Study Examines Links Between Infant Antibiotic Use and Risks of Autism and ADHD

September 27, 2026 2 Min Read

Early Antibiotic Exposure and Neurodevelopmental Outcomes

A recent nationwide study from Taiwan investigated how exposure to different antibiotics during infancy might relate to the risks of developing autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). The research analyzed health data from over 1.6 million term newborns born between 2004 and 2015, tracking their health outcomes through 2022.

Key Findings on Antibiotic Types and Administration Routes

The study found that the associations between antibiotic use in early life and later neurodevelopmental disorders varied depending on the specific antibiotic agent, the timing of exposure, and whether the medication was given orally or by injection.

Notably, oral antibiotic exposure was linked to a lower risk of ASD but a higher risk of ADHD. In contrast, parenteral (injectable) antibiotic exposure was associated with increased risks for both ASD and ADHD.

Specific Antibiotics and Their Associations

Lower ASD risk: Exposure to amoxicillin and erythromycin during the first year of life was associated with reduced ASD risk.
Higher ASD risk: Exposure to ampicillin between 4 and 12 months of age was linked to an increased risk of ASD.
ADHD risk increased with: amoxicillin/clavulanic acid, cefixime, ampicillin, and ampicillin/sulbactam.
ADHD risk decreased with: erythromycin, cephalexin, and sulfamethoxazole-trimethoprim.

Context and Implications for Families

ASD and ADHD are complex neurodevelopmental conditions influenced by multiple genetic and environmental factors. Antibiotics are commonly prescribed during infancy for various infections, but their impact on the developing brain and gut microbiome is an area of ongoing research.

This study’s findings suggest that not all antibiotics carry the same potential risks or benefits regarding neurodevelopmental outcomes. The route of administration and timing of antibiotic exposure may also play important roles.

For parents and caregivers, these results highlight the importance of judicious antibiotic use during infancy, balancing the need to treat infections effectively with consideration of potential long-term effects.

Study Limitations and Cautions

While the research benefits from a large, population-based dataset, it is observational and cannot establish cause and effect. The associations reported do not prove that antibiotics cause or prevent ASD or ADHD. Other factors, such as the underlying infections requiring antibiotics or genetic predispositions, might influence the observed relationships.

Further studies are needed to explore the biological mechanisms behind these associations and to confirm these findings in other populations.

For more detailed information, see the original study published in Pharmaceutics: Associations Between Early-Life Exposure to Different Antibiotic Agents and the Risks of Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder: A Nationwide Population-Based Study.