However, the changes took longer to appear in those patients who responded to the dummy pill.
Nine thousand patients were given either Vytorin or a dummy pill for an average of five years.
In Hankins' study, about 260 U.S. women with morning sickness were given either Diclegis or a dummy pill for two weeks.
He agreed that a further trial in a larger number of patients, comparing vitamin D with a dummy pill was warranted.
But while it is easy to compare the efficacy of, say, Viagra, with that of a dummy pill, it is harder to come up with a placebo to prove the worth of such things as minor surgery.
Of the adverse events reported in this blinded study (where the patient, investigator and company do not know whether the patient received Seroxat or a dummy pill) only one - headache - was attributed by the independent investors to Seroxat.
Patients who stuck to the regimen cleared the infection in 23 days on average, while it took patients 36 days if they were given antibiotics and a dummy sugar pill.
The researchers found that the drugs did have a positive impact on people with mild depression - but the effect was no bigger than that achieved by giving patients a sugar-coated "dummy" pill.
The US Food and Drug Administration (FDA) approved Levitra, an orange pill compared to Viagra's blue, based on studies showing that men were on average five times more likely to achieve an erection suitable for intercourse when taking the pill compared with those given a dummy medicine.
应用推荐