Depression has increased at an alarming rate since the introduction of antidepressant drugs. The following extract from a published article used to be on my website for Adaptation Practice: stop stress, anxiety, anger and depression, but Adaptation Practice is a safe and effective way of stopping depression and the website is not a platform to criticise conventional treatments.
Quoted from The New York Review of Books: (You can read the whole article here.)
The Epidemic of Mental Illness: Why?
by Irving Kirsch
Basic Books, 226 pp., $15.99 (paper)
by Robert Whitaker
Crown, 404 pp., $26.00
by Daniel Carlat
Free Press, 256 pp., $25.00
‘What is going on here? Is the prevalence of mental illness really that high and still climbing? Particularly if these disorders are biologically determined and not a result of environmental influences, is it plausible to suppose that such an increase is real? Or are we learning to recognize and diagnose mental disorders that were always there? On the other hand, are we simply expanding the criteria for mental illness so that nearly everyone has one? And what about the drugs that are now the mainstay of treatment? Do they work? If they do, shouldn’t we expect the prevalence of mental illness to be declining, not rising?
These are the questions, among others, that concern the authors of the three provocative books under review here. They come at the questions from different backgrounds—Irving Kirsch is a psychologist at the University of Hull in the UK, Robert Whitaker a journalist and previously the author of a history of the treatment of mental illness called Mad in America (2001), and Daniel Carlat a psychiatrist who practices in a Boston suburb and publishes a newsletter and blog about his profession.
The authors emphasize different aspects of the epidemic of mental illness. Kirsch is concerned with whether antidepressants work. Whitaker, who has written an angrier book, takes on the entire spectrum of mental illness and asks whether psychoactive drugs create worse problems than they solve. Carlat, who writes more in sorrow than in anger, looks mainly at how his profession has allied itself with, and is manipulated by, the pharmaceutical industry. But despite their differences, all three are in remarkable agreement on some important matters, and they have documented their well.
First, they agree on the disturbing extent to which the companies that sell psychoactive drugs—through various forms of marketing, both legal and illegal, and what many people would describe as bribery—have come to determine what constitutes a mental illness and how the disorders should be diagnosed and treated. This is a subject to which I’ll return.
Second, none of the three authors subscribes to the popular theory that mental illness is caused by a chemical imbalance in the brain. As Whitaker tells the story, that theory had its genesis shortly after psychoactive drugs were introduced in the 1950s. The first was Thorazine (chlorpromazine), which was launched in 1954 as a “major tranquilizer” and quickly found widespread use in mental hospitals to calm psychotic patients, mainly those with schizophrenia. Thorazine was followed the next year by Miltown (meprobamate), sold as a “minor tranquilizer” to treat anxiety in outpatients. And in 1957, Marsilid (iproniazid) came on the market as a “psychic energizer” to treat depression.
In the space of three short years, then, drugs had become available to treat what at that time were regarded as the three major categories of mental illness—psychosis, anxiety, and depression—and the face of psychiatry was totally transformed. These drugs, however, had not initially been developed to treat mental illness. They had been derived from drugs meant to treat infections, and were found only serendipitously to alter the mental state. At first, no one had any idea how they worked. They simply blunted disturbing mental symptoms. But over the next decade, researchers found that these drugs, and the newer psychoactive drugs that quickly followed, affected the levels of certain chemicals in the brain.
Some brief—and necessarily quite simplified—background: the brain contains billions of nerve cells, called neurons, arrayed in immensely complicated networks and communicating with one another constantly. The typical neuron has multiple filamentous extensions, one called an axon and the others called dendrites, through which it sends and receives signals from other neurons. For one neuron to communicate with another, however, the signal must be transmitted across the tiny space separating them, called a synapse. To accomplish that, the axon of the sending neuron releases a chemical, called a neurotransmitter, into the synapse. The neurotransmitter crosses the synapse and attaches to receptors on the second neuron, often a dendrite, thereby activating or inhibiting the receiving cell. Axons have multiple terminals, so each neuron has multiple synapses. Afterward, the neurotransmitter is either reabsorbed by the first neuron or metabolized by enzymes so that the status quo ante is restored. There are exceptions and variations to this story, but that is the usual way neurons communicate with one another.
When it was found that psychoactive drugs affect neurotransmitter levels in the brain, as evidenced mainly by the levels of their breakdown products in the spinal fluid, the theory arose that the cause of mental illness is an abnormality in the brain’s concentration of these chemicals that is specifically countered by the appropriate drug. For example, because Thorazine was found to lower dopamine levels in the brain, it was postulated that psychoses like schizophrenia are caused by too much dopamine. Or later, because certain antidepressants increase levels of the neurotransmitter serotonin in the brain, it was postulated that depression is caused by too little serotonin. (These antidepressants, like Prozac or Celexa, are called selective serotonin reuptake inhibitors (SSRIs) because they prevent the reabsorption of serotonin by the neurons that release it, so that more remains in the synapses to activate other neurons.) Thus, instead of developing a drug to treat an abnormality, an abnormality was postulated to fit a drug.
That was a great leap in logic, as all three authors point out. It was entirely possible that drugs that affected neurotransmitter levels could relieve symptoms even if neurotransmitters had nothing to do with the illness in the first place (and even possible that they relieved symptoms through some other mode of action entirely). As Carlat puts it, “By this same logic one could argue that the cause of all pain conditions is a deficiency of opiates, since narcotic pain medications activate opiate receptors in the brain.” Or similarly, one could argue that fevers are caused by too little aspirin.
But the main problem with the theory is that after decades of trying to prove it, researchers have still come up empty-handed. All three authors document the failure of scientists to find good evidence in its favor. Neurotransmitter function seems to be normal in people with mental illness before treatment. In Whitaker’s words:
Prior to treatment, patients diagnosed with schizophrenia, depression, and other psychiatric disorders do not suffer from any known “chemical imbalance.” However, once a person is put on a psychiatric medication, which, in one manner or another, throws a wrench into the usual mechanics of a neuronal pathway, his or her brain begins to function…abnormally.
Carlat refers to the chemical imbalance theory as a “myth” (which he calls “convenient” because it destigmatizes mental illness), and Kirsch, whose book focuses on depression, sums up this way: “It now seems beyond question that the traditional account of depression as a chemical imbalance in the brain is simply wrong.” Why the theory persists despite the lack of evidence is a subject I’ll come to.
Do the drugs work? After all, regardless of the theory, that is the practical question. In his spare, remarkably engrossing book, The Emperor’s New Drugs, Kirsch describes his fifteen-year scientific quest to answer that question about antidepressants. When he began his work in 1995, his main interest was in the effects of placebos. To study them, he and a colleague reviewed thirty-eight published clinical trials that compared various treatments for depression with placebos, or compared psychotherapy with no treatment. Most such trials last for six to eight weeks, and during that time, patients tend to improve somewhat even without any treatment. But Kirsch found that placebos were three times as effective as no treatment. That didn’t particularly surprise him. What did surprise him was the fact that antidepressants were only marginally better than placebos. As judged by scales used to measure depression, placebos were 75 percent as effective as antidepressants. Kirsch then decided to repeat his study by examining a more complete and standardized data set.
The data he used were obtained from the US Food and Drug Administration (FDA) instead of the published literature. When drug companies seek approval from the FDA to market a new drug, they must submit to the agency all clinical trials they have sponsored. The trials are usually double-blind and placebo-controlled, that is, the participating patients are randomly assigned to either drug or placebo, and neither they nor their doctors know which they have been assigned. The patients are told only that they will receive an active drug or a placebo, and they are also told of any side effects they might experience. If two trials show that the drug is more effective than a placebo, the drug is generally approved. But companies may sponsor as many trials as they like, most of which could be negative—that is, fail to show effectiveness. All they need is two positive ones. (The results of trials of the same drug can differ for many reasons, including the way the trial is designed and conducted, its size, and the types of patients studied.)
For obvious reasons, drug companies make very sure that their positive studies are published in medical journals and doctors know about them, while the negative ones often languish unseen within the FDA, which regards them as proprietary and therefore confidential. This practice greatly biases the medical literature, medical education, and treatment decisions.
Kirsch and his colleagues used the Freedom of Information Act to obtain FDA reviews of all placebo-controlled clinical trials, whether positive or negative, submitted for the initial approval of the six most widely used antidepressant drugs approved between 1987 and 1999—Prozac, Paxil, Zoloft, Celexa, Serzone, and Effexor. This was a better data set than the one used in his previous study, not only because it included negative studies but because the FDA sets uniform quality standards for the trials it reviews and not all of the published research in Kirsch’s earlier study had been submitted to the FDA as part of a drug approval application.
Altogether, there were forty-two trials of the six drugs. Most of them were negative. Overall, placebos were 82 percent as effective as the drugs, as measured by the Hamilton Depression Scale (HAM-D), a widely used score of symptoms of depression. The average difference between drug and placebo was only 1.8 points on the HAM-D, a difference that, while statistically significant, was clinically meaningless. The results were much the same for all six drugs: they were all equally unimpressive. Yet because the positive studies were extensively publicized, while the negative ones were hidden, the public and the medical profession came to believe that these drugs were highly effective antidepressants.
Kirsch was also struck by another unexpected finding. In his earlier study and in work by others, he observed that even treatments that were not considered to be antidepressants—such as synthetic thyroid hormone, opiates, sedatives, stimulants, and some herbal remedies—were as effective as antidepressants in alleviating the symptoms of depression. Kirsch writes, “When administered as antidepressants, drugs that increase, decrease or have no effect on serotonin all relieve depression to about the same degree.” What all these “effective” drugs had in common was that they produced side effects, which participating patients had been told they might experience.
It is important that clinical trials, particularly those dealing with subjective conditions like depression, remain double-blind, with neither patients nor doctors knowing whether or not they are getting a placebo. That prevents both patients and doctors from imagining improvements that are not there, something that is more likely if they believe the agent being administered is an active drug instead of a placebo. Faced with his findings that nearly any pill with side effects was slightly more effective in treating depression than an inert placebo, Kirsch speculated that the presence of side effects in individuals receiving drugs enabled them to guess correctly that they were getting active treatment—and this was borne out by interviews with patients and doctors—which made them more likely to report improvement. He suggests that the reason antidepressants appear to work better in relieving severe depression than in less severe cases is that patients with severe symptoms are likely to be on higher doses and therefore experience more side effects.
To further investigate whether side effects bias responses, Kirsch looked at some trials that employed “active” placebos instead of inert ones. An active placebo is one that itself produces side effects, such as atropine—a drug that selectively blocks the action of certain types of nerve fibers. Although not an antidepressant, atropine causes, among other things, a noticeably dry mouth. In trials using atropine as the placebo, there was no difference between the antidepressant and the active placebo. Everyone had side effects of one type or another, and everyone reported the same level of improvement. Kirsch reported a number of other odd findings in clinical trials of antidepressants, including the fact that there is no dose-response curve—that is, high doses worked no better than low ones—which is extremely unlikely for truly effective drugs. “Putting all this together,” writes Kirsch,
leads to the conclusion that the relatively small difference between drugs and placebos might not be a real drug effect at all. Instead, it might be an enhanced placebo effect, produced by the fact that some patients have broken [the] blind and have come to realize whether they were given drug or placebo. If this is the case, then there is no real antidepressant drug effect at all. Rather than comparing placebo to drug, we have been comparing “regular” placebos to “extra-strength” placebos.
That is a startling conclusion that flies in the face of widely accepted medical opinion, but Kirsch reaches it in a careful, logical way. Psychiatrists who use antidepressants—and that’s most of them—and patients who take them might insist that they know from clinical experience that the drugs work. But anecdotes are known to be a treacherous way to evaluate medical treatments, since they are so subject to bias; they can suggest hypotheses to be studied, but they cannot prove them. That is why the development of the double-blind, randomized, placebo-controlled clinical trial in the middle of the past century was such an important advance in medical science. Anecdotes about leeches or laetrile or megadoses of vitamin C, or any number of other popular treatments, could not stand up to the scrutiny of well-designed trials. Kirsch is a faithful proponent of the scientific method, and his voice therefore brings a welcome objectivity to a subject often swayed by anecdotes, emotions, or, as we will see, self-interest.’