Smithsonian Magazine, 16 April 2025

Salmon Are Being Exposed to Our Anti-Anxiety Medication, and It’s Making Them Take More Risks, Study Suggests

Atlantic salmon exposed to a common anti-anxiety drug migrate faster, according to new research. That’s not necessarily a good thing.

Humans take a lot of medication, and small doses of those drugs—including antibiotics, antidepressants, birth control and more—find their way in the environment through wastewater, even after it’s treated. Nearly 1,000 different pharmaceuticals have been detected in waterways all over the world, even in Antarctica. Now, a new study sheds light on how these drugs affect wildlife behavior.

“Pharmaceutical pollution, or chemical pollution in general, is really this invisible agent of global change,” says Jack Brand, the study’s lead author and an environmental researcher at the Swedish University of Agricultural Sciences, to Benji Jones at Vox. “It’s probably posing a greater risk than at least what the public acknowledges. This is a potentially significant threat to our aquatic wildlife.”