Risk in a ‘Pill Society’

In July, researchers at the Mayo Clinic in Rochester, Minn., found that a combination of drugs commonly used to combat obesity were associated with dangerous heart problems. The implications were clear enough: The drug combination known as fen-phen should be prescribed only when the health risks of obesity markedly exceed the risks of the drugs.

Last week, however, researchers at the National Institute of Mental Health (NIMH) discovered another problem associated with one of the diet drugs, fenfluramine. The discovery has broad implications. That’s because the drug works in ways similar to Prozac and many of the other highly popular, relatively new antidepressant drugs called “selective serotonin re-uptake inhibitors,” or SSRIs. By preventing the “re-uptake” or absorption of a chemical called serotonin, these drugs enhance pleasant emotions (like happiness) while diminishing unpleasant ones. The new study found that fenfluramine not only prevents the absorption of serotonin but also diminishes the brain’s sensitivity to serotonin.

The researchers did not explore whether the same is true of SSRIs like Prozac, and after more than a decade of use there is no specific evidence that they harm the brain in any way. Nevertheless, given that Americans are now taking hundreds of new drugs that scientists are only beginning to understand, the NIMH study should remind us not to assume that medicine is all-knowing.

Consider the recent confession by Harvard Medical School psychiatrist William S. Appleton that he has barely begun to understand serotonin’s effect on the synapse, the space between brain cells where it is absorbed. “I have begun to regard the serotonin synapse,” Appleton writes, “the same way I think of my radio when it does not work--I hit it and it often starts broadcasting again. I have begun to believe that is what these antidepressants do to the synapse--they hit it.”

That may be a good hunch. But it’s still a far cry from a scientific understanding of drugs we have come to take almost as unthinkingly as aspirin.