Around one-sixth of all adults, and proportionately many more among the elderly, have an overactive bladder. Symptoms include a sudden urgency to urinate, urinary incontinence, frequent urination, and nocturia, which is a need to urinate during the night.
If you decide to see your doctor about it, he will prescribe an anticholinergic drug. We know they cause side-effects such as dry mouth and eyes, constipation, headache and nausea - but we don't know if they work.
Researchers at Otago University in New Zealand researched 32 studies that were double-blind - the participants were given either the drug or a placebo, but they did not know which they were being given.
To the researchers' surprise, the anticholinergic drug worked well - and so did the placebo. In fact, there was virtually no difference in their effectiveness except that the placebo didn't come with the side-effects.
The researchers concluded that the effectiveness of drug therapy was debatable - but they missed the real point. If people think they're getting a drug, their overactive bladder problems all but disappear - all of which throws open the whole question of the role of the mind in dealing with health problems.
(Source: British Medical Journal, 2003; 326: 841-4).