Research finds that fish are capable of having depression

Published 12 months ago - 2

We’ve all seen those sad looking zoo animals – the monkey who sits in its enclosure and stares at nothing, the lion that paces back and forth, the bird with patchy feathers. They don’t seem totally healthy or mentally present. You could even say they seem depressed.

Your goldfish who floats aimlessly in his bowl could be in the same boat.

Current research being conducted at Alabama’s Troy University, suggests not only that fish are capable of being depressed, but also that studying depression in fish could help further understanding of this mental health issue in humans and aid in the development of anti-depressant drugs.

But humans are so complex, a simple fish couldn’t help us discover something about ourselves, right?

Dr. Julian Pittman, who is spearheading this project, disagrees. “The neurochemistry is so similar that it’s scary.” We have more in common with them than you think, and “there is a lot we don’t give fish credit for.” (For example, some fish have been found to use tools and are even capable of recognizing different people’s faces) However, the most obvious difficulty in studying an animal is that you cannot ask them how they feel.

Instead, you must rely on behavioral cues in order to draw conclusions about their mental state. Pittman, a professor in the Biological and Environmental Sciences department, uses the “novel tank test” to assess depression in zebra fish.

Just like depressed humans, a depressed fish is withdrawn and listless. A mentally healthy fish will zip around a new tank, actively exploring the entirety of the area. A depressed fish will spend most of its time in the bottom half of the tank, floating there without showing exploratory activity. The amount of time that the fish spends in the top or bottom half directly relates to their mental state.

??? whole weeks, then abruptly stopped giving it the alcohol to cause withdrawal symptoms. These fish would consistently hang around in the bottom of their new tank, not moving much and just drifting. However, after being treated with an antidepressant, the previously depressed fish would be back to swimming at the surface within two weeks.

This is one of the reasons why Pittman likes these fish: they show clear indications of their mental state; previous studies on mice don’t have the same power because their behavioral cues lack the clarity found here.

Skeptics may not believe that a fish can relate to a human in any way, and its true that they can’t capture the full complexity of a person’s mental health, but they can provide smaller insights, which in turn become larger discoveries.

There is some debate over whether depression is the correct word. Some scientists believe anxiety is a better fit.

A biologist in Australia, Culum Brown, has extensively researched the behavior of fish and has total faith in a fish’s feelings. “You can tell. Depressed people are withdrawn. The same is true of fish.”

They lose interest in toys, in food, much like clinically depressed people do. For fish, the fix for their depression is much simpler. Usually, it is a result of under stimulation. A bored fish, with nothing to do in its tank is a depressed fish. Keeping your goldfish in a small bowl is a sure recipe for unhappiness – besides the low levels of oxygen, there’s not much room for exploring. Doctor Victoria Braithwaite of Penn State suggests placing new items in the tank and moving them around from time to time to provide a more complex environment for a fish to live in.

So the next time you see a fish drifting near of the bottom of its bowl, tape some pictures to the glass or add some interesting objects and tell it that you know how it feels.

Aerin Toskes, a senior, studies environmental science. She is a staff writer for Le Provocateur.

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