Claude Monet’s art is beautiful, but he was painting the sulfur-polluted skies of industrial London
Fine particulate matter shows the strongest link, but noise and nitrogen dioxide also raise the odds
STUDY: Zhang J et al, Frontiers in Psychiatry 2026;
STUDY TYPE: Meta-analysis
FUNDING: Independent
Background
ADHD is strongly genetic, but environment plays a role: lead, processed foods, food coloring, pesticides, screen time, and air pollution are all implicated, as is child abuse and neglect.
The Study
- 29 observational cohort studies: 9 focused on noise (102,638 participants), 23 on air pollutants (1,779,758 participants), 3 on both. Most from Asia, Europe, and North America.
- Fine particulate matter showed the clearest associations (linked to 32-47% higher risk, depending on particle size).
- Nitrogen dioxide (NO2) linked to 11% higher risk.
- Noise exposure reached statistical significance but with a minimal 3% risk (odds ratio of 1.03)
Ozone, sulfur dioxide, and nitrogen oxides showed no association.
Effects were consistently stronger for childhood exposure than prenatal exposure.
Limitations
All studies were observational, so causation can’t be established. Heterogeneity across studies was high. Residual confounding from socioeconomic factors, parental psychiatric history, and indoor exposures was a concern throughout.
Practice Implications
- Though these studies are observational, controlled animal studies, and a few controlled human studies, tell us air pollution does affect cognition.
- Advocacy for clean air policies is one place psychiatrists can have an outsized impact beyond the clinic.
— Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
