Briefs

--P

The placebo effect--the expectation that about 35% of patients will show improvement if they are given any kind of treatment at all, even a sugar pill--is one of the givens of modern medicine and, for true believers, the best evidence of the healing power of mind over body. But is it real? Two Danish researchers set out to test it by reviewing 114 clinical trials in which patients were given a real medicine, a placebo or no treatment at all. Their analysis, published last week in the New England Journal of Medicine, showed that placebos offer no significant advantage over "no treatment" for dozens of conditions ranging from colds and seasickness to hypertension and Alzheimer's disease. (The exception is pain relief, which sugar pills seem to bring to about 15% of patients.) Dr. Asbjorn Hrobjartsson of the University of Copenhagen, who led the study, speculates that much of the improvement attributed to the placebo effect may have been the result of a disease's natural fluctuation or of patients' unconscious desire to please their doctors.

--Tea Party

Sip away tooth decay? Well, maybe, if the drink is tea, scientists reported at last week's meeting of the American Society for Microbiology. In a preliminary study--financed by the tea industry--volunteers swished either black tea or lukewarm water in their mouth. An analysis of their saliva showed that tea inhibits the growth of tooth-decaying bacteria and reduces their tendency to form sticky clumps. In addition, tea drinkers' saliva contains less enamel-eroding acid. Does that translate into fewer cavities? Probably. In previous clinical trials, green tea was shown to prevent cavities, and these new findings lead researchers to suspect that black tea will too--as long as it's not sweetened with sugar or honey.

--Botox for the Back

Botulinum toxin--yes, the same poison that causes muscle paralysis when ingested in bad restaurants and smooths forehead wrinkles in trendy clinics--may also relieve aching backs. Scientists report in the journal Neurology that patients with longstanding lower-back pain who receive Botox injections are three times as likely as those who get injected with a saline solution to report less pain and less difficulty walking, sitting and exercising. The shots, five in all, not only eased muscle spasms along the spine--which might be expected, given Botox's known muscle-relaxing effects--but somehow also quieted the nerve firings that cause pain. Unfortunately, the effects wear off after about three months.

--The Diabetes Blues

Everybody knows that diabetes is no fun. But researchers writing in this month's Diabetes Care report that diabetics are twice as likely to suffer from depression as the rest of us. Depression, it turns out, often precedes the onset of diabetes--and may contribute to it. Depressed patients often overeat and have sedentary lifestyles, both of which may promote insulin resistance. Furthermore, some antidepressants, particularly the older tricyclics, disrupt glucose control. The good news: proper treatment of depression may actually improve diabetes.