Are Our Medications Causing Mood Changes in Fish?


Are Our Medications Causing Mood Changes in Fish?

Our meds may be causing mood changes in fish, making them hyper, aggressive, and antisocial.

New research is again showing just how connected we are to our environment, and the animals with which we share it. Although researchers have known for quite some time that the pharmaceuticals we take end up in our waterways (after we excrete or flush them and they’ve been treated at water plants) they’re still uncovering the implications of these drugs being in the environment.

A new Swedish study recently published in the journal Science found that fish that swim in waters tainted with these drugs (in this case, the researchers studied European perch) can develop a host of mood changes. An anti-anxiety drug, for instance, can cause the fish to become hyper, aggressive, and antisocial.

The marine environment is such a delicate ecosystem that even the smallest change can upset the natural balance. In this case, hyper, aggressive, and antisocial fish are thought to make themselves more vulnerable to predators by venturing out on their own. Only time can tell what the true effects will be, and how much of an impact they will have on the ecosystem.

And it’s not just fish who are dealing with the consequences of drugs in the waterways—previous research has found pharmaceuticals in the drinking water of Americans.

Want to read more?

  • Learn about pharmaceutical contamination in our Great Lakes.
  • Canada’s sewage treatment receives failing grades.
  • Is bottled water better? Not so fast. 
  • Pharmaceuticals aren’t the only things in our waterways harming marine life. Learn about marine plastic pollution, and what you can do to stop it.


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