When we take an antidepressant only part of it is absorbed by our bodies. We excrete the rest and some of the drug ends up, via water treatment plants, in the ocean. As a result of this it ends up being consumed by fish, none of which have a valid prescription for the drug.
Scientists ran a two-year experiment to look at the effects of one particular antidepressant — fluoxetine, often branded as Prozac — on guppy fish.
The results were stark: the fish on antidepressants seemed to lose their capability for individuality as a result of their exposure, with variations in behaviour between separate animals diminishing as the dose got stronger.
This is a problem because:
More active and risk-prone individuals are likely to secure more resources and enjoy greater reproductive success, in turn bolstering species' fitness, genetic diversity, and overall resilience, the researchers say.
If every animal starts acting the same way, though — living their similar, dosed-up lives adrift in a sea of antidepressants and who knows what else — well, the writing could be on the wall.
The fish are probably fairly chilled about things, thanks to being dosed-up on Prozac, but what staggers me is the subtle ways in which humanity affects nature. I never would have guessed this actually happened, let alone thought about running some experiments on unsuspecting guppy fish to see how it affects them.