Placebo Power Fights Depression

Placebo power can be embarrassing. A recent study of St. John’s wort found that it was no more effective against major depression than placebo-but neither was Zoloft, the prescription antidepressant to which it was compared.
While the headlines blazed, “Herbal Remedy Doesn’t Work,” hardly any noted that a prescription antidepressant taken by millions of people was equally unsuccessful.
Why do researchers use inactive placebos in scientific studies? There is a general recognition that if you give patients a pill-any pill, even one that is filled with nothing but sugar-they often get better.
To prove that a new drug really works, the FDA requires two clinical trials demonstrating superiority over placebo. That way, there is some assurance that the improvement wasn’t due to either the natural course of the illness or sympathetic attention. In a double-blind trial, patients taking placebo pills get just as much attention, and nobody knows who is taking what until the study is over.
Placebos can work for almost any condition. But they seem to work especially well for people suffering from depression. Perhaps that is why the makers of medicines like Prozac had to run so many trials to meet the FDA’s requirement for approval.
Drug companies don’t often publish studies that aren’t favorable. When a drug like Zoloft or Paxil doesn’t perform better than a placebo there isn’t a lot of motivation to make that information public.
One way to find out what’s really going on is to search the FDA’s records. A recent review looked at almost 100 antidepressant clinical trials performed between 1979 and 1996. It found that in more than half of these studies (many of them unpublished) the medications were not significantly better than placebo.
There are two explanations for this anomaly. One is that medications like Prozac, Paxil or Zoloft are not as effective against depression as doctors and patients like to think. Another possibility is that placebos actually work a lot better than most people imagine.
Whatever the explanation, this poses a dilemma for physicians. Should they be prescribing antidepressants like Effexor, Serzone, Celexa, Paxil, Prozac and Zoloft as widely as they do? For one thing, these are expensive drugs. A month’s supply can cost $60 or more. For another, they can cause side effects. Some people experience anxiety, agitation, insomnia, nausea, headache or sexual dysfunction.
Perhaps physicians should try to harness placebo power. Placebos are cheap, and though they can cause side effects, the complications are not due to biological activity. It is not uncommon, however, for 30 to 50 percent of depressed patients receiving inactive placebo pills to report significant improvement.
Physicians should listen sympathetically to patients with mild to moderate depression. They might also encourage patients to seek supportive psychotherapy and reinforce the value of outdoor light exposure and exercise.
For those who would like to know more about antidepressants, we offer a free copy of our Guide to Antidepressant Pros & Cons (please send a long (no. 10) stamped, self-addressed envelope: Graedons’ People’s Pharmacy, No. X-Free, P. O. Box 52027, Durham, NC 27717-2027.