Waiting for the Next Magic Pill
By Talia Puzantian
In the more than quarter century since the arrival of Prozac, the drug that Newsweek’s cover once declared the “breakthrough drug for depression,” we’ve seen the landscape of the mental health field transformed by the extraordinary growth of the psychopharmacology industry. Combined sales of antidepressants and antipsychotics in the United States accounted for less than $500 million in 1987, but annual sales today exceed $29 billion. Currently, 1 in 8 people regularly takes psychotropic medications, 10 percent of the entire population over the age of 6 use some kind of antidepressant, and antipsychotics have replaced cholesterol-lowering agents as the top-selling prescription drugs. While the number of people in psychotherapy has declined over the past decade, the multibillion-dollar advertising offensive waged by the drug companies year after year has succeeded in convincing the media and the general population that many psychological problems are primarily the result of chemical imbalances within the brain.
Amid the many controversies surrounding the influence of the drug companies on the quality of mental health care, one important fact about the medications brought to market over the past 25 years has received little attention—few represented any real advance in the science of psychopharmacology or any real expansion of our understanding of how to regulate the nervous system with chemicals. Almost all of the so-called “new” drugs have targeted the same mechanisms of action as those already in use, with only slight modifications in potency, receptor selectivity, metabolism, rate of absorption, or other pharmacokinetic properties. Most of the new psychotropic medications approved in recent years have been me-too drugs, chemical cousins of medications already on the market, introduced to compete against another company’s medication within an existing chemical class of drugs, or to replace a company’s own drug that was about to lose its patent protection to generic equivalents. Yet almost none of these meds has proven to offer distinct advantages over existing, usually less expensive, agents.
Here, as in other aspects of the development of pharmacological approaches to mental health treatment, it’s important to acknowledge the role that business considerations, rather than scientific discovery or genuine improvements in treatment outcomes, play in determining what new medications come on the market and become available to clinicians. For the pharmaceutical industry, developing a me-too drug is less time-consuming and more profitable than developing a completely novel chemical entity aimed at a new target mechanism of action. When a drug designed to treat any given condition is profitable, the company that sells it has no incentive to put forth a competitor. However, when a drug is close to losing patent protection, the company has a great incentive to move patients taking it over to a newer agent, rather than lose them to the cheaper generic equivalent. For example, just before Celexa was to become available as a generic, its manufacturer launched Lexapro, which contains only the more pharmacologically active half of Celexa.
The economic reality for the pharmaceutical company is that once a drug loses its patent protection, generic versions of it begin to be sold by other companies for a tiny fraction of the cost of the branded product. When that happens, companies stop advertising that medication, new indications are no longer sought out, and—given that the overwhelming majority of drug trials are industry funded—no more clinical trials are conducted. The drug, in effect, is put out to pasture.
Sometimes, however, an old drug proves to have therapeutic potency for a condition other than the one it was originally designed to target. A striking example is the discovery that a blood-pressure medication called prazosin can reduce the nightmares, hyperarousal, and avoidance symptoms frequently associated with post-traumatic stress disorder (PTSD). But most people haven’t heard about this new clinically valuable use of the drug—and for a good reason. Prazosin is inexpensive and already available generically, so a multimillion-dollar advertising campaign won’t be launching on its behalf anytime soon.
After the seeming boom times of the past couple of decades, nearly every major company in the psychopharmacology industry has either significantly decreased or abandoned its psychiatric drug-discovery efforts. The industry has concluded that this area of research is economically too risky. From 1975 to 2005, the average cost to develop a new drug increased from $100 million to $1.3 billion (in adjusted dollars), with the cost for psychiatric drugs even higher. At the same time, the risk for failure continues to be steep. Nearly 80 percent of drugs fail to advance beyond Phase III, the last and most expensive preapproval phase of clinical human trials, because of lack of efficacy or safety concerns. Accordingly, the drug companies have chosen to allocate their resources in areas like cancer treatment and immunology, which they consider better business investments with fewer downsides.