Manufacturing depression (2 page)

Twarog, unlike Pavlov, had the benefit of a discovery made in 1921 by a German scientist, Otto Loewi. Loewi wondered exactly how nerves signaled muscles—in particular, whether the process was purely electrical or somehow mediated by chemicals. He claimed that an answer came in a dream
on Easter night
. He sprang out of bed and rushed to his lab, where he cut the hearts out of two frogs and bathed them separately in salt water. Dissected hearts in saline will continue to beat, and Loewi had left intact the nerves that control the pulse rate—the vagus nerve, which slows it, and the accelerator nerve, which does what you think it does. He sent an electric charge from a battery into the vagus nerve; the heart slowed, just as he expected. But then he took the salt water from that bath and dripped it into the other heart’s solution. When that heart slowed without any electrical stimulation, Loewi concluded that a chemical released from the vagus nerve and into the saline, and not electricity, had slowed down the heart. He repeated the experiment on the accelerator nerve, with the same result, and by 5:00 a.m. on Easter Monday had proved the principle of chemical neurotransmission.

By the time Twarog became intrigued by her mussels, Loewi’s principle had been firmly established, but most scientists had settled
into the belief that Loewi’s chemicals—acetylcholine and epinephrine—were the only two neurotransmitters in the body. Twarog, however, was sure that there had to be another—the one that the mussel used to lock and unlock its shell—and she had a hunch that it was the chemical Abbott had sent.

In May 1952, Twarog and Welsh laid out the mussels on a lab bench. As soon as Abbott’s serotonin hit them, the byssus retractors retracted. Twarog was right. Serotonin was the missing neurotransmitter.

As disturbing as the news of a new neurotransmitter might have been to scientific orthodoxy, Twarog’s next idea was downright heretical. She said that serotonin would be found in the mammalian brain, which meant, of course, the human brain. At the time most biologists believed that humans were different from the rest of the animal kingdom, and the brain different from the rest of the body. In particular, they thought that electrical signals leapt around the brain like sparks, a throwback perhaps to René Descartes’ idea that the pineal gland sent out ethereal messengers bearing the soul’s instructions to the body.

Twarog thought this kind of reasoning was “sheer intellectual idiocy.” It didn’t make scientific sense—“what was the difference really between the brain and the rest of the body?” she says, still incredulous after all these years. “This is how nerves worked, no matter where they are.” And, maybe more important, it didn’t make philosophical sense either. “You know Tennyson’s poem ‘Flower in the Crannied Wall’?” She quoted from memory: “‘Little flower—but if I could understand / What you are, root and all / and all in all, I should know what God and man is.’ This is how it had to be.”

Two years later, Twarog moved to Ohio to follow her husband to a university job. Restless, she applied for a position with Irvine Page, a Cleveland Clinic doctor who was trying to understand the role of serotonin in regulating blood pressure. On the day of her interview, it was pouring rain and, she recalls, “I looked like something the cat had dragged in.” Still dripping on Page’s floor, Twarog
described her ideal job: a lab, an assistant, and the time to study the distribution of serotonin in the brain. He grilled her—after all, her hypothesis went against everything he’d been taught about the nervous system—but finally agreed to give her the bench space and a technician. Within a year, she had found serotonin in the brains of rats, dogs, and monkeys.

Twarog’s first paper
—the one about her experiment at Harvard—didn’t get published until 1954. She didn’t even hear back from the editor of the
Journal of Cell Physiology
—Detlev Bronk, the president of Johns Hopkins University—until John Welsh, the Harvard professor, called to inquire about the status of the article. Bronk told him that he wasn’t about to ask his peers to review a speculative article by an unknown girl on such an important topic. While the paper was moldering on Bronk’s desk, other scientists, much more prominent than Twarog, were arriving at a similar conclusion about serotonin. Once they had published their findings, it was safe for Bronk to let the girl have her say.
Her paper with Irvine Page
on cerebral serotonin also had to wait until the big boys said it first. But today no one disputes that she was the first with both discoveries.

Betty Twarog soon returned to marine biology, her first love. But many of the others went on to figure out the biology of neurotransmission, establishing within a decade that electricity really didn’t fly from neuron to neuron like angels, that the brain really ran on chemicals like the rest of the body. And more than a half century later, new neurotransmitters are still turning up under the microscope, the subtleties of their metabolism still emerging.

None of these discoveries would be of much interest outside the lab were it not for some chance observations made in the early 1950s—that, for instance, an antitubercular drug that had induced an unexpected (although not unwelcome) euphoria inhibited an enzyme that breaks down serotonin, or that lysergic acid diethylamide (LSD), already famous for its profound effects on consciousness, has a chemical structure similar to serotonin. Out of these and other
findings, scientists began to cobble together a theory: that mental illness in general and depression in particular are caused by imbalances in neurotransmitters, and especially in serotonin. This theory was of obvious interest to pharmaceutical companies, and by 1958 drugs had come to market designed to cure depression by fixing these supposed imbalances. In 1988, Prozac was introduced, and by 2005, the last year for which reliable figures are available, 27
million Americans
—10 percent of the adult population—were taking antidepressants, most of which act on serotonin, at an annual cost of more than ten billion dollars. It was a success far beyond anything Abbott could have dreamed of when they sent their serotonin to John Welsh’s lab.

This is how the best science stories start—with a chance discovery that leads to a vast change in our everyday lives. Take the brilliant insight, the dogged determination, and the sheer good fortune behind an achievement like Betty Twarog’s, throw in the poignant contrast between her anonymity and the significance of the knowledge she uncovered, add to it some gee-whiz-interesting science, and the next thing you know you have not only a great tale, but also an excellent example of the way that scientists take us up toward Parnassus—in this case the heights of happiness and health. A good science story can make you feel even better about progress and the prospects for humankind.

That’s not the kind of story I’m going to tell in this book.

The invention of antidepressants is not the kind of achievement that contributes unambiguously to the betterment of our species. You probably already suspect that. Unless you’ve been living off the grid for the last half century, and especially the past two decades, you already know that serotonin has become a household word and Prozac and its chemical cousins—known collectively as selective serotonin reuptake inhibitors, or SSRIs—have become staples of the American medicine chest. And you know about the controversies that have ensued. You’ve had conversations about them with
friends or family—or with yourself, when you wondered if your unhappiness or worry were signs of the disease we call depression, or when your doctor wrote a prescription for you and you hesitated to fill it, or when you took the pills, felt better, and wondered what that meant about you. And you’ve probably found that these discussions leave you just as confused as you were before. One thing antidepressants don’t do is end confusion about antidepressants. You’d need a different drug to do that.

You’ll also need a different book to do that. I’m not going to end this confusion for you. In part, that’s because my subject is not the drugs so much as the condition they purport to treat, the disease of depression. But it’s also because ongoing uncertainty is a hazard of reading a book by an old-fashioned psychotherapist like me, who believes that when it comes to important and complex questions, the best approach is to leave yourself in doubt for as long as possible, to live with inner conflict rather than to end it, to withstand yourself rather than to become someone different, to understand how you arrived at an important juncture rather than strike out down a road simply for the sake of getting on with life.

In this case, the crossroads that we’ve all arrived at is as crucial as it gets, and what I will do in this book is to show you how we arrived here, how we got to a point in our history where it is common, if not mandatory, to think of our unhappiness as a disease. And I’m going to do something else here: to try to convince you that what is at stake with antidepressants and the disease they treat isn’t only the question of whether or not to take drugs for our unhappiness, or even whether or not it’s really a good idea to call our unhappiness clinical depression. What’s at stake is who we are, what kind of people we want to be, what we think it means to be human.

If that seems like a stretch, then you should listen to Peter Kramer.

One of the strangest things about the antidepressant revolution, and one indication that more is going on here than biochemistry, is
that the drugs that started it—the SSRIs, which first appeared in the United States in 1988—are
no more effective at treating depression
than the generation of drugs invented in the immediate aftermath of Betty Twarog’s discovery. And that’s not very effective. Nearly half the time,
the drugs fail to outperform placebos
in clinical trials. In real life (which generally lasts longer than a clinical trial and allows for modifications in dosage and brand), they seem to make a positive difference in perhaps 60 percent of the people who take them. You would think that if depression were really biochemical in nature and the drugs were really targeted at the culprit, they’d work better than that. Of course, the first part of that statement remains speculative: despite their best efforts—and notwithstanding what doctors tell their patients when they prescribe them antidepressants—scientists have yet to find a single brain anomaly that is correlated with all cases of depression, let alone one that causes it.

There are many reasons that antidepressants took hold despite these inconvenient truths, but one of the most important factors in their ascent was Kramer’s
Listening to Prozac,
which began to fly off of bookstore shelves in the mid-1990s, about the same time that Prozac prescriptions began to fly off of doctors’ pads. Kramer managed to articulate something that all of us—patients, their families and friends, doctors, and drug companies—needed: a credible justification for taking drugs whose principal effect was to make us feel better about ourselves.
Listening to Prozac
helped make the world safe for antidepressants.

In his book, Kramer starts out like many of us do about this subject—tentative, searching, ambivalent. As he gathers momentum, however, his case for using the drugs—not only to treat depression, but to
“remake the self,”
as his subtitle put it—grows stronger, until it turns into a restrained but unmistakable endorsement. And while you have to wonder about that title—Eli Lilly himself couldn’t have asked for better product placement—the fact that permission came not from an ad man but from a neutral expert, a sensitive and honest
and articulate eyewitness to the revolution, only strengthened the case for the drugs.

Listening to Prozac
ends with a prophecy. Having spent the better part of three hundred pages worrying over the complexities of using drugs to solve our problems, Kramer speculates that questions like these may already be pointless.

By now, asking about the virtue
of Prozac…may seem like asking whether it was a good thing for Freud to have discovered the unconscious. Once we are aware of the unconscious, once we have witnessed the effect of Prozac, it is impossible to imagine the modern world without them. Like psychoanalysis, Prozac exerts influence not only in its interaction with individual patients, but through its effect on contemporary thought. In time, I suspect we will come to discover that modern psychopharmacology has become, like Freud in his day, a whole climate of opinion under which we conduct our different lives.

Antidepressants’ most important side effect, Kramer seems to be saying, is the way they change our understanding of ourselves—altering not only our neurochemistry but our sense of its importance. And once that has happened, there’s no more point in inquiring into their virtues than there is in wondering if winter ought to be so cold and snowy. It’s an ironic end to a book that asks about little besides Prozac’s virtue—and which did so much to usher in the climate of opinion under which we think of our unhappiness as a disease.

Kramer borrowed the phrase
climate of opinion
from
W. H. Auden’s elegy
“In Memory of Sigmund Freud.” Freud, Auden wrote, was no longer just a person:

he quietly surrounds all our habits of growth
and extends, till the tired in even
the remotest miserable duchy
have felt the change in their bones and are cheered

There was a time, and it wasn’t very long ago, when people didn’t feel in their bones that they “had depression,” when the Centers for Disease Control weren’t calling depression “
the common cold of mental illness
,” when the World Health Organization wasn’t claiming that depression was “
the leading cause of disability
…and the 4th leading contributor to the global burden of disease.” It is possible that doctors have gotten better at recognizing depression. It’s possible that contemporary life imposes demands that exceed the neurochemistry bequeathed to us by natural selection. It’s even possible that global warming, widespread warfare, the worldwide economic collapse—that these seemingly irremediable conditions are making us sick with worry. Indeed, all of these explanations for the apparent depression epidemic could be true at the same time, but there is another possible explanation: every new climate of opinion about who we are has its distinctive form of lousy weather. Clinical depression—unhappiness rendered as disease—is ours.