Pharmaceutical drugs people are flushing down their toilets and trace amounts found in urine are ending up in the world's waterways. In these bodies of water, wild fish are exposed to anti-anxiety drugs, which are altering their behavior, according to a new study published in the journal Science this week.

The study's authors, researchers in Sweden, wanted to find out how various levels of Oxazepam would affect wild European perch. The underwater test subjects were raised in the wild. The researchers exposed one group of fish to minimal levels of the drug and another group to high levels of Oxazepam for seven days.

The scientists noted the fish exposed to higher concentrations of the drug ate zooplanton, the food source, at a sped-up pace. These fish also exhibited riskier behavior or apparent boldness. The drugged fish also were less social and more active. These side effects could be detrimental to ecosystems, according to the researchers.

[via Inhabitant]