Why These Salmon Are On Anxiety Meds

Summary

Short Wave Podcast Episode Summary

Title: Why These Salmon Are On Anxiety Meds
Host: Emily Kwong
Guest: Jonathan Lambert, NPR Science Reporter
Release Date: April 23, 2025

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1. Introduction

In this episode of Short Wave, hosted by Emily Kwong and featuring NPR science reporter Jonathan Lambert, the discussion centers around an intriguing and somewhat alarming intersection of human pharmaceuticals and aquatic life. The episode delves into how anti-anxiety medications are making their way into salmon populations and the broader implications of pharmaceutical pollution in waterways.

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2. Pharmaceutical Pollution: How Salmon Get on Anxiety Meds

Jonathan Lambert explains the primary pathway through which pharmaceuticals enter aquatic ecosystems:

Jonathan Lambert [00:58]: "Basically through us. So when humans take medication, like for anxiety or bacterial infections, our bodies don't use all of it, and we end up peeing out some of the chemicals that can end up in wastewater, which can get into rivers and streams."

Lambert highlights that more than 900 different pharmaceutical ingredients have been detected in waterways globally, underscoring the pervasiveness of this issue.

Jonathan Lambert [01:27]: "Researchers have found more than 900 different pharmaceutical ingredients in waterways around the world."

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3. Effects of Anti-Anxiety Drugs on Salmon Behavior

The conversation shifts to the direct impact of these drugs on fish behavior. Laboratory experiments have shown that exposure to anti-anxiety medications alters how fish interact and take risks.

Jonathan Lambert [01:49]: "If researchers give fish, say, a benzodiazepine like Xanax or an SSRI like Sertraline, in the lab, these fish become more antisocial and more prone to take risks."

These behavioral changes raise concerns about how such alterations could affect survival and ecosystem dynamics in the wild.

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4. The Swedish Field Study: Design and Findings

Jonathan Lambert introduces a pivotal study conducted by biologist Jack Brand at the Swedish University of Agricultural Sciences. Published in the journal Science, the study represents one of the first field experiments to assess the real-world impact of pharmaceuticals on salmon.

Study Design:

• Subjects: Over 250 juvenile hatchery-raised Atlantic salmon.
• Interventions: Slow-release capsules implanted in salmon, releasing two drugs:
  • Clobazam: A benzodiazepine used to treat anxiety.
  • Tramadol: An opioid used for pain management.
• Control Groups: Four treatments—no drug, only clobazam, only tramadol, and both drugs.
• Tracking Method: Acoustic tags emitting sounds detected by receivers along the migratory route to monitor the salmon's journey from a Swedish river to the Baltic Sea.

Jonathan Lambert [05:33]: "So the researchers wanted to see if combining them had like extra bad effects."

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5. Unexpected Benefits and Hidden Dangers

The results of the study were surprising. Contrary to expectations, the anxiety medication clobazam appeared to enhance the salmon's migration success.

Emily Kwong [06:35]: "It was a bit of a surprise. So one drug, the pain medication, didn't seem to make any difference, but it turned out that fish exposed to clobazam were actually more successful in reaching the Baltic Sea than salmon who weren't exposed."

However, this apparent benefit masks deeper issues. Further analysis revealed that clobazam-exposed salmon migrated two and a half to three times faster than their unmedicated counterparts. While this might seem advantageous, it led to antisocial and risk-prone behavior, making the fish more vulnerable to predators once they reached the ocean.

Jonathan Lambert [08:57]: "Clobazam essentially made them more antisocial and willing to live a bit more dangerously."

This duality illustrates the complex and often unintended consequences of pharmaceutical pollution.

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6. Broader Implications of Pharmaceutical Pollution

Jonathan Lambert expands the discussion to the global scale, emphasizing that the study's focus on clobazam is just the tip of the iceberg.

Jonathan Lambert [09:48]: "We have no idea what those anti anxiety medications, plus the analgesics, plus the antibiotics, plus the antiepileptics, plus the chemotherapeutants, et cetera, et cetera, collectively are doing to fish and other aquatic species."

Ecotoxicologist Karen Kidd underscores the uncertainty surrounding the combined effects of various pharmaceuticals, describing it as a "huge unknown."

Karen Kidd: "You think of the soup of pharmaceuticals that are going into our rivers, that's a huge unknown."

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7. Possible Solutions to Pharmaceutical Waste

Addressing this environmental challenge requires multifaceted solutions. Jonathan Lambert outlines several strategies to mitigate pharmaceutical pollution:

1. Enhanced Wastewater Treatment: Upgrading facilities to more effectively filter out pharmaceutical compounds. Lambert notes that pollution is often worse in low to middle-income countries due to inadequate wastewater management infrastructure.

2. Designing Greener Pharmaceuticals: Developing medications that are as effective in humans but degrade more easily in the environment. This concept aligns with existing trends in "greener" consumer products.

Emily Kwong [10:51]: "Better filtration systems. What else, John?"

Jonathan Lambert [10:55]: "There's also a push to design greener drugs, basically tweaking pharmaceuticals to degrade more easily in the environment, but still be just as effective in humans."

While these measures aren't comprehensive solutions, they represent critical steps toward reducing the environmental footprint of pharmaceuticals. Lambert emphasizes the importance of these actions in the context of broader ecological challenges like climate change and habitat destruction.

Jonathan Lambert [11:05]: "And with climate change and habitat destruction already majorly disrupting animal lives, it's important to try to do what we can to ensure our waste isn't disrupting their behavior too."

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8. Conclusion

The episode concludes by highlighting the significance of the Swedish study as a groundbreaking step in understanding the real-world impacts of pharmaceutical pollution on aquatic life. However, it also acknowledges the vast unknowns that remain, particularly concerning the synergistic effects of multiple pharmaceutical compounds.

Emily Kwong [11:30]: "John Lambert Another incredible science story. Please come back anytime. Thank you so much."

The conversation between Emily Kwong and Jonathan Lambert serves as a compelling call to action for better environmental stewardship concerning pharmaceutical waste, urging both consumers and policymakers to consider the far-reaching impacts of our medication use.

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Notable Quotes with Timestamps

• Jonathan Lambert [00:58]: "Basically through us. So when humans take medication, like for anxiety or bacterial infections, our bodies don't use all of it, and we end up peeing out some of the chemicals that can end up in wastewater..."

• Jonathan Lambert [01:27]: "Researchers have found more than 900 different pharmaceutical ingredients in waterways around the world."

• Jonathan Lambert [01:49]: "If researchers give fish, say, a benzodiazepine like Xanax or an SSRI like Sertraline, in the lab, these fish become more antisocial and more prone to take risks."

• Emily Kwong [06:35]: "It was a bit of a surprise... fish exposed to clobazam were actually more successful in reaching the Baltic Sea than salmon who weren't exposed."

• Jonathan Lambert [08:57]: "Clobazam essentially made them more antisocial and willing to live a bit more dangerously."

• Karen Kidd [09:48]: "You think of the soup of pharmaceuticals that are going into our rivers, that's a huge unknown."

• Jonathan Lambert [10:55]: "There's also a push to design greener drugs, basically tweaking pharmaceuticals to degrade more easily in the environment..."

---

This episode of Short Wave provides an enlightening exploration of an emerging environmental issue, blending scientific investigation with ecological concern. It invites listeners to reflect on the unintended consequences of human actions and the need for innovative solutions to safeguard our natural ecosystems.

Transcript

[Amazon One Medical]

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[Emily Kwong]

Amazon One Medical, you're listening to Short Wave from npr. Hey, short waivers. Emily Kwong here. And today I am joined by NPR science reporter Jonathan Lambert. Hey, John.

[Jonathan Lambert]

Hey, Emily.

[Emily Kwong]

John, I must thank you for all the hilarious and fascinating science stories you've been bringing us lately. Like chimps contagiously peeing or iguanas sailing the high seas. Or this most recent banger, salmon on drugs. What's that about?

[Jonathan Lambert]

Yeah, salmon on drugs. Specifically anti anxiety drugs.

[Emily Kwong]

How are salmon getting a hold of. Not that they have hands, but how are they getting a hold of anti anxiety pills?

[Jonathan Lambert]

Basically through us. So when humans take medication, like for anxiety or bacterial infections, our bodies don't use all of it, and we end up peeing out some of the chemicals that can end up in wastewater, which can get into rivers and streams. And runoff from pharmaceutical factories gets into waterways, too. All told, researchers have found more than 900 different pharmaceutical ingredients in waterways around the world.

[Emily Kwong]

900 different ingredients. That's a lot.

[Jonathan Lambert]

Yeah.

[Emily Kwong]

Well, how does this then affect the fish and other aquatic creatures?

[Jonathan Lambert]

We're not entirely sure. Scientists have been trying to figure out what all this pollution could be doing to fish, and most of that has been done in the lab. Those experiments have shown that giving fish anxiety meds, for instance, kind of messes with their behavior.

[Emily Kwong]

How so? Like when researchers give fish medicine on purpose, what happens?

[Jonathan Lambert]

Yeah, so if researchers give fish, say, a benzodiazepine like Xanax or an SSRI like Sertraline, in the lab, these fish become more antisocial and more prone to take risks. But it's hard to say how these drugs affect their behavior. Out in the wild.

[Amazon One Medical]

We can't, you know, dump a bunch of pharmaceuticals into the river.

[Jonathan Lambert]

That's Jack Brand. He's a biologist at the Swedish University of Agricultural Sciences, and he worked on a study that kinda did the next best thing from a scientific perspective.

[Emily Kwong]

Okay.

[Jonathan Lambert]

The study was published in the journal Science this past month. The team implanted pharmaceuticals in Atlantic salmon in Sweden and monitored how two drugs, an anxiety med and a pain med, influenced their migration behavior.

[Emily Kwong]

I'm so curious. What happened?

[Jonathan Lambert]

Something kind of unexpected. The anxiety medication actually improved the migration success of the salmon.

[Emily Kwong]

Wait, so the drugs helped?

[Jonathan Lambert]

In this narrow sense, yeah, they did seem to help. But that's not the whole story.

[Emily Kwong]

Okay, so today on the show, how scientists managed to drug salmon in the wild. What pharmaceutical pollution could be doing to.

[Jonathan Lambert]

Aquatic animals worldwide and what we can do about it.

[Emily Kwong]

You're listening to shortwave, the science podcast from npr.

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[Emily Kwong]

Okay, John, so let's back up a second. Because pharmaceutical drugs are designed to work on human brains and bodies, right? So how do they end up affecting the brains and bodies of fish?

[Jonathan Lambert]

Yeah, so it turns out a lot of drugs that act on our minds target parts of the brain that have a deep evolutionary history and so they're shared by lots of different animals.

[Emily Kwong]

Mm. Okay.

[Jonathan Lambert]

So they can work on salmon in similar ways that work on humans. Now it's not like fish are literally popping pills like we would. What's happening is the pills are getting super diluted rivers and entering their bodies through their gills.

[Emily Kwong]

Oh. Huh.

[Jonathan Lambert]

Yeah. But even with super low concentrations, like what a fish would encounter in the wild, these drugs are still altering their behavior in the lab.

[Emily Kwong]

This all makes sense. It sounds like a big problem. So there have been a lot of experiments to understand the problem on a deeper level, but way fewer field experiments. So how are researchers studying the effects of drug exposure in the wild?

[Jonathan Lambert]

So researchers put these like slow release capsules into the bodies of over 250 juvenile hatchery raised Atlantic salmon. The capsules released two drugs. A benzodiazepine called Clobazam used to treat anxiety and an opioid used for pain management called Tramadol.

[Emily Kwong]

So why these two drugs, Clobazam and Tramadol in particular?

[Jonathan Lambert]

In humans, these drugs can cause harmful interactions. And so the researchers wanted to see if combining them had like extra bad effects.

[Emily Kwong]

Yikes. Okay.

[Jonathan Lambert]

They're also found in lots of rivers around the world, but not in the river where these particular salmon live.

[Emily Kwong]

Okay, so this sounds like a very good river in which to conduct this study.

[Jonathan Lambert]

Yeah, yeah, exactly. Overall, they had four different treatments. No drug, only clobazam, only tramadol, and both.

[Emily Kwong]

Okay, well, what did they do next?

[Jonathan Lambert]

They also implanted these tracking devices so the scientists could follow the fish as they migrated from a release site in a Swedish river out to the Baltic Sea.

[Emily Kwong]

So they put like GPS on the fish?

[Jonathan Lambert]

Not exactly. They were like little devices that emit a sound. And then the researchers placed a bunch of receivers along the migratory route that pick up that sound, allowing them to kind of like reconstruct the journey.

[Emily Kwong]

Oh, so it's like air tags for salmon?

[Jonathan Lambert]

Yeah.

[Emily Kwong]

All right, so they have these experimental conditions. They have the salmon trackers. What did they find?

[Jonathan Lambert]

It was a bit of a surprise. So one drug, the pain medication, didn't seem to make any difference, but it turned out that fish exposed to clobazam were actually more successful in reaching the Baltic Sea than salmon who weren't exposed.

[Emily Kwong]

Interesting. Let's break this down a little bit. Why would an anti anxiety drug like clobazam make fish better at migrating?

[Jonathan Lambert]

Yeah, the researchers aren't 100% sure, but one part of their results hints at an answer. So this route, this migration route is not exactly like a lazy river. There are two hydropower dams, each with a series of turbines that the fish have to cross to get to their destination. Those can be pretty hairy. Here's Olivia Simons, a salmon biologist at the Norwegian Institute for Nature Research.

[Emily Kwong]

Basically, with turbine passage, you can get injuries which are of course not good if you have a long way to swim, but you also get mortality. So if they're struck by a blade, they can die. So that's not good. It's tough out here being a salmon.

[Jonathan Lambert]

Yeah. So non drugged fish really took their time navigating these dams. Like I imagine them waiting together in a group and going, oh, not yet. Wait, wait. Okay. But the clobazam exposed fish did it two and a half to three times faster.

[Emily Kwong]

Those drugged fish were like, I'm ready.

[Jonathan Lambert]

Yeah, yeah. Here's how Brand explained it.

[Amazon One Medical]

So we actually found that more clobazam exposed fish eventually migrated through the river and reached the Baltic Sea. Their destination more than unexposed fish.

[Emily Kwong]

Poor salmon friends. So the anti anxiety meds made those salmon, you know, I guess migration risk takers. But it left those unmedicated salmon behind.

[Jonathan Lambert]

Yeah. On the face of it, it kind of seems like this study is basically saying that it's good to give salmon benzos, but the authors caution against that interpretation.

[Emily Kwong]

Yeah, I imagine that taking more risks might help fish reach the Baltic Sea faster, but it could pose problems once they get there.

[Jonathan Lambert]

Exactly. A follow up lab experiment they did found that Clobazam made salmon less likely to shoal with other salmon. Shoaling is when fish group together for a safety in numbers kind of thing. And setting off on your own could make it easier for ocean predators to pick you off.

[Emily Kwong]

Yeah. Lone wolf, lone salmon behavior.

[Jonathan Lambert]

Yeah. Clobazam essentially made them more antisocial and willing to live a bit more dangerously. Scaled up a lot more antisocial and risk prone salmon could ultimately shrink the population and that could cause problems for the whole ecosystem.

[Emily Kwong]

Now, John, migration is just one part of the Atlantic salmon's life cycle. Right. So how else do the drugs affect them?

[Jonathan Lambert]

Yeah, so it's honestly a little bit of a limitation of this study in that it's just looking at this kind of narrow slice of an animal's life. Showing that drugs can influence behavior in the wild was still a huge accomplishment, but there are still a lot of unknowns.

[Emily Kwong]

Right. Clobazam is just one drug. But you said earlier that over 900 different pharmaceutical ingredients have been found in rivers and streams worldwide.

[Jonathan Lambert]

Yeah, exactly. Here's what Karen Kidd, an ecotoxicologist at McMaster University, had to say. You think of the soup of pharmaceuticals that are going into our rivers, that's a huge unknown. We have no idea what those anti anxiety medications, plus the analgesics, plus the antibiotics, plus the antiepileptics, plus the chemotherapeutants, et cetera, et cetera, collectively are doing to fish and other aquatic species.

[Emily Kwong]

Yeah, absolutely. So is there anything we can do as consumers or just as a society about pharmaceutical pollution that doesn't, you know, require people to stop taking drugs that make their lives better?

[Jonathan Lambert]

Yeah, there definitely are things we can do. One way is by designing wastewater treatment plants that do a better job filtering out drugs. A study from a few years ago actually found that pharmaceutical pollution in rivers is often worse in low to middle income countries because wastewater management infrastructure there doesn't catch it all.

[Emily Kwong]

Interesting. Okay, so better filtration systems. What else, John?

[Jonathan Lambert]

There's also a push to design greener drugs, basically tweaking pharmaceuticals to degrade more easily in the environment, but still be just as effective in humans.

[Emily Kwong]

That's so interesting because. Right. There's like greener cleaning products out there. Greener makeup products, greener medicine could totally be a thing.

[Jonathan Lambert]

Yeah, yeah. And these solutions aren't silver bullets, but they could lessen our impact. And with climate change and habitat destruction already majorly disrupting animal lives, it's important to try to do what we can to ensure our waste isn't disrupting their behavior too.

[Emily Kwong]

John Lambert Another incredible science story. Please come back anytime. Thank you so much.

[Jonathan Lambert]

Thank you.

[Emily Kwong]

This episode was produced by Hannah Chin and edited by me, Emily Kwong and Rebecca Ramirez. Tyler Jones checked the facts, Kwesi Lee was the audio engineer, Beth Donovan is our senior director, and Colin Campbell is our senior Vice President of Podcasting strategy. I'm Emily Kwong.

[Jonathan Lambert]

And I'm Jonathan Lambert.

[Emily Kwong]

Thank you for listening to Shortwave, the science podcast from.

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