Putting Fish on Psychoactive Drugs

One imagines that pharmaceutical researchers mostly test their products on rodents and other mammals. But, can we learn anything by testing them on, for example, fish?

No one knows what to make of the new studies about how psychoactive medication affects fish, but surely it has considerable entertainment value.

Writing in Bloomberg Businessweek Drake Bennett grasps the humor in it all:

It’s not news that human beings dump a lot of stuff into lakes and rivers. The evidence is all around us—massive blooms of algae from fertilizer runoff, stunted fish and dead waterfowl from mine tailings, and oil spills. But that is stuff we’re used to thinking about as pollution, and they’re the sort of effects—die-offs and deformity—that we’re used to worrying about. What about the stuff we actually put into our own bodies? What effect does that have when it gets out into the world? And what happens to a species—or, for that matter, an entire ecosystem—when we put it on drugs?

Environmentalists are up in arms about industrial pollutants. Are they asking themselves what happens when we pollute the ecosystem with the psychoactive medications that we are taking to keep ourselves in just the right mood?

To study the issue, Swedish researchers found a way to measure what anti-anxiety medication does to fish, in particular to perch.  In particular, they chose oxazepam, a member of the benzodiazepam family. Oxazepam belongs to the same family as Valium.

When perch were exposed to the drug, the following occurred:

Even at dosages at the lower end of what they found in the wild, the fish in the oxazepam tanks were less social than those in the control tanks. The drugged fish put more distance between themselves and other fish, and they ate faster than normal. At higher dosages, the researchers also found an increase in what they termed “boldness,” the lack of hesitation with which the fish entered an unfamiliar area.

So, oxazepam makes fish more anti-social, makes them eat very quickly and disinhibits them. It makes some sense, people who eat very quickly are not very social.

As might be expected, the drug suppresses the fish’s normal anxiety mechanism and thus makes it more oblivious to dangers. If anxiety signals danger, then suppressing it will lead people and fish to court greater danger.

A fish that takes a little too much oxazepam is more likely to become bait. It is reasonable to ask whether these medications produce a similar effect on human beings. When people take anxiolytics are they more likely to behave recklessly? It makes sense to think that they dol.

The researchers consider some of the changes in perch behavior to be positive. They note:

The fish feed at a faster rate, they become more active. “They actually perform better,” he said. For perch, at least, putting oxazepam in a river is a bit like putting Adderall in the water supply of a college dorm (or cocaine in Charlie Chaplin’s salt).

I hope that the Swedes do not really mean to say that it is a good thing to put a dorm full of college students on Adderall.

They do note that when it comes to the ecosystem, eating faster is not necessarily an unalloyed good:

The plankton that perch eat in turn eat algae, and if the perch ate up all the plankton the algae would run rampant, choking off the rest of the life in the area.

But then, you are surely asking, what about Prozac? What effect does it have when introduced to the water supply? Rebecca Klaper, from the University of Wisconsin put Prozac to the fish test:

She found that fluoxetine [Prozac] in the water didn’t affect the females, but made the males essentially obsessive-compulsive (a condition, interestingly enough, that Prozac is prescribed for in humans). The males spend an unusual amount of time building their underwater nests. When the amount of fluoxetine was increased, the males started ignoring the females. When the dosage was increased still further, the males killed the females.

It is interesting that Prozac makes fish more obsessive-compulsive, especially since it is prescribed for that condition. One wonders if the reaction correlates with the way that amphetamines work to treat hyperactivity.

And, what to make of the fact that Prozac makes male fish hostile and aggressive toward female fish? Does an increased serotonin level make men feel more masculine, even when they have not done anything to justify the feeling? Do they show it off by being hostile to women?

Does Prozac produce macho men? It’s worth considering.