neurotransmitter regulation, induces oxidative stress and chronic neuroinflammation, and alters gut microbiota, all of which reflect key pathological features observed in both clinical and preclinical models of ADHD and ASD. The present narrative review also discusses current challenges and research directions aimed at elucidating the causal links between PFAS insults and the onset of ADHD or ASD. Notably, this review highlights the need for molecular epidemiological approaches and realistic exposure models in animal research to deepen our understanding of causal associations.