Study Finds Anti-Anxiety Drug Traces In Waterways Make Fish Bolder And More Voracious Feeders

It looks like our psychiatric drugs may have an effect on more than just people. A new study shows that the trace amounts of a common anti-anxiety drug that end up in rivers could be altering the behaviors of unsuspecting fish. 

In a study published in the journal Science, researchers from Sweden tested out whether Oxazepam, a drug taken to treat anxiety, had any effect on wild European perch. Turns out that fish exposed to the drug end up eating more and being less social. 

"Here we show that a benzodiazepine anxiolytic drug (oxazepam) alters behavior and feeding rate of wild European perch (Perca fluviatilis) at concentrations encountered in effluent-influenced surface waters," reads the study abstract. 

"Individuals exposed to water with dilute drug concentrations (1.8 micrograms liter-1) exhibited increased activity, reduced sociality, and higher feeding rate. As such, our results show that anxiolytic drugs in surface waters alter animal behaviors that are known to have ecological and evolutionary consequences."

The repercussions of such a study, the scientists hope, will be to raise awareness about the environmental side effects of human products such as medications and even cosmetics. Oxazepam, and a number of other drugs have the potential to enter waterways through wastewater, as the drugs pass through the bodies of those take it. 

Still, there are far too many variables at play for the study to be concluded a definitive "we are messing with the minds of fish" statement. Concentrations of human byproducts vary depending on the part of the waterway, and the levels tested were higher than those that would be found in Swedish rivers and streams. The United States Environmental Protection Agency stated that most of our known pharmaceuticals aren't noticeable threats to our environment, and even went as far as to say that "the relevance of their study to the real world is unclear."

Still, the researchers, and others are echoing the same thought: we need to be more conscious of how human byproducts, even our organic waste, can alter the world around us. 

"We're smart enough and we should be able to design chemicals that fulfill these same sorts of functions but with less stress on the environment," Donald Tillitt, a toxicologist with the United States Geological Survey, said.