{"id":10407,"date":"2025-04-11T09:25:18","date_gmt":"2025-04-11T09:25:18","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/10407\/"},"modified":"2025-04-11T09:25:18","modified_gmt":"2025-04-11T09:25:18","slug":"a-drug-that-treats-seizures-and-anxiety-is-leaking-into-the-environment-and-affecting-fish","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/10407\/","title":{"rendered":"A drug that treats seizures and anxiety is leaking into the environment and affecting fish."},"content":{"rendered":"

For those of us with anxiety (hello!), the class of prescription drugs known as benzodiazepines, or benzos, can be a boon in times of crisis. Though they are addictive<\/a>, they\u2019re pretty good at chilling us out. <\/p>\n

But it turns out that by drugging ourselves with these pills, we are inadvertently drugging wild animals as well. Especially the ones that live in water. <\/p>\n

Our bodies don\u2019t absorb 100 percent of the drugs we ingest, so traces of them end up in the toilet. And because sewage treatment plants usually can\u2019t filter them all out<\/a>, those compounds ultimately end up where treated sewage is released \u2014 in rivers, lakes, and coastal habitats. <\/p>\n

This means that fish and other aquatic critters that live in these environments are, for better or worse, exposed to our meds. Basically, fish are on drugs \u2014 our drugs.<\/p>\n

What, exactly, does that mean for wildlife? That\u2019s what a relatively new field of research is trying to figure out. And a study<\/a> just published in the journal Science offers some compelling clues. <\/p>\n

The authors gave young Atlantic salmon in Sweden a dose of clobazam \u2014 a benzo used to treat seizures and anxiety that\u2019s often found in wastewater \u2014 equal to what some fish might naturally be exposed to in streams. Then they monitored what the drug did to the fish as they migrated, as young salmon do, from a river out to the Baltic Sea. <\/p>\n

\"A<\/a><\/p>\n

Dal\u00e4lven, the river in Sweden where the study took place. Michael Bertram<\/p>\n

\"A<\/a><\/p>\n

Marcus Michelangeli, a study co-author. Michael Bertram<\/p>\n

Remarkably, the study found that more of the salmon on benzos made it out to sea than those that were drug-free, perhaps because they were more likely to survive the journey. The clobazam fish also passed through obstacles along the way \u2014 two hydropower dams \u2014 at a faster clip. <\/p>\n

These results highlight a strange irony: Humans have made the world more stressful for all kinds of animals by, for example, destroying their habitat<\/a> and damming up rivers. At the same time, we\u2019re flooding the environment with mood-changing meds. Is that somehow helping them cope? <\/p>\n

Pretty much everywhere<\/a> scientists look for drugs in the water, they find them. Caffeine. Metformin. Antidepressants. Antibiotics. Birth control. Tylenol. Basically, if we use a lot of them, they\u2019re part of aquatic habitats. <\/p>\n

Thankfully, they appear in low enough doses that if you, say, chug a glass of river water those chemicals are not likely to affect you (again, for better or worse). Most fish, however, are much smaller. And previous research shows that these micro-doses can influence them in serious ways.<\/p>\n

A seminal 2007 study<\/a>, for example, showed that small amounts of synthetic estrogen \u2014 a common ingredient in birth control that often makes its way into the environment \u2014 can \u201cfeminize\u201d male minnows. This means they can produce early-stage eggs in their testes, essentially becoming intersex. That ultimately impairs their ability to mate and can, as the study shows, cause fish populations to collapse. <\/p>\n

\"A<\/a><\/p>\n

A fathead minnow. TroutFodder\/Getty Images<\/p>\n

Researchers have also shown<\/a> that male fish exposed to estrogen struggle to build nests and put on courtship displays for females.<\/p>\n

Trace levels of antidepressants, like fluoxetine (Prozac) and sertraline (Zoloft) affect fish behavior, too \u2014 sometimes in bizarre ways. I came across one study<\/a> linking fluoxetine exposure to larger \u201cgonopodium\u201d size. That\u2019s basically a fish penis. The drug can also \u201cincrease male coercive mating behavior,\u201d the authors wrote. <\/p>\n

A study<\/a> on sertraline, meanwhile, suggests the drug can make fish less anxious and more likely to take risks and explore. Some research<\/a> on the benzo oxazepam has similarly been shown to make fish bolder. <\/p>\n

Oh, and I also found some interesting experiments with metformin, which is used to treat Type 2 diabetes and thus one of the most widespread drugs in wastewater. A 2018 paper<\/a> suggests that when Siamese fighting fish \u2014 like the betta fish you can buy at pet stores \u2014 are exposed to levels of metformin that have been found in the environment, they become less aggressive. Fighting fish, fighting less! \u201cSubjects exhibited less aggression toward a male dummy stimulus,\u201d the authors wrote. <\/p>\n

Over the last two decades, scientists have turned up plenty of evidence that drugs in our wastewater alter the lives and behavior of fish (and some other animals<\/a>). The problem is that most of these studies are done in labs, in fish tanks, and not in the wild. So they don\u2019t tell us much about what this means for animals in the real world, many of which are threatened with extinction, including some populations of Atlantic salmon. <\/p>\n

That\u2019s what makes this new study so useful \u2014 and frankly, impressive. <\/p>\n

More drugged salmon make it out to sea<\/p>\n

Atlantic salmon, if I may say, live remarkable lives. They\u2019re born in freshwater streams and then, as young, go through a number of physical transformations<\/a> before migrating to the salty ocean in a process that can cover thousands of miles. After living their lives at sea for a year or more, they\u2019ll swim back up river \u2014 typically in the same river they were born in, relying on some magical-sounding<\/a> navigation skills \u2014 to have babies and produce the next salmon generation. <\/p>\n

Even in historic times, this life was probably stressful. All that travel. Swimming through rivers full of predators. Yikes! Humans have only made it harder. We\u2019ve installed dams that fish have to navigate; there are more than 7,600 dams in Sweden alone. We\u2019ve heated up the ocean and streams, which can deprive salmon of oxygen<\/a>. We fish the hell out of them. And of course, we\u2019ve polluted their habitat. <\/p>\n

Key here is that some of that pollution consists of drugs specifically designed to make humans less anxious. Authors of the new study wanted to figure out whether they might have a related effect on fish \u2014 and importantly, what that means for their arduous journey. <\/p>\n

The researchers\u2019 methods were somewhat bizarre: They collected dozens of young wild salmon from a hatchery along the Dal\u00e4lven, a river in Sweden, and inserted medical implants into their flesh. Some of those implants slowly released drugs \u2014 including the benzo clobazam \u2014 at a level akin to what they might be exposed to in the wild. (The researchers didn\u2019t detect clobazam in this particular river.) Other implants were essentially placebos, meaning they didn\u2019t release anything. <\/p>\n

The team also performed surgeries on the fish to insert miniature devices that emit sound; those sounds can be picked up by underwater microphones that were placed along the river to track each individual fish. (How do you do surgery on a fish? You sedate it and run water over its gills while you\u2019re operating.)<\/p>\n

Then they released the fish back into the river \u2014 which has two hydropower dams downstream \u2014 and tracked their journey to sea. <\/p>\n

\"A<\/a><\/p>\n

A dam in the Dal\u00e4lven River. Rebecca Forsberg<\/p>\n

As they discovered, the fish drugged with clobazam were more likely to make it to sea compared to those that were drug-free. It\u2019s likely that more of the undrugged salmon died on their journey or were otherwise slowed down, said Jack Brand, the study\u2019s lead author and a researcher at the Swedish University of Agricultural Sciences. <\/p>\n

This might be because the benzos made the fish less social \u2014 less likely to school in the face of predators \u2014 and more likely to take risks, he said. Those traits can be helpful for navigating downstream. Solitary fish tend to move faster, Brand told me. And with benzos in their system, they may be less afraid to swim through a dam. <\/p>\n

\u201cThese drugs can be used in humans as anti-stress drugs,\u201d Brand said. \u201cYou can imagine passing through a hydropower dam \u2014 these are big dams with big turbines \u2014 is a fairly stressful event for a small fish. And usually what you find is that lots of predators hang around these areas. Maybe it\u2019s helping the fish recover from stress faster.\u201d<\/p>\n

Outside experts I talked to mostly agree with his interpretation \u2014 that the clobazam likely made the fish less risk-averse. \u201cIt probably was because they were more bold than the other fish, which were kind of shy and hanging together,\u201d said James Meador, an affiliate professor at the University of Washington who has spent years studying how pollutants affect fish. He was not involved with the research. \u201cEven in the presence of predators, I guess they really weren\u2019t too concerned.\u201d <\/p>\n

This is pretty wild to think about. When these fish encounter stressful situations, trace levels of human anti-anxiety medications \u2014 which are, to be clear, pollution \u2014 may be sort of chilling them out. So, drugs: good? <\/p>\n

Are drugged salmon better off? <\/p>\n

At face value, it seems like a little dose of clobazam can help these fish out with their stressful lives, not unlike it may do for some of us.<\/p>\n

But, as I was told, that is very clearly the wrong takeaway. <\/p>\n

\"A<\/a><\/p>\n

Salmon leap out of the water in the Ettrick, a river in Scotland. Jeff J Mitchell\/Getty Images<\/p>\n

\u201cWe think that any changes to natural behavior are likely to have potential negative consequences,\u201d Brand said.<\/p>\n

Fish on clobazam are less likely to school, or group together, which is an anti-predator response. So even though they appear better at navigating the river \u2014 and less likely to be eaten during their seaward migration \u2014 it\u2019s possible that they may be more prone to getting killed at sea. We just don\u2019t know. (Some past research<\/a> shows that young salmon exposed to a much higher dose of a different benzo \u2014 oxazepam \u2014 were more likely to be eaten by predators during their downstream migration.)<\/p>\n

\u201cThe definition of pollution is that it causes harm,\u201d said Karen Kidd, an ecotoxicologist at McMaster University in Canada who was not involved in the new Science study. \u201cThere are still many unknowns, such as whether it influences their survival in the ocean or their ability to return to spawn in the river as adults.\u201d<\/p>\n

In other words, while it\u2019s not clear exactly how clobazam is shaping salmon populations, it is influencing the complex behavior of a species \u2014 and its relationships in a food web balanced by millennia. That alone is cause for concern: It\u2019s another way we\u2019re messing with nature. And clobazam is just one of the thousands of prescription drugs worldwide. <\/p>\n

That leads me to the last point: We\u2019re pumping out more and more<\/a> chemicals every year and scientists still don\u2019t understand how most of them \u2014 there are tens if not hundreds of thousands<\/a> \u2014 affect the natural world. <\/p>\n

\u201cIf society values clean water, then we need to understand the consequences of chemicals that we put in the natural world,\u201d said Bryan Brooks, an environmental scientist at Baylor University, who was not involved with the new research. The bottom line, he added, is that \u201cif we put stuff in the environment, we need to understand what happens to it.\u201d<\/p>\n

Today roughly a quarter of freshwater wildlife<\/a> is in decline and at risk of extinction. Most of the threats they face are visible \u2014 dams, the destruction of habitat, invasive species. Our drugs are almost certainly another serious threat, though it\u2019s one we can\u2019t see and poorly understood.<\/p>\n

\u201cPharmaceutical pollution, or chemical pollution in general, is really this invisible agent of global change,\u201d Brand said. \u201cIt\u2019s probably posing a greater risk than at least what the public acknowledges. This is a potentially significant threat to our aquatic wildlife.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"For those of us with anxiety (hello!), the class of prescription drugs known as benzodiazepines, or benzos, can…\n","protected":false},"author":2,"featured_media":10408,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4317],"tags":[7029,7175,105,218,16,15],"class_list":{"0":"post-10407","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-mental-health","8":"tag-climate","9":"tag-down-to-earth","10":"tag-health","11":"tag-mental-health","12":"tag-uk","13":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/114318614482101058","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/10407","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=10407"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/10407\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/10408"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=10407"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=10407"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=10407"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}