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After thousands of studies, hundreds of millions of prescriptions and billions of dollars in sales, two things are certain about pills that treat depression: Anti-depressants like Prozac, Paxil and Zoloft work. And so do sugar pills.
A new analysis has found that in the majority of trials conducted by drug companies in recent decades, sugar pills have done as well as - or better than - anti-depressants. What’s more, the sugar pills, or placebos, cause profound changes in the same areas of the brain affected by the medicines.
One researcher has ruefully concluded that a higher percentage of depressed patients get better on placebos today than 20 years ago. Placebos - or dud pills - have long been used to help scientists separate the “real” effectiveness of medicines from the “illusory” feelings of patients. The placebo effect - the phenomenon of patients feeling better after they’ve been treated with dud pills - is seen throughout the field of medicine.
But new research suggests that the placebo may play an extraordinary role in the treatment of depression - where how people feel spells the difference between sickness and health.
The new research may shed light on findings such as those from a trial last month that compared the herbal remedy St. John’s wort against Zoloft. St. John’s wort fully cured 24 percent of the depressed people who received it, and Zoloft cured 25 percent - but the placebo fully cured 32 percent. The findings do not mean that anti-depressants do not work. But clinicians and researchers say the results do suggest that Americans may be overestimating the power of the drugs and that the medicines’ greatest benefits may come from the care and concern shown to patients during a clinical trial - a context that does not exist for millions of patients using the drugs in the real world.
“The drugs work, and I prescribe them, but they are not what they are cracked up to be,” said Wayne Blackmon, a Washington psychiatrist. “I know from clinical experience the drugs alone don’t do the job.” Still, drugs may have become the reflexive treatment for the vast majority of Americans receiving medical attention for depression: As the number of doctor visits for depression rose from 14 million in 1987 to almost 25 million last year, medications were prescribed for nine in 10 patients Seattle psychiatrist Arif Khan studied the placebo effect in trials submitted to the Food and Drug Administration. His analysis of 96 anti-depressant trials between 1979 and 1996 showed that in 52 percent of them, the effect of the anti-depressant could not be distinguished from that of the placebo.
Khan said the makers of Prozac had to run five trials to obtain two that were positive, and the makers of Paxil and Zoloft had to run even more. “It speaks to the difficulty we have in classifying and identifying the disorders we deal with,” said Thomas Laughren, who heads the group of scientists at the FDA that evaluates the medicines.
Scientists don’t understand the neural mechanisms of depression - or why medicines like Prozac and Paxil work.
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