Quirk

Excerpt from Quirk

NEUROTICISM FACET:
DEPRESSION

DEPRESSION QUESTIONS Rarely                          Sometimes                  Often

I can’t get motivated:

Little things get me down:

The glass is half empty:

This gives you a quick look at where you land on this facet. If your answers tend toward the “often” side, you’re higher in that facet.

The depressive personality has a tendency to look on the bleak side. If you score high on depression, then you may tend toward the skeptical, solitary, and slow-moving end of this personality measure. That doesn’t mean you’re always blue. You just aren’t going to be voted “most lively and optimistic.”

If your score is mid-range, you might not always think that you, or the world, are in great shape, but neither are you hanging your head like Eeyore. If your score leans toward “rarely,” then you probably have a solid respect for yourself, you feel motivated, successful, cheerful, and you’re eating and sleeping like a champ.

Then again, Klaus-Peter Lesch, whose mouse lab I visited in Germany, isn’t so sure there is such thing as “real” depression. He’s met plenty of people who feel hopeless, lifeless, and spiritually spent. Both he and his wife treat these patients in the psychiatric hospital downhill from his office. Sometimes they can give a patient a pill, and drive the gloomy feelings away. But other times they try pills, and talk therapy, and different pills, and still the patient suffers.

“I don’t believe any two patients have the same depression,” he proposes. “Depression is a group of disorders. There could be 100 or 150 disorders within the framework of depression.”

Wow. That raises an interesting problem, doesn’t it? The people who study the biology of personality are discovering that we’re too complicated to describe. And yet, the best tool psychologists have to diagnose us is a very simple list of descriptions. The famous DSM (Diagnostic and Statistical Manual), the book that tells you whether you’re officially off the rails, is not based on scientific research. It is not based on discoveries about serotonin and genes and neurons. It’s not even based on studies of huge numbers of people, which might have revealed subtle patterns. First published in 1952, and based on an Army manual, the DSM creates, out of thin air, names for the various ways a human personality can go haywire. The scientific basis of these invented categories is… well, it’s mainly based on how psychiatrists view their patients. So it’s really not very scientific.

And that makes it difficult to come up with a logical treatment plan for depressed people. Talk therapy works for some, but not all, people. Serotonin drugs work for about half. Some people recover spontaneously, others never rise from depression. Clearly, we don’t understand this disorder very well. So we look to the mice.

DEPRESSIVE MOUSE

Because human depression is so poorly understood, scientists have created oodles of depressed mice. It’s instructive that this is even possible. That there are so many ways to lower the energy level of a brain tells us a couple of things: One, it may be a common condition in wild animals. Two, as such, it’s probably not a dire, horrible fate.

But first things first: Given our confusion over what depression is, how would you know if you succeeded in creating a legitimately depressed mouse?

Just as the elevated-plus maze is a standard measure of mouse anxiety, the forced swim and the tail suspension are common tests of murine moroseness.

For the first, a researcher lowers a mouse into a beaker of water. The mouse swims around the beaker for a while. She might try to power herself up the side of the glass. She will probably poop a few times. (Mice do that for any new experience. Mitzi and Maxi used to do it when I handled them.) But after just a few minutes the average mouse will quit. She’ll float quietly. (She will not drown. Mice are expert little swimmers, and can paddle for two and a half hours. They’re also good floaters. When they stop swimming their faces rest above water and they appear calm.)

Regardless of how it appears, researchers categorize the floating as “despair behavior.” I expect this is a misnomer, since despere is Old French for “lose hope.” Hope implies a sense of the future. Mice aren’t likely to have a sense of the future, hopeful or otherwise. They live in the moment. And if at the moment they are stuck in water, then que sera, sera. Given razor blades, they wouldn’t slit their little wrists because they don’t realize that their future is bleak. So the term “acceptance” might fit better than despair. Whatever you call it, the mice who quickly substitute floating for swimming are considered to be depressive, and therefore useful for research.

To conduct the “tail suspension test,” a researcher sticks tape to a mouse’s tail then hangs the animal from a tiny scale. The scale records the mouse’s struggle to get free over the course of six minutes. To minimize distractions, this experiment often takes place inside a small, white cubicle, with data flowing out to a hungry computer. (I admit I don’t like lifting Mitzi and Maxi by their tails, but it really does seem to be fine. Veterinarians do it. Even people who run web sites dedicated to pet mice do it. I can find no indication, anywhere, that it hurts them. In fact, they use their tails as some monkeys do, gripping with it as they climb. But lifting them by the tail just seems rude.) As with the “forced swim,” it’s the time a mouse spends hanging motionless that scientists measure. The ones who cease struggling soonest are the ones you want to test drugs on.

So that’s how scientists determine if a mouse is depressed. The forced swim and the tail suspension tests are the most common in part because they are the least distressing to mice.

If that were the only indication of mouse “depression,” I would have my doubts. It seems to me that the first mice to quit swimming could also be considered the most conservative ones. Accepting that their environment is currently impossible to conquer, these mice save their energy. When their environment changes, they’ll have the strength to resume their tasks.

But the whole point of creating depressed mice is to find drugs that combat depression in people. So what happens when you feed a despairing mouse a nibble of serotonin drug? She swims longer before conceding to her environment, and wriggles longer when hung by her tail. This is reassuring. It means a mouse is on the right track. It can be used to try out new drugs that have fewer side effects, or a greater success rate.

What, then, do the legions of despairing mice tell us about our own personalities?