ADHD News & Research

Hyperactivity in Fish Linked to Bisphenol Exposure

A new study finds embryonic exposure to BPA and BPS impacts brain development and hyperactivity later in life for zebrafish — and potentially for humans, too.

January 15, 2015

A new study, completed by the University of Calgary, has linked the chemicals used in making plastic to hyperactivity in zebrafish, which are often used to study embryonic brain development because they share 80 percent of the genes found in humans, and have similar developmental processes.

Thanks to recent consumer pressure, manufacturers have largely stopped using bispenol A (BPA) in household plastics — like Nalgene bottles — and epoxy resins. The chemical was replaced with bisphenol S (BPS), which was presumed safer. However, the study’s results suggest that both chemicals may be dangerous. BPA and BPS were found to alter brain development in ways that led to increased hyperactivity in the fish examined.

For this research, scientists exposed zebrafish embryos to BPA and BPS concentrations of the same level found in two rivers in southern Alberta –a very low concentration. Yet, this even limited exposure impacted the number of neurons formed in the fishes’ developing brains. BPA exposure increased the number of neurons by 180 percent and BPS exposure sparked a 240 percent jump in neuron development, compared with developing zebrafish brains not exposed to the chemicals. After continued behavioral studies of the fish, researchers concluded that increased neuron development resulted in greater hyperactivity, one of the hallmark symptoms of ADHD.

They called it “a smoking gun” that linked negative changes in brain development to BPA and BPS exposure. While they concede that more research is necessary to understand human brain development en utero, they suggest that pregnant women limit their exposure to products containing bisphenols.