Anti-depressants in Water Making Fish Anxious and Anti-Social

Fish exposed to anti-depressants such as Prozac become aggressive and anti-social, according to a new study.

The study by researchers at University of Wisconsin-Milwaukee found that pharmaceutical waste containing anti-depressants dumped into freshwater sources has changed the behavior of fishes.  Anti-depressants are one of the most commonly prescribed medications in the U.S with over 200 million prescriptions being filled every year. These drugs usually end up in streams where they alter the development of fish brains, according to a report by Environmental Health News.

Recently, Researchers from Umeå University found that fish started behaving differently when they were exposed to Oxazepam- a mood altering drug. Other studies have shown that birth control pills are wrecking the sex-life of fish by making the male fish less masculine and creating a condition called, intersex.

Researchers, in the present study, looked at the behavior of male fathead minnows when exposed to fluoxetine, also known as Prozac. They found that male minnows that were exposed to the drug avoided female minnows and spent most of the time alone. They also took more time to hunt for food. Researchers said that they used a very low dosage for the experiment, about one part per billion, which is on par with the concentration of the anti-depressant in freshwater sources.

The fishes were exposed to the drug while they were still growing and researchers found that the drug altered the behavior at the genetic level. Also, there were abnormalities in the development of nerve fibers in the brains of the minnows.

"At high doses we expect brain changes. But we saw the gene expression changes and then behavioral changes at doses that we consider environmentally relevant," Rebecca Klaper, a professor of freshwater sciences from UW-Milwaukee who worked on the study told Environmental Health News.

Pharmaceutical waste in drinking water has been a cause for concern for quite some time. However, a report  from the World Health Organization has found that the concentrations of pharmaceuticals in drinking water are too low to cause any damage to human health.

"Fish do not metabolize drugs like we do. Even if environmental doses aren't thought to be much for a human, fish could still have significant accumulation, and, it appears, changes in their brain's gene expression," Klaper added.